max lift

[lyonsy]

hey
just woundering what the max lift whould be for a 200/221 pre xflow with a soild cam 500? 600?
drift

 

[addo]

With a fairly stock head, you're likely to run out of real benefits over about 480 thou. Actual max lift possible would be greater but you also start to severely stress your valvetrain. Crow's cams are a conservative guide to how much lift is viable; check out their specs for the sixes.

Cheers, Adam.

 

[lyonsy]

hey
so where does that leave the new alloy head that makes its best at 600 thou liftthats about 2.5mm more lift
drift

 

[addo]

I said a fairly stock head. That means a non-2V that hasn't been massively worked over. Valve train stresses will still be there with the new head.

 

[lyonsy]

hey
so you whould be looking rollers double valve spring with good collets and retainer's
also the us 200 block is the same as our 221 block correct?
drift

 

[addo]

The US 200 block is sort of more compact. Its cam is closer to the crank. I have no idea on comparisons of cylinder wall thickness and block rigidity.

A build is best when structured to take advantage of the motor's natural abilities. If you wanted a huge lift with decent engine life, roller cam conversion might be to consider. But yes, for higher RPM and big lift all the same basic concepts apply as to any motor's valvetrain - stout parts.