ok guys here is the deal i am building up a 355, forged crank, rods, pistons, aluminum L98 heads, 10.5-11.0 compression, crane cam with 1.6 rockers to make the lift .498 .513, headers, 2800 stall, ported intake, adj fuel regulator, and about every free mod there is, now what size valves should i use. no matter what size i am getting manley RACEFLOW valves but still stuck on 1.94/1.50 or 2.02/1.60. i heard some where that 2.00/1.55 or something flowed the best but asking opinions dont really have the cash right now to get new valve seats but yet i am not drivng it so i could wait........ please post up

 

no help? come on guys

 

i could be wrong(someone correct me if i am) but the 1.94/1.5 valves are stock valves. with your engine and combo you should deffinatly go with 2.02/1.6

david

 

I think the reason people go with the 2.00 and 1.55 are to avoid replacing the seats. Pretty sure 1.60's work on the exhaust ok though.

 

please explain.... i wouldnt need to change the valve seats?

 

2.00/1.55

any bigger and you run into valve shrouding problems within the chamber itself

 

ok yess but would i need new valve seats?.... i think i am gonna stay with the 1.94/1.50's if i want to go bigger i will pull them back off.... dont drive it every day so u live and learn

 

There are quite a few heads with small valves that the seats are way too narrow to accomodate such a large change in valve size. I'm pretty sure you cant put 2.02's in a vette head without replacing the valve seats.