Head work advice

[ec_co]

Strange how circumstances can change in just a couple days.

I'm dropping off my '70 head for a rebuild and need a little input.

Oversized valves - I've seen several different builds using different OS valves, but can't seem to find any specifics. Just so that I can give my guy some exacts, please recommend an exact size & brand (part number would help as well too), I just want to make sure we get the right thing the first go around.

Milling - what is an acceptable amount to shave while retaining the stock lower end short block? I want to bump the CR up a bit, but I may not be able to get the measurements for the lower end for an exact CR, but a safe bump would be nice.

He'll have Doug's recommendations on head work (chamfering, extra oil hole, 340 springs).

Anything else I should have him do or check?

The build thought is currently - Dutra RV10 RDP cam, offenhauser 4bbl, Edelbrock AVS2, Clifford headers for 3-2-1 exhaust, JP billet timing chain set, flowkooler water pump, Halifax tuned electronic dizzy, rebuilt my original oil pump, stock bottom end, one piece rear main seal.

 

[Oldmanmopar]

If your doing seats and guides get rid of the 3/8 dia. stem valves and install 5/16 dia. valves. One thing to remember you will get as much invested in your 50 year old heads if done correctly, As you would buying a new aluminum set.

 

[dddDuster]

If your doing seats and guides get rid of the 3/8 dia. stem valves and install 5/16 dia. valves. One thing to remember you will get as much invested in your 50 year old heads if done correctly, As you would buying a new aluminum set.

Well except this is a slant and there is no such thing luminineum!

 

[Oldmanmopar]

Well except this is a slant and there is no such thing luminineum!

Well that's the end of that. You will have to pay up for good work. You'll need to make a choice

Good, Fast, or Cheap - Pick two

Fast and Cheap won't be Good
Good and Cheap won't be Fast
Good and Fast won't be Cheap

 

[slantsixdan]

1.70" intake
1.44" exhaust

The primo go-to source for many years (engnbldr) closed down when the guy retired some time back, so I don't know where to send you for 'em now.

Don't veer off into the weeds wasting time and money trying to hunt up nonstock valve stem diameters, etc.

Clean up the ports and pockets a bit; don't go crazy unless you're prepared to hit a water jacket and start all over again with a new head.

Hard exhaust seats are yes. A careful multi-angle grind on all 12 valve seats is a good plan. Bronze valve guides are nice but not mandatory. Umbrella-type valve stem seals are perfectly adequate.

How much to mill the head should be a matter of measurement (combustion chamber volume, compression ratio, etc), not guessing or magic numbers.

 

[volaredon]

Mill the head at least the difference in thickness of old head gasket to new head gasket. New one will always be thicker than the original

 

[ec_co]

For the 1.7/1.44 - are those a Pontiac part or ?