The ones with the thicker casting are 200 blocks, oddly enough you're talking complete rubbish.
The pinto or T88 to give it it's correct name was codenamed YAA and was 100% PURE pinto, but don't listen to me read read Mario Illien's comments, which went on to state
" comapred with the T88/pinto engine from which the new turbocharged YB evolved almost everything was changed, except fro the cylinder block, front cover and jackshaft, except for these parts all was new.
For those that don't know Mario was the man behind the engineering of the YB, I've a suspicion he knew what was used as he used it and asked for it.
tabetha