Another Compression Question

[Stratplexi]

What is the compression for a 95" BB with Flat tops if milling the stock heads by .050" ? The SE book says the Flat tops are 9.4:1 with stock heads and I assume that is with standard gasket thickness. It also says the compression with SE heads and the Flat tops are 10:1 and I believe they are milled .060".
Therefore, I would assume that if the heads are only milled .050" it would result in something less than 10:1.

BTW, anyone know the standard gasket thickness and the Cometics?

Also, been talking to a shop that does a 5 angle valve job on stock TC heads and they claim an approximate 10% power increase just from this 'clean-up' work. I think they also stated they change the valve seals and guides while they are doing the job. They do this and mill the heads for $100 each head. Sort of a cheap way to pick up some power. Does this sound correct?

Thanks!

[HDMD88]

Originally Posted by Stratplexi

What is the compression for a 95" BB with Flat tops if milling the stock heads by .050" ? The SE book says the Flat tops are 9.4:1 with stock heads and I assume that is with standard gasket thickness. It also says the compression with SE heads and the Flat tops are 10:1 and I believe they are milled .060".
Therefore, I would assume that if the heads are only milled .050" it would result in something less than 10:1.

BTW, anyone know the standard gasket thickness and the Cometics?

Also, been talking to a shop that does a 5 angle valve job on stock TC heads and they claim an approximate 10% power increase just from this 'clean-up' work. I think they also stated they change the valve seals and guides while they are doing the job. They do this and mill the heads for $100 each head. Sort of a cheap way to pick up some power. Does this sound correct?

Thanks!

Bullet is the one who can answer your questions on compression ratios with milling the heads.
As far as some one telling you that you will gain 10% more power from a 5 angled valve seat is crazy. What they are saying is if I had 100hp and they put two more angles on a stock valve job you will get 10 more hp.....please give me their number....I will use them in ever build I do......NOT!!!! We can pick up a little hp by cleaning up the last inch of the port and doing a nice blended valve seat but not 10%.....thats a bit far fetched.

[Stratplexi]

Originally Posted by hdmd88

Bullet is the one who can answer your questions on compression ratios with milling the heads.
As far as some one telling you that you will gain 10% more power from a 5 angled valve seat is crazy. What they are saying is if I had 100hp and they put two more angles on a stock valve job you will get 10 more hp.....please give me their number....I will use them in ever build I do......NOT!!!! We can pick up a little hp by cleaning up the last inch of the port and doing a nice blended valve seat but not 10%.....thats a bit far fetched.

Thanks for the quick reply and frank comments. I think my post is a little misleading and I need to clarify what they claim...approximately 10% power increase over stock heads. This was in the context of a Stage 2 BB build with a bolt in cam. In other words, if I let them 'clean up' the heads I could expect an additional 10% gain in power vs. doing nothing to the heads. I thought it sounded a little 'far fetched'.

Thanks again for the help.