What size valves for boost?

[jaffaz32]

I'm going for a 3.4L stroker kit coupled with a LoveFab GTX turbo kit. Aiming for 540whp.

I have been reading lots and decided to go with Ferrea valves but they come in 2 sizes on both intake and exhaust.

My motor was originally a 3.0, the smallest they offer is stock 3.2 size i believe and also go one step bigger, 1mm over stock 3.2 on both intake and exhaust. This is just the conclusion i have came to reading spec sheets and making a understanding of them.

Here they are:

http://www.nopi.com/dsp_parts_16.ph...=155&vspc=Engine Compartment > Valve - Engine


I'm assuming the stem is the same size as stock? so can i use normal size stem seals?

What are the advantages and disadvantages of bigger valves on a boosted engine?

What size would you go for with my setup? Both intake and exhaust?

Thanks.

 

[jaffaz32]

The engine builder said it's a difficult question to answer. Generally bigger is better but he's asked to see the heads prior to see what would flow test best and i'm guessing fit.

I'm going to make an assumption that it's a case of what space there is to play with because surely if the 3.2 valves are bigger than the 3.0 and i'm going to a 3.4 and pushing more air in to the engine anyway from FI then surely additional 1mm is a good move.