[DeTomaso] Quenched Head Rework or Tweaks???

[JDeRyke at aol.com]

In a message dated 1/3/09 2:17:44 PM, tborcich at msn.com writes:

> My heads are cast iron. Lets say you go with a milodon valve like what you 
> have, a 500-575 lift cam max for both intake and exhaust. From what I've read 
> 125 seat pressure and 350 open pressure should be enough. Did I miss 
> something? Currently my cam is 498 intake lift and 510 exhaust lift...
> 
Similar to my cam. But don't forget, all this seat pressure stuff is also 
rpm-dependent. The whole idea is to pick a redline, select materials to hover 
close to it without exceeding the limits you set for yourself. I don't venture 
over 6500 rpms with my combo and that's proven to be a good guess so far. But 
stiffer springs for more rpms or to control heavier roller lifters on those 
necked-down Megaflow valves may not work as well. 
Sometimes, we skate REAL close to the limits without realizing it. Early in 
'08 one club member put a crate 302 motor in his autocross car, tried it out up 
to 6500 and everything was fine for a couple of events. So he moved his 
rev-limiter up a tad to 6850 rpms and cracked the rear end of the block clean off, 
along with the last two throws of the crankshaft.... Think he said something 
about ...'I didn't even get 90 days...' FWIW- J DeRyke




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