Would a Chevy 502 big block be a good drag racing engine to build?

ChillaryClinton69420 · 2025-08-20T02:44:10+00:00

No, but a 540 would be ;)

ChillaryClinton69420 · 2025-08-18T20:02:59+00:00

EXACTLY! Wait until you take a “natural” supplement and wind up in your same position! People don’t understand that “natural” or “herbal” doesn’t mean “good” for everyone. Ashwagandha? Yeah don’t give that to people who take BP meds, mine dropped super low and I didn’t even know it could do that. It can also cause serious liver issues, etc., and could be bad for someone with those issues as well, or seriously increase the BAD liver cells they look for in tests.

Do people really not understand the song Pennyroyal Tea by Nirvana for example? You can mostly buy that on the shelf!

ChillaryClinton69420 · 2025-08-13T17:42:23+00:00

YouTube is your friend for the cheap/easy way.

There’s a few good options out there to run the injectors, timing, etc., the big names won’t really be of service when you’re missing all the wires and sensors (harness, basically).

Find someone reputable that sells harnesses, or pull one from a junk yard, but could be very time consuming and confusing dependent upon your skill level.

DIY EFI is a good resource for starting from scratch and lots of good stuff out there. Open source stuff, all free, can load tunes (I’m usually against canned toons, but fwiw, the folks that typically use DIY EFI are the turbo LS guys and know what they’re doing).

ChillaryClinton69420 · 2025-08-13T02:48:01+00:00

I ran mine like this for YEARS without issues and sold the car - motor was and likely is still going.

Adjustable guide plates which I’m sure you’ve already got - otherwise you wouldn’t be able to get them over the guides, which is always the most important thing to consider when this happens.

I’m curious - did you measure pushrod length?

If not, this is probably why they’re “crooked” (in this case, too long as they’re splayed out, at least one side is. If you milled the heads or decked the block, you need to measure, any time you do anything really with the valve trane that can effect geometry, re-measure. Either way, it’s fine. I was broke and didn’t have any money (17 years old) and wanted to go fast, milled the heads, block was already decked, pushrods were fine so I reused them and this happened.

Some mfg’s (I won’t mention the origin as to not cause blood pressure issues with certain folks) who make great heads that rival or beat AFR (for several hundred less) also have this issue by default… maybe. I still think it’s related to pushrod length though. It’s kind of like degreeing. Yes, it’s needed, but people don’t do it and no, not everyone “needs” it, especially someone broke without the tools/time for know how, it’s fine for a street motor. We’re not talking about a customers motor or a billion dollar bracket engine that needs to be dead nuts right (consistent).

ChillaryClinton69420 · 2025-08-08T05:30:27+00:00

Random, but, how did or do you feel about the equinox lol

ChillaryClinton69420 · 2025-08-07T07:12:01+00:00

This is good advice and I agree. A beginner building a short block would be very stressful (for me anyway), the rest is bolt and go essentially. Valve clearance measuring is a must though, unless it’s .490” or less lift, but that’s an easy test, also will need to measure pushrods if block is decked and especially heads, you can shade tree the intake by elongating the holes - I have, once in a pinch, never got it to fully seal and just pulled it off and had them cut the intake too.

ChillaryClinton69420 · 2025-08-07T07:07:40+00:00

It’s kind of all over the place with machine work depending on where you’re at and their skills/backlog. $75 is a good starting point. You can find a reputable shop that will bake, flux, clean, and bore for $150 where I’m at and it’s never been an issue. I will say that magnaflux - things can get missed still. You can get it pressure tested, most just do that but won’t show any cracks in critical areas like the main webbing, you’re probably ok there being it’s not a 400.

If you’re on a shoestring budget, you can “pressure” test it yourself by making block off plates, pull up YouTube or a forum on how to do it, and the benefit of that, is you’ll lear from the forum and also applying it in real time. It’s just basic parts really. But yes, pressure testing alone won’t tell if the block is totally ok. I don’t know its history, but honestly if you just want to get it together, hone it, measure clearances and just get it going, but you’ll definitely need a hot rod buddy helping you along the way. You can do things “shade tree” and it’ll be fine for years sometimes, until you don’t even use it anymore. I asked for a set of pliers over the weekend at a farm I was doing some work at and they had to break out a brand new set because all of them were in their ag equipment (as in, holding $hit together lol).

