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Discussion Starter #1
Well, I just finished rebuilding my 72 pontiac 400 to stock, which will eventually go in my 69 GTO. Now I have the opportunity to buy some # 62 heads for $300.

I know that I will have to take them to a machine shop and have harden seats installed in order to run pump gas along with some other things.

What all will the machine shop have to do to the heads and what can I expect them to charge me?

Also, what would I have to do to my stock 400 in order for it to accept these # 62 heads?

Thanks for any help you can offer,
Mike
 

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You'll find (at least) two opinions on whether hardened seats are actually needed. One says "always", another says "only if the engine sees sustained high load, like trailer towing." I tend to be in the latter camp but don't have cold hard proof one way or the other. I know Jim Lehart tends to say the same thing, and personally I trust him on that.

As far as other work goes, with 62's and those 72 cc (nominal - measure them) you'll need to run dished pistons to get compression down in a range where it'll be comfy on 93 octane especially with a mild/stock cam. Compression ratio is another topic that tends to generate passionate and varying opinions. Can you push the limit successfully? Some people do and get away with it - but you have to really know what you're doing. For me, when I 'ran the numbers' on my engine (461) the difference between 9.5:1 and 10:1 was only about 8 hp, so I decided it wasn't worth the risk.

Bear
 

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For your stock 400, you will need dished pistons to perform well on today's pump gas. As for the cost of a valve job, I've spent as little as $400 and as much as $1400. It all depends on the condition of the heads and how much work they'll need. Hardened seats is your call. I've been running regular seats in my GTO's for decades without issue, but I'm not pulling a boat and I'm not running down the road at a sustained high rpm, either.
 

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Discussion Starter #4
#62 Heads

Yeh that's what I figured. It all comes down to money and that's just something I don't have a lot of right now. I guess I'll just stick to my 250 hp and be happy with that.

Thanks for your inputs,
Mike
 
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