I have a set of prc stage 1 ls6 heads. They have to be milled .010. What cc would they be after doing that? Thanks for any help so I know what more specs to order a cam.

 

measure

 

They are 64cc to start so 63cc afterwards in theory. It's .008 per cc. As Pred-Z mentioned, measure to be 100% sure.

 

You'll be right about 63cc, assuming your .010" mill number is correct. They started about 64.5cc or so before milling. Compression ratio calculations round and about half the measurements are guesses at the DIY level anyway....so 63cc chamber volume should do the trick for you (unless you're measuring everything else, and then you'd be measuring this too and not posting the thread).

 

If this head is CNC'd then they will end up bigger than 64.5cc (stock size). Unless you guys do not touch the chamber at all.
So the only way to say how much they will end up at is to measure after mill. All else is just guess work.
Op, if you want to know the truth, the only way is to measure. Personally I think TSP could cut you a nice deal and measure for you, their customer service is supposed to be awesome...

 

PredatorZ we do not CNC the chambers on our LS6 heads at all. What Matt said should be pretty close. We appreciate the kind words.

 

The LS6 chambers are not CNC'd. The LS6 heads have been around long enough that it's pretty well known they start about 64.5cc, and you can use .006-.007" of milling per CC of chamber volume. Like I said, if this was a delicate scientific calculation for a pro-stock team and not the average do-it-yourselfer, he would have already measured himself. 63cc is going to be very close and will suffice for his calculations.

 

I know you do not CNC the chambers. But usually a porter will do a once over the chambers and reduce spark plug hump area (this is why I said unless you guys do not touch the chamber).
And Matt, perhaps we sometimes do not see eye to eye, but seriously, the pro-stock comment is weak, very weak.

 

The pro-stock comment was more a metaphor that someone on a higher level that needed closer measurements, like a pro-stock team, would have measured instead of making a thread asking.

 

Ok i dont have anywhere close by to measure. The machinist couldnt do it. He basically milled them down and no he didnt touch the chambers. Reason i was asking mainly, was because i had a ms4 cam and now i need to spec a new cam.

 

I know I need to measure, just i figured there was a formula for it. I will measure once i get a cam spec'd

 

More important than the chamber volume, now that you have milled the heads again (they get milled before they leave here) you would want to measure the valve drop. That is how far the valves travels from their seat to a table top or your piston at TDC. With that measurement, we can compare your drop to stock and know about how much room you've given away, and therein about how much camshaft you can fit without having to cut the pistons!

 

Matt I mnow this is gonna sound stupid, but on a table top how would I go about measuring that? I've been thinking about going with your torquer V3. I already have your. 660 valvesprings. I mainly need a cam, lifters and pushrods. Thanks for any help, I've bought everything from you guys and would like to get more from you.
Thanks, James

 

You'll need a dial indicator and some sort of steady mount so you can put the tip of the indicator on the valve tip. Then with a checking spring or no spring you measure it from the seat to table or piston.

 

http://www.compcams.com/catalog/COMP...12_379-380.pdf

That kit#4942 has the stuff you need AND the degree wheel so you can degree your cam and check piston to valve clearance accurately after install, too!

 

Ok thank you. I will get that ordered