I just purchased a set of 840 cast heads with a date code of A-22-9 3919840 cast# heads. I just measured the valves and they measured 2.18 intake and 1.72 exhaust. how hard is it to change them to 2.20/1.88 and is it worth doing?
It's for a L-72 427 69 4-bolt staying with stock pistons but just ordered a UD HAROLD .586/.586 mechanical cam for it, with springs, but every thing else is stock.
Thanks for the help.

Not hard at all.

BUT you need to have a shop that has done it before do it so that it doesn't get messed up.

You may consider leaving the intake alone and installing just a 1.88" or a 1.90" or if thought there is enough room, a 1.94" exhaust valve!!!

This WILL help power b/c it helps pumping losses... IMHO. pdq67

<BLOCKQUOTE>quote:</font><HR>Originally posted by pdq67:
Not hard at all.

BUT you need to have a shop that has done it before do it so that it doesn't get messed up.

You may consider leaving the intake alone and installing just a 1.88" or a 1.90" or if thought there is enough room, a 1.94" exhaust valve!!!

This WILL help power b/c it helps pumping losses... IMHO. pdq67<HR></BLOCKQUOTE>to the best of my knowledge you would also have to have biigger seats put in the heads

anyone else? should they be flowed, ported, polished, or is this just a waste of money?

I've heard of heads that have a big enough seat to grind down, but I had mine replaced when I upped the valve size anyways, and got the bronze seats. Also, a little unshrouding in the exhaust area does no harm at all - probably not a bad idea. And a pocket port if you have the $$$. But no need for a full port or polish, and certainly not flow-bench.

I also agree with the above - the intake valve size is just fine, and increasing the exhaust alone is a very good idea.