PTV, head milling, compression and cam choice
Thread Starter
Teching In
Joined: Oct 2023
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PTV, head milling, compression and cam choice Hey guys I'm new here and have found a lot if good information on here. I'm building an L59 5.3 for a 2007 GMC Sierra 1500 Classic. The machine shop has redone the whole thing. I'm putting it back together and I am doing flat top pistons in it, a small Callies Stage 1 truck cam 210/218 on a 108 LSA and am wondering if I will run into piston to valve clearance issues. I also found out the heads need to go back to the machine shop because a family member moved them and gouged the freshly surfaced head surface. I'm worried because the heads and block were milled to be flat compatible surfaces so they had material removed from both sides and now more will have to come off the heads and I don't know how much they took off of each surface the first time. Anyone have any ideas on if I'll be okay to run that cam now and what my compression would be?
TECH Senior Member
Joined: Jun 2016
Posts: 22,293
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From: Central Cal.
The head and block surfaces never "see" each other. A gasket separates them. The type of surface is totally immaterial and do not need to be "compatible". Just a good smooth flat surface that the head gasket can seal is all that's needed. If it's only a scratch, that can be taken out without machining.
How did the machine shop "redo" everything??
The cam is pretty mild except for the very narrow 108 LSA. That only allows a -2 overlap. It WILL lope! A 112-114 LSA is more common.
How did the machine shop "redo" everything??
The cam is pretty mild except for the very narrow 108 LSA. That only allows a -2 overlap. It WILL lope! A 112-114 LSA is more common.
