Decking Head Question

[PCGUY112887]

I was wondering something, lots of people get their heads decked, either for more power through the higher compression ratio or just to ensure their flat (or both). Well it seems that if you deck them making them a tad bit shorter, all of a sudden the LIM and exhaust mani's woulden't align correctly?

[geoffinbc]

Intake can be a problem if you take too much off. But usually if only enough it remove to clean up the head your fine. But if it comes down to it the machine shop will also need to machine the intake.

The exhaust manifolds are usually not a problem at all since there is plenty of play in the exhaust and the flex joint on the rear manifold.

[PCGUY112887]

Is it worth it to have them decked as much as I can for a higher CR then deck the lower intake or just leave it?

[Blackrider]

I had mine deck .020 and never ran into an issue with anything lining up.

[PCGUY112887]

Does the extra compression help at all? Could decking .020 bring me to 10:1 or higher?

The way I figure is if i'm going to have them decked to be level then I should just have them decked for best performance.

[1988GTU]

You could also look into changing pistons for more compression. It would get costly, but you would not have to deck the heads as much. Then put in a hotter cam. You'd have high output then.

[PCGUY112887]

Yeah if I had more money I could

[PCGUY112887]

Anyone with some of those uber engine specs at the top of their head care to tell me if decking .020 is safe (still enough clearence for the pistons at high RPM's, etc).

[SappySE107]

Decking the heads doesn't change the clearance for the pistons. Only the block decking will affect that. I drop about 1 cc with a .020ish deck, so don't expect 10:1 from just that.

[geoffinbc]

Don't be under the impression that compression will make power. Go to crazy and you will run into detonation problems or early pinging which will retard ignition timing. Be aware of the fuel you choose to run, your cam specs, ignition timing and ECM programming. If you want to tear your motor down and run a cam optimized for more compressiona nd hten have hte ECM tuned accordingly then go ahead and have the compression increased into the high 10's or so. Otherwise clean up the heads and bolt everything back on and you will be better off.