I have a set of 243 heads off an 05 vette. I also have a set of cnc ported 241heads that are junk( ported into the water jackets) But the 241s have rev 2.02 1.57 stainless valves.. And comp double springs and all that good stuff .. Im really on a tight budget ....
So the plan was to just have the 243 heads milled a little to bump up the compression. and run them with the stock valves.. My machine shop said they could also do the valve job and swap the larger valves in and do a little bowl blending for a nice gain in flow..

Its going on a 2000 c5 m/6 stock bottom comp 228/232 588/595 on a 112 installed straight up

So the question being will there be a big advantage to swapping the bigger valves in or just stay with the plan and run the stock valves just swapping the double comp springs on??

 

anyone

 

i say go for it. swap the valves after its cnc ported

 

I am wonderin the same thing....On the GMPP high compression heads on a 5.7, what is the max lightests valves i can fit on them...

I have 2.100" hollow intake valves from Katech but the exhaust valves keep eluding me. I tried to find 1.590 from the LS3 but no part numbers are available. i will settle for 1.570 but sodium filled. i like to rev my little block...

The GMPP heads can flow, its just they are held back because of the valves.

 

?

 

The quality of the VJ will be the biggest factor in your gains but all else equal yes bigger valves will help.

 

You can swap your valves no worries...But CNC the runners before you reseat the valves. This way you will take full advantage of the valves...

2.020 and 1.570 is a very good mix....