just read jap performance last night ,in the rcm advert/article they say the oem manifolds can reach 370bhp but no more,is this true for newage cars or just classics as hopefully plan to turbo upgrade but do not want to change manifolds at same time unless needed so i can work out the gains on a turbo alone
martin

 

fairly sure AndyF managed 400 on his.

 

would that have been a ported set David?
I know that a few of us made over 300 after Harvey had ground the **** out of them.

 

i am still unsure as someone i know has a similar car sti8 with aftermarket manifolds/td05 06 20g turbo and gets 365bhp(tuned for more torque) but how far would you get with oem manifolds as he did all his mods in one go
martin