What should I do to them, and what should I not have done to them.....??? They have been sitting next to a doner 455 for 20 years, springs are rusty...engine guy mentioned new springs, new seals, hardened exhaust seats, a 3 angle grind, CC it and mill the face to make sure it is flat.... This is going to be a driver, and being brought back "closer" to original

 

New guides, and positive wiping seals.
Factory umbrella "seals" do not seal, just shield.
Easy to lose 20 hp from bad/loose guides.
Jim

 

Do not cut them excessively,or do any porting.Those heads are worth more the more original they are,but you do need to rebuild them.valve job,guides,minimum milling to make flat,new valves,seals,springs,locks,retainers.If the seats are fine,leave them.If they got pitted from the rust,replace all of them.If you grind too much away from them,you will end up with a bunch of different installed heights for your valves/springs.

 

What are the differences between the "F" heads and the "G" heads? I know that in '71 they went to low compression engines, didn't know if that had anything to do w/ the heads and I know that the "G" heads I have are the small valve model (atleast I think they are, from a '71 Olds 98). I saw that you said this guy shouldn't do alot to the "F" heads as they're OK just the way they are. Thanks in advance f/ the input.

 

A few thousand dollars. The F heads are rare, and that is the reasoning for keeping them close to stock.
G heads are a dime a dozen, do what you want with them.
I don't think an F casting will do much better, performance wise than a G.

 

If the "F" and "G" are so very close performance-wise, then why the big money difference and why are the "Fs" so sought after? Surely it's not just the big valves. What are the physical differences that make the "F" such a great head?

 

I thought the F heads had bigger valves and stronger springs for the W-30. I have read some of the differences listed elsewhere. I have G-heads on now and want to get back to the more stock/original looking

 

The F-heads only came on 70 W30's,so the production number is much lower than C's,E's,G's,etc. They are more of a restoration part,and the resto crowd likes them as original as possible.You have such a car,so I would put them back on.I just wouldn't get crazy with them. If you want to do a fulley ported set of iron heads,AND want the look,do a pair of E's,and grind the bottom leg off.There are a pair of those up your way in Michigan,that I owned.They'd be perfect.
Yes,I have real F's on my 72,and they are fully ported,but I would not have done this if they were bone stock in the first place. I bought them in 2001,and they had a history from being on a stock eliminator race car.They were not ported,as you could not do that in that class,but they were milled all over the place,making them unsuitable for a restoration engine.The exhaust flange was milled until the center divider was flush,and you could not run factory exhaust manifolds with these because the manifolds will hit the block.I wanted a set that I could port,and these were it.I also want to put them on my 70 W30 in the future,and park the original engine,leaving it original.
As far as performance goes,you will get the same amount out of any factory iron head,except the J's. just another note: Gasket matching will do about nothing since the rest of the port gets smaller inside. The large intake valve is good,and you can put that into any head,if it doesn't have it already.As for the exhaust,leave it the size it is.The 1.68's are fine.The 1.71's won't do anything.The exhaust will get out.If anything,keep the smaller exhaust valve & go even bigger on the intake,like 2.11 or 2.19,if your heads are really worked.Sorry,I'm getting off on another tangent.