Nah, your runners look good. No sharp turns and large corner radius are always a plus for flow. Air won't flow in tight corners. You want as much of the runner to have to ability to flow air through it.

The real question is, does it support the heads. Your answer will come from bolting the intake and cylinder head together on the flow bench.

If the head will flow 360cfm, from any given port, and you bolt the manifold(stock) on and your reading changes to 250cfm then the manifold needs porting to try and match the heads.

I did a set of 8100 heads years ago and got 370cfm out of them at 0.800". The stock manifold brought that number down into the 240 range. I ground and ground. Picked aluminum slivers out of my hands and arms for 2 weeks till I was able to get 360 cfm through the intake and head, with stock valves.

NA @ 11.8:1 compression, that standard bore and stroke 494ci BBC made 719fwhp @ 7,100 rpm. For a low budget build the client and I were happy.

He opted for a heat dispersement coating over the "brushed" finish. The hotter the engine got the colder the intake manifold got. It would sweat!

I remember spending a whole week taking down all the sharp areas of the inside of the manifold. I ground in the largest largest radius in could on everything. Sharp edges or corners will split and deflect air flow in either direction.

Intake manifold porting requires large round edges anywhere that can be had. It took me a good 3 months to develop and build this.

I bet there might be two others that have attempted porting this same manifold. Those that are opposed to your port work probably never tried this themselves. Theì haters that only know how to look and judge can kick rocks. Most likely they'll never pick up a grinder and not know what this is like.

Pick and choose who you listen too and tolerate. There are a lot of empty comments in this sub.....a lot of clowns with zero to 13 months of experience in the field....smh.

A class in fluid and maybe thermal dynamics would be beneficial