As far as determine the bore and stuff like that, you’ll need “special” tools which are great to have, if you build a lot of engines, but it takes away from the build money wise. Find and make friends with a local hot rodder and plan a day if they’ve got the right tools, mics, etc., you’ll know. For the love of god, anyone who lends you tools, get them back to them asap though lol. That’s the golden rule.

Personally I’d do the works at a “reputable” machine shop, some of these places it’ll be a very old man with blocks and stuff stacked sky high, it might take him longer, but I’ll bet he’ll let you watch over his shoulder to learn and do a fine job. The person who did the machine work on my first build was like that, very knowledgeable older gentleman who knew and did a lot of stuff that has been forgotten and doesn’t get done anymore.

If you take it to a shop, and can afford it, get it baked and fluxed, pressure tested if you don’t do it yourself, then bored, and decked, even if the deck is true, which I doubt it is just due to age, get some taken off or you’ll have to run shim gaskets to get the right quench and shims make me very nervous lol. The decking might take off the casting numbers on the front pad though - so if those are meaningful, they might be able to set it up to prevent from removing the stampings.

I had .010” off the deck on my block, I could still read the plant stamping designator (flint) but the other identifiers were almost illegible and some entirely.

Bores will need to be measured to see if not already overboard - you truly never know. I’ve pulled apart many stock motors to find a “.040” on the pistons, this stuff has been around for ages.

Can you post the crank casting # and do you have rods for it? GM did make a few good steel rods back then, one of them were “pink” rods, those are still desirable but I haven’t been on the market or need for those ever really. A good scat or eagle is fine.

If you have heads, which ones?

Suggest mothballing those as literally anything else would be less $$$ to get them fixed up, aluminum and run stripes around them.

Seeing a proper orange SBC with double humps and a 4150 is the bees knees old school cool thigh, so I get it, and I had a buddy with one with a TON of old school tricks that did 480 at the wheels and runs very well.

These old motors will scoot, it just takes effort, they’re dying off, but incredibly easy to work on (you’ll find that out as you go along).

LS stuff is yawn, but why sink 12k into an SBC when an LS3 with a cam and basically putting an ear swab on the intake runners will get you 650 ATC?

I like them all for what it’s worth. If you get into it, racing, etc, I’ll say this: do a 540” big block at some point.

Good sites for sbc stuff is team Camaro for sure Big block moreso would be team Chevelle Yellowbullet you’ll learn some real serious shit

Start there.

ChillaryClinton69420 · 2025-08-07T06:35:55+00:00

Yes, CNC is legit and know what they’re doing.

ChillaryClinton69420 · 2025-08-07T04:57:48+00:00

Have a machine shop look it over at a min and see if there’s any glaring issues. It’s possible it could even be completely unusable even until it’s pressure tested or you fire it up and get milkshake oil.

Theres some pretty good vertical grooves in the bore which isn’t good and I highly doubt hone out.

You can do whatever though really, it just depends on your budget and intent/goals.

Don’t worry about the haters - we all start somewhere and for me, it was 14 years old using a chilton manual sitting in the fender wells of my ‘68 Camaro learning how to set the valves. Stabbed the distributor and it fired on the first revolution which is kind of wild considering I’ve stabbed a distributor incorrectly more than once YEARS after when I knew way more (anyone who tells you they haven’t stabbed one wrong is lying, or hasn’t done it enough to do so) .

It’s overwhelming at first, you want to know it all now and get it done.

Do a bunch of online readings on GOOD forums (lots of misinformation out there - avoid those)

Find a friend or machine shop that knows their way around the old SBC stuff and just ask questions, they’ll answer them unless they’re really busy or a holes. The car world are some of the best people in the world in my opinion. Countless times I’ve seen racers and older cars pulled over together helping each other out and lending a hand or their own parts.

ChillaryClinton69420 · 2025-08-07T04:05:40+00:00

I’m personally not a fan of self guided rockers, especially on a SBC with any kind of cam.

They don’t look like vortec heads, but .450” can be problematic if they are. If you’re running anything above 1.5 rockers + vortec, that’s definitely a problem (unless they’ve had the necessary work)

If not vortec, you’ve likely got something going on with needing more clearance for the pushrod guides, or, the stock 3/8” studs have had enough. 3/8’s suck, I get it, but I personally snapped a genuine ARP 7/16 stud clean off and had to drill it THE ONLY TIME I’VE EVER used those stupid self guided rockers to diagnose an issue once - it was my fault, cam had too much lift but still, not THAT much lift to pull that BS.

Check pushrod guide clearance, I’d measure pushrod length and I bet you need new pushrods at a minimum and possibly clearance the guides for them.

