If you take a dial indicator and measure the main cap inside diameter, installed, on a small block 400, what do you expect to read?

I mean the block, not the crank. I know the crank should be 2.65.

I'm getting 2.84, I think. Is that correct?

Thanks!

I am asking because apparently there are two different rear main seals for a 400, depending if its been align honed?

http://www.camaros.net/cgi-bin/forum/ultimatebb.cgi/topic/4/5050.html?

So... does that mean I have to specifiy this when ordering main bearings?

I don't know if this blocks been honed but by my measurement, it kinda looks like the larger size.

Comments and help welcome.

Thanks in advance!

Rouge,
The bearings are the same either way. The only difference is the seal. When a 400 block is align honed you have to cut down the "lip" that the rear main seal sits on. Doing that requires using a special rear main seal ( Fel-Pr 2909). There is no difference in the bearing itself.
Hope this helps,