One of the other tricks to assembling an LS-series engine is to ensure that the intersection of the rear cover and the oil pan is properly aligned. On older Gen I small-blocks, the crankshaft protrudes past the bellhousing flange on the block by 0.400 inch. But on the LS-series engines, the crankshaft and the bellhousing flange are in line with each other. The transmission bellhousing on LS engines is also bolted to the back of the oil pan to improve structural rigidity. This means that the oil pan must not protrude rearward past the back of the block or the bellhousing won’t bolt up properly, which can cause all kinds of problems. So the rear engine cover can be installed first, followed by the front cover. Then place four small points of RTV sealer on the corners where the front and rear covers meet the oil pan. Then install the oil pan and make sure the pan does not protrude aft past the rear cover. The plan is to position the pan forward of the cover no more than 0.020 inch from the end of the cover.