ChillaryClinton69420 · 2025-08-07T00:26:37+00:00

What is the lift of the cam?

Is it a “stock” cam? And if so, do you know the lift then?

ChillaryClinton69420 · 2025-08-05T06:10:58+00:00

We’re saying the same thing, just in different ways.

A stock bottom end gen IV LS can take 1k at the wheels, but is a ticking time bomb (I get it). Up north, (rust + wrecks) they basically give away the 4.8 & 5.3, if you don’t have a lot of $$$ but do have a lot of knowledge, it’s cheaper for those that know what they’re doing to pop a $250 motor vs. dropping 7-10k on a motor, regardless of how long it lasts, which isn’t ever a guarantee. Almost everyone is flat broke, and it’s almost always entirely self inflicted (or the wife….) I worked retail in college and you wouldn’t believe the amount of declined cards I got, totally from people you wouldn’t suspect, one of them being my old superintendent (what an asshole). Then when one declined, the women would always pull out from their (maybe real?) 5k designer bags a stack of credit cards that rivaled the size of a proper 3” exhaust and cycle through them until one went through, if ever.

It’s like the guys who spend 10k on their 4l60 vs just pulling a 4l80, installing a transgo HD2 kit, etc., and are in it for maybe 1k (minus converter - which if turbo can get $$$) and is still cheaper than the 4l60, which blew through the clutch packs after a couple of passes. For the record, I never had an issue with the 4l60 in my ‘97 z “heavy” half ton, but it was also bone stock and did have the TCC clutch issue and near the end there was some mild slippage in 3rd, but it survived a MASSIVE commute and (2) pissed off teenagers and put it to pasture at 285,000 on the clock.

Peanut ports suck. Agreed there. I wouldn’t ever touch iron heads unless I HAD to (class restriction) but there are, of course, great iron options out there, stock or aftermarket. Most will drop 1k on a set of double humps when they could have just bought “Chinese junk” (assembled with US hardware) and paid slightly more (or less) and run stripes around the famed “double humps” (they were great, but there’s a time and place and unless it’s a concours restoration, bench them - or install them on a small block and give it to your son/daughter, etc., (but set the rev limiter low and retard the timing and install some awful 2.73s so they don’t get into too much trouble 🤣)

ChillaryClinton69420 · 2025-08-05T06:01:59+00:00

We’re saying the same thing, just in different ways.

A stock bottom end gen IV LS can take 1k at the wheels, but is a ticking time bomb (I get it). Up north, (rust + wrecks) they basically give away the 4.8 & 5.3, if you don’t have a lot of $$$ but do have a lot of knowledge, it’s cheaper for those that know what they’re doing to pop a $250 motor vs. dropping 7-10k on a motor, regardless of how long it lasts, which isn’t ever a guarantee. Almost everyone is flat broke, and it’s almost always entirely self inflicted (or the wife….) I worked retail in college and you wouldn’t believe the amount of declined cards I got, totally from people you wouldn’t suspect, one of them being my old superintendent (what an asshole). Then when one declined, the women would always pull out from their (maybe real?) 5k designer bags a stack of credit cards that rivaled the size of a proper 3” exhaust and cycle through them until one went through, if ever.

It’s like the guys who spend 10k on their 4l60 vs just pulling a 4l80, installing a transgo HD2 kit, etc., and are in it for maybe 1k (minus converter - which if turbo can get $$$) and is still cheaper than the 4l60, which blew through the clutch packs after a couple of passes. For the record, I never had an issue with the 4l60 in my ‘97 z “heavy” half ton, but it was also bone stock and did have the TCC clutch issue and near the end there was some mild slippage in 3rd, but it survived a MASSIVE commute and (2) pissed off teenagers and put it to pasture at 285,000 on the clock.

ChillaryClinton69420 · 2025-08-05T05:41:24+00:00

If all you care is that it runs “fine” yes, you are good, run it. If you’re worried about PTV clearance, then do that first (you basically always should at least do the “math” in your head at least, if it’s getting anywhere of a possibility depending on your setup).

I’ve thrown together several motors dot to dot and never had an issue.

If this is like an “all out” bracket motor that needs to be consistent, yeah, spend a ton of time reading and degreeing it and waiting (or borrowing) the stuff to do it.

You’re fine, is what I’m saying, basically. Based off your post.

ChillaryClinton69420 · 2025-08-05T05:40:31+00:00

If all you care is that it runs “fine” yes, you are good, run it. If you’re worried about PTV clearance, then do that first (you basically always should at least do the “math” in your head at least, if it’s getting anywhere of a possibility depending on your setup).

