resurfaced heads

[OIL BURN]

Had heads rebuilt with new iron high nickle guides, exhaust seats,valves,springs. The machine shop that did the work,recommended by the local chevy dealer,sent the heads out to have four precups replaced. Problem is they pinned the precups in place then shaved them. This was five years ago and i finally decided to assemble the motor. Time to put the heads on, i tapped the precups to insure they are secure and two dropped down .005, not good. Now have new precups, will machine pockets to fit .001 above surface. Measured head thickness, it measured 3.823. Several shops stated 3.853 is factory standard and should not be shaved more than.010. Well , heads are shaved .030 ,measured several times from valve cover gasket machined flanged to milled gasket surfaced. Has any member run heads milled this much with success. These are 14057299 fine thread heads, year 1983. Welcome all input, thanks to all members and the diesel page.

[sctrailrider]

I don't think that would be a good thing if they are really cut .030, that would put your valves on top of the pistons or really close, and the comp ratio wayyyy up there. i would think I would cc the head verse a stock head to see what the difference is. as for the cups, that might be OK, don't know for sure.

[DmaxMaverick]

A .030" cut is OK. Make sure you use +.030" head gaskets. They were hard to find for a while. Maybe more available now.

[john8662]

Cut heads won't really raise the C/R because there isn't a combustion chamber (beside the precup chamber) on these heads.

I've run some shaved down quite a bit.

The key to clearance is that the valves have to be machined into the head further on the seats to keep the right clearance.

I'll have to dig up the minimum clearances. The books all have the maximum valve recession depth, but not the min.