scorciae

i have 1980 L48, i am changing the cam soon but dont have enough for new heads. i figured since i will have the heads off anyways, and my friend owns a machine shop i would try milling my own heads a bit. i was wondering how this is done? do i take a uniform amout of the whole bottom of the head? also how much do i take off and what else needs to be done with it, also what would my compression increase be with that and a thin head gasket?

Pete79L82

Those are lightweight heads so you have to be careful how much you take off. With a 76cc chamber you will reduce chamber volume approx. 1cc for every .006 milled off. I would be real hesitant to take of more than .020 with that head so you will only reduce volume by about 3.5cc's. That will amount to about a 1/4 point of compression.

With a lightweight head it is not recomended to angle cut them so you will have to take a uniform cut off of the entire gasket face on each pass.

You will have to check intake manifold alignment after you after you are done to be sure that it doesn't need to be cut also.


You don't have to remove the heads to change a cam and I would recomend waiting until yoou can afford a better set of heads. Change the cam now, pull the heads when you can afford different ones.


[Modified by Pete79L82, 7:28 PM 3/10/2003]

1979toy

Using a thinner head gasket like the Fel-Pro part number 1094, which is a .015 thick gasket, will help you raise your compression ratio also.
Having your heads angle milled will increase your compression ratio more than a straight mill. Find a machine shop that is familer with doing this as it's a tricky job to figure the amount to cut the intake to match the revised heads.
By the way, all this machine work will cost as much as an aftermarket set of heads.