The '53 powerglide engine did have the two bolt valve cover. It also has the "captains bars" on the block just above the starter, as does the '54 powerglide.
Should still have the number stamped by the the distributer, however, unless it was a replacement block from the factory.
Finally, it is easy to convert a head to a two bolt cover by installing two longer studs for two of the rocker arm bolts. You can tell by removing the cover and looking to see if there are tapped holes for the four bolt cover.
P.S. I have a '53 235 powerglide head on the shelf, and the casting number is 3701887 - same as yours.
Kurt
Last edited by Kurt_51carryall; 05/03/2012 3:37 PM. Reason: Added head casting number
