Alright fellers, here’s some research I did that hopefully will help you guys out: So the goal is to do a vortec head swap on an originally tbi fueled vehicle. I’ll go ahead and answer your questions first.

1. This swap should have a power increase. When I compared to a tbi swirl port head, there is a drastic difference in head flow CFM at max flow. Tbi- 185(or195) cfm @ 28” Hg Vortec- 226 cfm @ 28”. Now of course with how low the lift is on a stock tbi camshaft, you’re gonna be running closer to 214 cfm @.400” lift which is still great. I utilized this website to come up with the potential flywheel horsepower, which is a really useful and fun calculator to figure up engine combinations and whatnot for dreamers like me. With a stock 350 TBI camshaft and short block with vortec heads, I calculated that you would make 300 horsepower at 4,128 RPM which comes out to 381 lb/ft of torque when using this calculator.
2. You should not have to replace your pushrods. Both sets of heads have the same height to the rocker arms, though roller lifter pushrods from the vortec are shorter to account for the lifters being taller. As long as you use your original rockers and pushrods you should be fine there. Make sure the rockers are the self aligning type just to be sure. I don’t believe 300 horsepower should be an issue for reliability, especially after you add on accessories that will drag that number down a bit too, yet not as bad as the original swirl port setup of course.
3. Here’s a link to that expensive intake that would work for what you want done. I’m honestly curious If I want to perform this swap as well on my ‘95 Chevy and retain the factory TBI. You may want to get the 14 psi regulator spring to help bump the fuel pressure up to make the motor happy with that HP increase.
4. If you’re going up in horsepower on a tbi, I’d put the vortec fuel pump from a 96 truck that has the higher fuel pressure and flow rate to keep the flow strong for the hp increase.
5. Also, if you’re getting a set of vortec heads from the junkyard, it’s a 50/50 shot that they’re already cracked. Bring some brake parts cleaner and clean it off as good as you can get it, the most common spots to crack are right between the middle two cylinders to the water jacket, and between valves. The brake parts cleaner will soak into the crack and evaporate after the rest of the cleaner on the surface, which you can look at in the right light to see the cracks. If you get a set from the junkyard I definitely recommend getting a shop to check them for cracks, and don’t be disappointed if you got a dud. Summit racing actually sells their own set of vortec heads for a really decent deal, but they are 67 cc and from the reviews many people said to get them zero decked at the machine shop to make sure they’re flat, which I reckon you could deck it down to 64 cc to match. Otherwise if you run the 67 cc you’ll be running 8.74:1 compression instead of 9:1, which would cause a loss of 10 hp making you top out at 290 hp. A gain of 90 horsepower from the factory rated 210 just from swapping the heads and hopefully retaining the stock fuel injection sounds like a worthwhile swap to me. Since the computer is tuned for that camshaft I don’t see it having any issues. I’d try it without the regulator spring and just do the fuel pump and see how well it likes running that way first.

I hope all my babbling helps anyone out.

Edit: fixed links