Whoever rebuilt the engine in my car put different heads on it...I think, they are sprayed a different shade of blue. How do I identify them and how do I figure out what the compression ratio is of my engine???
Its a 400 by the way.
Thanks
Mitch

Whoever rebuilt the engine in my car put different heads on it...I think, they are sprayed a different shade of blue. How do I identify them and how do I figure out what the compression ratio is of my engine???
Its a 400 by the way.
Thanks
Mitch

Take a look at the code on the center exhaust ports and let us know what it is. Stock would be a 670 code.

670 is on the head, what compression ratio am I looking at?

I think I know this one....it's 13.75 to 1 isn't it?

could be 10:75to1

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by dogboy:
could be 10:75to1 <HR></BLOCKQUOTE>

YOU WIN!! (if all is stock)

The factory was always a little optomistic on their compression ratio estimates. They did state 10.75:1, but if you plug in the actual numbers you end up at something closer to 10.28:1. The good news is those are the correct heads for your goat. The bad news is anything over about 9.5:1 with todays gas is probably going to ping. Just keep your ears open for pre-ignition.

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by urhere2:
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by dogboy:
could be 10:75to1 <HR></BLOCKQUOTE>

YOU WIN!! (if all is stock) <HR></BLOCKQUOTE>

Doh! That's right...I knew it was a .75 in there somewhere! Been a long time (12 years) since I've been in this game, I finally got a old Pontiac last week so I'm back in it!! Yeeehaaaaaaa!

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