I will be installing a cam in my '02 firehawk soon, its specs are 238/244-.605/.610- 114+4 with ported 202/157 - 243 heads, unmilled just cleaned.. My builder/tuner says it will be fine, what does anyone else think???

 

Sounds REALLY close. I think you'll have to clay the piston to see what you have after it's installed.

 

It might not hit but the ptv minimum will probably not be there. Are you going to use a .051 GM MLS head gasket?

 

I'd get ready to flycut!

 

Forgive my ignorance but if thats what stock GM gaskets are then yes, thats what i had planned on using..

 

i'd start making arrangements to cut. that being said you might as well mill and get your money's worth....

 

TBH you are really going to need to test it out with clay. The lift isn't too extreme but with the duration you are looking at the transition from exhaust stroke to intake stroke will bite you in the ***. If it were a say 226/230 cam with the same lift you'd probably be close but safe.

 

the lift has nothing to do with PTVC...

 

So. . . . what you're saying is the movement of the valves in relation to the movement of the piston is irrelevant? Granted timing is a part of this, but if the total movement of the valve can intersect with the total movement of the piston, then I would be concerned with PTV clearance...

 

I don't think nothing is the correct word. Maybe "is not the sole reason for PTVC issues"? A .490" lift I would image could allow a couple extra degrees of duration when compared to a .600" lift cam.

 

you are right I meant to have the "little" in there...



where is the piston when the valve is at max lift...duration is the king along with split...

 

Do yall usually flycut for your PRC LS6 2.5 and MS3 combos?

 

Well with all the controversy I will definitely be checking before final assembly. Since i dont know exactly what has been taken from the heads, it will be better to be safe than sorry, especially since so many people are on the edge or ARE recommending cutting... Thanks for the input!!

 

If we setup the Stage 2.5 LS6's specifically for the MS3, we can make it comfortable to run, albiet still tight. But on your run of the mill ported LS6 head with 2.02"/1.57" valves, some random machine shop's valvejob, etc I will go ahead and bet the OP needs to flycut.

 

agreed, id be ready.