[Rob H]

I have decided to keep the GM heads I have instead of buying new ones. I don't race the car, but want the feel when I take it out. My question is, what all should I have done to the heads? The engine is a 396 in a 68 Chevelle. It has stock crank and 10.25 pistons, Lunati cam (235 @.500, 525 lift, 2200-5500 range), Holley street dominator, Holley 750 vac, headers, 3in exhaust with Flowmasters, TH400, 12 bolt posi w/3.90 gears. I have been told a 3 angle valve job and new seals is all I need. It has new springs and roller tip rockers. After installing them it started blowing smoke at startup, plus all eight plugs were coated with oil, hence the need for head work. I assume the valve job is all I need. Should I put new valves in at the same time? Also, is the Holley manifold ok or should I go with something else. The cam seems to match the specs of the Edelbrock Performer RPM. Should I switch to the Performer RPM manifold? Any tips would be appreciated.

 

[Gene Chas]

Rob, all you need is what the heads need. I mean if the guides are worn, then you'll need to line them. Don't replace parts unless they're not servicable. Check the valves for excessive wear and to see if there is enough meat left on the head to clean up nice. I suspect you might have some worn guides. It seems common to reline them during a rebuild.

Alot of my rat head friends have had trouble with the umbrella seal. I would go with the teflons which require a simple machining operation to install. Incidentally, some of us don't bother running seals at all on our exhaust valves. There have been incidents of valves seizing in the guides. For a street motor, I wouldn't sweat it though. You always get a puff on fire up.

Pocket porting, as it's called, is a nice way to get a little cfm gain out out your heads. It's just a simple clean up of the area just near the seats.