Engine ID Quandry

[bwilli2]

Greetings.

I've inherited a '51 5 window. Before it entered our family, someone stuffed a small block V8 in there. A bit of a hack job, but it does run quite well.

The question is I'm having trouble identifying the critter. There is a stamp in the engine ID location on the front of the block but it doesn't align with any of the typical numbers I can find on:

http://www.nastyz28.com/sbchevy/sblock.php
or on
http://www.yearone.com/updatedsingle...gineinfo6.html

It's 5 digit: F7IOD, or F7I0D.

It's still in the truck, and I can't quite get to the casting numbers on the back.

The intake manifold has 37 826 GM 11 cast, and the passenger exhaust manifold has 3747038 RH12 cast, both point to either a 283 or a 327.

If anyone has any info that can narrow it down that'd be helpful.

Eventually I'll be pulling it out and have easy access to all of the various castings and other tells, just trying to get a jump on budget concerns.