Okay so what size of valves should I have in the cylinder heads for a 350. I am planning on putting a 350 in my trans am and am going to put aftermarket heads, cam, and headers on.

 

Standard size valves for aftermarket heads is 2.02 intake and 1.6 exhaust.

 

A 2.05 intake can be used but I doubt you're anywhere near a power level where the even larger intake is necessary.

 

Well I already have a flowpro muffler a eldebrock intake and carb for a 350, with a cam, headers and cylinder heads it should be around 380 - 400 horse.

 

stock is 1.94/1.50

 

Very few aftermarket heads come with the smaller valves unless specially designed for the small bore of a 305.

 

So then do I want 1.94/1.50 or 2.02/1.60?

 

2.02/1.6

The smaller vavles are for a 305. No reason to build a 350 and put stock sized small valved heads on it.

 

Stock 305 valves are 1.84/1.5
Stock 350 valves are 1.94/1.5
That's what he said above "stock".

Standard aftermarket 350 valves are 2.02/1.6 This is the norm, and is fine.

 

Agreed. 2.02/1.60 is typical for aftermarket 350 performance heads and works just fine on most applications.

ADDING bigger valves to stock heads, however, is a dicey proposition. Usually not worth the effort or expense vs. just buying aftermarket heads.

What heads are you considering buying?