turbo head and valve options???

[skylinedriver59]

Hey guys!

I haven't been on for a while and that's because I haven't touched any of my projects for a while. But long story short i'm getting some work done to my L28ET and want some advice?

Here is whats getting done; the bottom end is getting ROSS forged pistons, using stock rods but rods are getting shot peen, crank is being balance and grind. Using new racing bearings and ARP mains and rod bolts.

now to my problem the HEAD, I have a P90A head but my machinist is telling me the fact that the head has hydraulic lifters is going to limit the power I'm looking for. So we talked about doing the lifter conversion but his not a fan of the conversion. So I started looking for a P90 head which I'm going to pick up today. Here is what is planned to do to the head; new valve springs from Motorsportauto, tomei cam gear, cometic head gasket, schneider cam, and SS valves all that on a ported head. Now everything was on order but I got a call yesterday about the valves no valves are available until maybe late February.

So my question is do I really need valves? I am not using over size valves so can i do some kind of conditioning or strengthening work and use my stock valves?

will the P90 with solid lifters and a crazy cam really make good power?

thanks guys

D

[evildky]

What are you power goals? What is the porpose fo the car? The recipe to a max hp dyno quees differs form a drag racer which differs form a road racer which differs form an autocrosser, street cruiser etc.That bottom end should be goot to north of 600 whp, the stock head with hydraulic lifters and can rarely sees north of 400 whp, with a mechanical head and a properly selected cam grind the mechanical head with stock valves and lots of port work can see 600 whp. Braap (Rusch motor sports) is the L6 head guru but he isn't cheap, figure $2k and up for a braap head job. I know you can oversize the valves but your goals might not need it.

[skylinedriver59]

My goal is 500+hp and the car is going to be most likely a drag car. So stock valves should be fine. can valves be heat treated for strength?

[evildky]

500 at the crank or at the wheel? At the crank you might be able to skate by, for 500 whp that head will have to be worked. Oversized valves will help but the head only has space for very small improvement, +1mm intake and +2mm exhaust or vise wersa IIRC. Port and polish as well as combustion chamber work are also needed to reach this level of power.