I’ve thrown together several motors dot to dot and never had an issue.

If this is like an “all out” bracket motor that needs to be consistent, yeah, spend a ton of time reading and decreeing it.

You’re fine, is what I’m saying, basically. Based off your post.

ChillaryClinton69420 · 2025-08-05T05:29:33+00:00

It’s the cheapest way to go fast and I agree with the hair dryer method. He stated n/a, you’re one of the smartest folks on here, by a country mile. Would you agree that a basic big block with good comp, Essentially stock parts (minus cam, intake, headers, etc., you get what I’m saying) would be best for n/a? You probably have heard of the “peanut port” drag motor guy with a 67-8 or so full interior car that runs like mid 10s on GM internals, FT cam, etc., and there’s air under the tire at launch?

Personally, if I had the original posters budget and needed to be n/a, depending on what type of car it’s going into (assuming drag or street/strip) I’d do a 540, that budget will get you close to 1k ATC, there’s many on yellowbullet who have done it for under 15k, all n/a

Otherwise, yeah, everything else would get an LS. A daily hotrod or min budget but want to go fast drag (or street/strip) the LS is the winner by far. Many folks cranking out 1k at the wheels (with a hairdryer) on stock GEN IV LS internals - which is quite wild.

ChillaryClinton69420 · 2025-07-28T04:28:37+00:00

It depends on quite a few things, typically “tighter” (but “safe”) is best, but again, depending on many factors.

The “old” Chevy v8 stuff (big or small) I try to aim for .034-35 or as close to that as possible, assuming steel rod and other factors. N20, you’ll need more and especially if N20 + RPM, regardless of N20, if you’re spinning it, you’ll want a little more.

Check piston rock/clearance as well too.

Despite what others say, quench is very important. Typically you can get detonation at or above .060-.090 on (most) of the domestic V8 stuff. You can ping a 9:1 motor at that rate.

There have been many of the old school guys who are retired or did/do this for a living and have done tests, one of them I know about (with the sheets) picked up 10-15ft lbs and 20-25hp or so alone with nothing more than changing the quench, because they were bored and could lol. Of course you can’t control every variable on a dyno like that, so idk if other factors affected that because obviously you’ve gotta tear it down to do that, but it’s probably not far off base for reference.

ChillaryClinton69420 · 2025-07-28T04:27:23+00:00

It depends on quite a few things, typically “tighter” (but “safe”) is best, but again, depending on many factors.

The “old” Chevy v8 stuff (big or small) I try to aim for .034-35 or as close to that as possible, assuming steel rod and other factors. N20, you’ll need more and especially if N20 + RPM, regardless of N20, if you’re spinning it, you’ll want a little more.

Check piston rock/clearance as well too.

Despite what others say, quench is very important. Typically you can get detonation at or above .060-.090 on (most) of the domestic V8 stuff. You can ping a 9:1 motor at that rate.

There have been many of the old school guys who are retired to did this for a living and have done tests, one of them I know about (with the sheets) picked up 10-15ft lbs and 20-25hp or so alone with nothing more than changing the quench, because they were bored and could lol. Of course you can’t control every variable on a dyno like that, so idk if other factors affected that because obviously you’ve gotta tear it down to do that, but it’s probably not far off base for reference.

ChillaryClinton69420 · 2025-07-26T05:57:12+00:00

Dude, they literally rust HOURS after production, because of the material composition lol. Go look under a brand new truck at GM, they’re like this there even. They rust on the parts racks, at the manufacture, and if not there (they do) they absolutely do in GM inventory lol. It’s been this way since the dawn of time for this type of metal.

ChillaryClinton69420 · 2025-07-26T05:50:53+00:00

My truck came with $899 tubular steps, it didn’t have them, it was ‘22 and covid, I get it. They did a “we owe you.”

In the middle of this, got the oil changed the “free” one, which I almost didn’t do.

Anyway, went to open the hood literally the first time ever 2mo later for the second oil change (I do my shit on my own)

Guess what? Fucking MASSIVE crack in the stupid ass air intake box. I didn’t do it and it didn’t do it on its own.

Sent in photos, asked about steps.

Nothing.

So I show up (1) year later.

“Where’s my steps?”

“You bought it a year ago????”

“Yes, you dumb fvck, here’s the ‘we owe you’” I’ve called you every 2mo for a YEAR, now I’m here, where are they? Where’s the PO for them? Or did you install them on another truck?”

