Over the life of their production, did 400's come with more than one piston dish size? And what cc was it/they?

EDIT: Alright, I think I ought to just get to the point here, to help you help me.
If I get a bone-yard 400, and put 64cc heads on it, what compression ratio will I end up with, with what head gasket? Is that enough info to come up w/an answer?

-Tom

 

You could work it backwards. Find out what compression the engine in question came with stock, find out the chamber size the stock heads had, then estimate the compression with the smaller heads.

 

I could....if I knew what the stock comp ratio was.

There are two sbc 400's down in SLC at Pick n Pull. $140 for the long block. I want to compression test them and take the better one. But I need to know what the compression would be with 64 cc heads.

Goood thought though Apeiron. Thanks for the input.

 

All of them that I've worked with were around 15-16cc. But I don't recall ever having a known original short block from 70 or 71, so I don't know if those were the same or not.

Having done that more than once, I can tell you that you'll most likely end up somewhere in the mid to high 9s, like 9.5 - 9.7:1, depending on your head gasket and so forth.

 

Thanks RB, that's exactly what I needed. One engine is a '74, and the other is a '76.

One last thing; do you know the compression height of the stock assembly? Should I know that already?

We'll see how they compression test...

You know where I'm going w/this don't you?

 

Stock compression height is in the .025" - .030" range, usually. Could be more, could be less, that's a fair guess though.

Stock CR should be in the mid-high 8s. They'll have a 929 cam, should do around 180-185 psi if they're in good shape.

 

Thanks RB. That is excellent information will be a significant help for this little project. Much appreciated.

-Tom