jccog
NAXJA Forum User
- Location
- Albuquerque, NM
I just took my HO 4.0 head to the machine shop for rebuilding. I ported and polished the head myself and found articles on how to CC a combustion chamber, so I checked all 6 chambers before it went to the machine shop and measured ~ 56ccs. I told them to mill off .015" so I could increase my compression. I was trying to get my CCs down to about 53-54 ccs. Well, the head came back and the chambers are now 57-58 ccs. I called the shop back this morning and had the manager ask the machinist who worked on it how much he took off and he insists it was .015" as instructed. The shop is well respected for their quality. What's going on? Could the valve job sink the valves that much? They did have to replace 2 valves (1 int, 1 exh; because I ruined them while porting) and the chambers with the new valves are measuring around 56.5-57ccs and they do appear thicker than the old valves.
I'm tempted to replace all the valves and mill an additional .010" off. Should I have them mill more off the head? Will this cause problems with the pushrod length? I don't know how forgiving the hyd lifters will be. I'm already using the MP head gasket (.042"). I am also using the Comp Cam 68-232-4 cam and lifter set.
Thanks in advance!!
I'm tempted to replace all the valves and mill an additional .010" off. Should I have them mill more off the head? Will this cause problems with the pushrod length? I don't know how forgiving the hyd lifters will be. I'm already using the MP head gasket (.042"). I am also using the Comp Cam 68-232-4 cam and lifter set.
Thanks in advance!!