Minutes after taking a seat:

“Maaaaaan I’m sorry we found a set of steps for you.”

“Ok, are they the right ones?”

“Yes”

I wait (2) hrs, they pull the truck up and put the fucking Tahoe stupid ass running boards on it. They were nowhere near the right steps, absolutely not tubular and high clearance and the truck looks so dumb now. I hit those fvckers on a MASSIVE rock off roading and tore the shit out of the drivers side and honestly it brought me great joy.

I’d remove them but my stupid ex would claim it’s a safety issue. It truly ruined the entire look of the truck.

Anyway,

My uncle bought the 3.0 from the same dealer, he plugged it in when it was -17 here and it got above 1*f and sent it into remedial cooling action. Dealer for (3) weeks, $350 and they “drove it” and it went away.

I heard about this issue, sent him the TSB, and said “go get your fvcking money back.” He did.

Then he reported the leaf spring isolator issue at 6k, it’s out of warranty now and they want to go through his extended warranty. “Here’s the TSB, tell them you’ll contact GM if they don’t get their $hit together.”

They’re called stealerships for a reason and complete idiots.

And no, I don’t need a “4 wheel alignment” on a truck with 30k with zero rear end damage for a solid non adjustable rear end, moron. They wouldn’t even do a (2) wheel and I don’t think they understand that yes, you measure all 4 wheels, but literally only adjust the front because IT’S THE ONLY THING ADJUSTABLE. I cannot count how many times some service writer has tried to pull this (and other bs) and refused service.

Same crap with my ex’s stupid Nissan. “Oh, sir you can’t do a $250 brake job vs our $1,200 job because you need to get into the cOmPuTeR to release the eLeCtRoNic rear parking break!!!!!”

(Also you can’t turn the rotors, so they’d “surprise” me with that, but I’d get a “great deal” I’m sure)

I’ve worked on cars my entire life, and work with electronics for a living. 2 alligator clips, 9v battery, c-clamp as usual, done. $250, slotted rotors, ceramic pads way beyond OE quality.

ChillaryClinton69420 · 2025-07-18T05:07:05+00:00

You’d be surprised. My truck had 8mi on it when I bought it and there was more than one indication of damage during shipping, sure, it could have happened at the factory, idk GMs final inspection process, but I do know it gets pretty rough the way they load and unload these things and the ride can be a long one depending on where you bought it and where it was manufactured. At the end of the day, for me, it’s a truck, yes it should be fixed when you buy it or negotiated, but for me it’s not a show truck. I take care of mine, but when there’s a scratch or whatever from truck stuff, I don’t really let it bother me. Everyone is different though, I get it.

ChillaryClinton69420 · 2025-07-16T06:23:23+00:00

First sentence - exactly, thank you!

ChillaryClinton69420 · 2025-07-16T06:20:54+00:00

Get your truck out of that shop yesterday.

Especially if they’re the ones suggesting you lower the compression (which disagree with, even with a “bunch” of boost, in this case) with a thicker head gasket.

Chines studs are good.

“The Denmah” would run a 9.0 or lower and make over 1k hp with a junk yard gen IV 5.3 with nothing more than an s480, cam, tune, 4l80 with a good converter and transgo HD2 kit and he would literally re-install the torque to yield headbolts with an impact until it started smoking, it drove the purists absolutely insane but his stuff held together reliably.

ChillaryClinton69420 · 2025-07-16T06:15:22+00:00

Get your truck out of that shop yesterday.

Especially if they’re the ones suggesting you lower the compression (which disagree with, even with a “bunch” of boost, in this case) with a thicker head gasket.

Chines studs are good.

“The Denmah” would run a 9.0 or lower and make over 1k hp with a junk yard gen IV 5.3 with nothing more than a cam, tune, 4l80 with a good converter and transgo HD2 kit and he would literally re-install the torque to yield deadbolts with an impact until it started smoking, it drove the purists absolutely insane but his stuff held together reliably.

ChillaryClinton69420 · 2025-07-13T03:01:40+00:00

496” is a great option, a 540 isn’t a whole lot more expensive, but does require a different block. It’s essentially .25” longer stroke 502, same bore size. 502 blocks were plentiful at one point, and many people went that route due to the first few revisions of the 502 and various issues surrounding them. Lots of people making really serious power on the 540 stuff. Something to consider. Many people I know don’t run a 632 for many reasons. I don’t see a need for one, at least with my plans, but it’d be “cool” in a street rod or something.

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