I was under the impression I had a complete jdm B18C-R, the head is an itr head I've confirmed that the cams are ITR cams, the pistons are marked P73 and have a nice high "dome". But I went to remove the oil pan and on the block it says "p72" aka a GSR, I have the oil pan off and at this point am about to rip the pistons out and rebuild it. But before I do that are there any was to tell if it is in fact an R block, I'm new to engine internals but am familiar with the terms. Its not the fact that it's possibly a "gsr" w/P73 pistons it's the fact it was sold to me as such the block stamp on the front reads "B18C".

here's a pic of the "p72" and again on the section where the t-bracket mounts and on the oil pan, other then that p73 for the rest/ITR cams.




This stamp location is right by the flywheel cover that bolts to the block/over the oil pan

 

B18C-R block is stamped p72 too. Why? Because they are the same as jdm gsr. The internals are what make it an "R" block. If the crankshaft and pistons are correct then you got exactly what you were told.

 

All B18C's and B16B's are housed in P72 blocks/pans. The change in internals determines which short block you have. That, combined with the head will determine which long block you have.

 

oh ok, thanks guys wasn't sure figured p72 was instant "gsr" lol.

 

What they said, plus the serial stamp under the engine code on the block will tell you.