Chevrolet Rear Seal Adapters > Products Only STEF’S covers all the combinations required when installing an early design crankshaft in an ’86 and up (late) style block. Unlike other two piece rear seal adapters which force you to also convert to a late pan as well, STEF’S offers both. These billet aluminum adapter kits include all the specialty mounting hardware. Now the obvious advantages of crankshaft selection options and a larger flywheel bolt circle can be utilized regardless of oil pan style or rear main cap design. Part No. Description 7030 SBC Early Crankshaft and Oil Pan with Late Block 7031 SBC Early Crankshaft and Late Oil Pan and Block 7035 BBC Early Crankshaft and Late Oil Pan w/ Gen 5 Block 7036 BBC Early Crankshaft and Late Oil Pan w/ Gen 6 Block