I have a 77 280z. I've heard that using thicker than stock headgaskets can raise compression, giving more power. Is this so? Where can I find a decent headgasket? I know those 1mm HKS ones are out there for 100$ but I don't want to spend that much. Everything on the car is stock except intake and exhaust. Thanks

Tony

 

to get higher compression, you don't use thicker HG....your suppose to use thinner HG. thicker would only lower it= less power.

 

yah, a thicker head gasket would make for a slightly larger combustion chamber, because it would be taller. that would lower compression. you want a thinner head gasket. people frequently mill their head (shave aluminum off the bottom) to make it shorter, which gives higher compression. milling the head also gives it a smooth bottom surface so it mates better with the gasket and the block

 

How much could I shave off? Would I need to get a machine shop to do it, or could i do it with say a file, then clean it up with sandpaper and the like? Also, how thin of a gasket could I use? Thanks guys

Tony

 

the most you can shave off is 10 thousandths without needing cam tower shims. if you shave more than that, you will need cam tower shims.. this is to have right tension on chain and timing marks.. hope this answers your ? about shaving the head.

 

You can shave it up to 80 thousandths. Always have a machine shop do the work. You will never be able to shave the head with a file.

You don't have to put in cam tower shims but that is the safest way. You may install a new timing chain set and advance the upper cam sprocket to the #2 or #3 position to begin with. This will compensate for the shaved head putting slack in the chain. Notch the curved chain guide bolt holes and shove it up against the chain to take out some slack. The timing chain tensioner will do the rest. Change the set at 100K miles or sooner.

With intake, exhaust, and higher compression, putting in a performance cam will really benenefit you. You'll get the full potential from it. The only thing left to do is port the intake ports on the head and the manifold.

 

yah one of the primary purposes of milling the head is to make the bottome of the head flat.. as in one perfect plane, all level, and smooth... i would shoot anyone who even TOUCHED a file to my cylinder head.....BIIIIG nono