How much compression will be lost if I get a set of heads with a 69cc chamber volume (I currently have 63cc chamber volume). Does compression lost lead to performance lost? If so how much? The valves are 1.90x1.60 on the heads that have the 69cc.

Every 5cc is 1 compression point.You loose a bit of power but not enough to cry about


Tom...www.tkmotion.com....514-920-0094....Making power is what we do best!

I am not sure which heads you are dealing with, however, milling is an option also. Depending on how much material you have to work with on the surface of the heads, milling them and consiquently making the chambers smaller, will help make up a lot of that difference.

The heads Im reffering to are from Aerohead. THey dont have a web site but they have an add in the MM&FF magazine on page 245 in the latest issue (March 2002). This is what the ad says:
Assembled Ford Casting
Like new appearance surface milled
3 angle valve job - bronze wall liners
Stainless 1.90x1.60 Valves
New Umbrella seals, locks, and retainers
New .550 lift springs
5/16 pedastal rocker mounts standard
69cc Chamber Volume
$399.00/pr

Im on a budget and trying to find a nice set of heads were Im gonna AT LEAST gain 30RWHP and about 20RW lbs of torque. Just with those heads about how much gain will I see??? I have a list of other mods Im gonna be doing also. Im either going to get those heads, GT40s, or Powerheads.