<html><head><meta http-equiv="Content-Type" content="text/html charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class="">I pulled apart a spare short block to get at the crank, and thought I might get the block cleaned and prepped at the same time. However, the block is different from any of the GT6 blocks I’ve used before. Serial # shows as a GT6 motor - KD759681 - but the bores have notches cut out in the sump end and the block has cast-in “bulges” on the side opposite the distributor/oil galleys.<div class="">I’m guessing that this is a block that could have been used either for a GT6 or TR6 and the clearance is for the added TR6 stroke - but would like to confirm that they are interchangeable. Definitely has a GT6 crank in it - same stroke. Other aspects of the castings look the same. Having been through probably 3 blocks in the past ten years, I’m puzzled I haven’t run into one of these before. </div><div class=""><br class=""></div><div class="">Photos of current and different block attached. The clean one is my current GT6 block - there’s no serial # on that - got decked off.</div><div class=""><br class=""></div><div class="">Anyone know?</div><div><br class=""><div class=""><img name="IMG_0930.JPG" class="" apple-inline="yes" id="8FB7EFA7-829B-4BDB-B00D-6DAC39AB4EDA" src="cid:05FF0AE5-9E0E-41AF-A59C-9713481CD4AA@fios-router.home"></div><div class=""><div class=""><br class=""><br class=""><img name="IMG_0929.JPG" class="" apple-inline="yes" id="262BB849-B65F-461E-BE75-5D07AD3DD917" src="cid:C2FEC05F-4336-4415-B135-6A30F1497802@fios-router.home"><br class=""><br class=""><br class=""><br class=""><br class=""><br class=""><img name="IMG_0927.JPG" class="" apple-inline="yes" id="1ED0F848-2C0C-466C-8A2C-B652FCDB528B" src="cid:5AA0F9A2-B2E3-475D-BE9A-CE06AF33B12F@fios-router.home"><br class=""><br class=""><br class=""><img name="IMG_0926.JPG" class="" apple-inline="yes" id="088C9C45-AEA1-49B4-933B-E4B57C276A41" src="cid:3C39566F-F07D-433D-B6D4-7A0B39E6AD40@fios-router.home"><br class=""><br class="">Sent from my iPhone</div></div></div><br class=""></body></html>