LS1 & LS2 Short Block Windage Tray Clearance Guide For 383, 403 & 427 CID Engines Lingenfelter Performance Engineering 1557 Winchester Rd.
Why is clearancing needed?__________________________________________ To obtain the larger displacement of the 383, 403, 427 and any other large displacement configuration, a crankshaft with a 4.00 inch stroke is used. Since this stroke is greater than the stock crankshafts stroke, it is necessary to move items such as the windage tray out so that no interference occurs between the windage tray and the connecting rod bolts.
Step 1: Note: down. This is easiest if the engine is on an engine stand so that it can be flipped upside : Place two 8mm washers onto all ten main cap studs as shown in Figures 1, 2 and 3. This should provide a clearance of 0.125in to 0.140in. This clearancing will cover all GM vehicles. Figure 1: 8mm Washers in place Figure 2: 8mm washers in place on all main cap studs. Figure 3: Windage tray spaced and in place : Install the windage tray and snug the retaining nuts.
Step 2 : This clearancing is required on all GM vehicles. : Install the oil pump pick up onto the engine. You will notice that there is a gap between the windage tray and the backside of the oil pickup. The pickup support needs to be bent so that the backside of the pickup is either touching or nearly touching the windage tray. : The areas you need to bend the pickup support are indicated by black circles as shown in figures 4 and 5.
Step 3 : Since the windage tray has been moved down to make room for the increased stroke of the crankshaft, the oil pan will not sit flush against the engine due to interference between the windage tray and inside ribs on the oil pan. : To allow the oil pan to sit flush against the engine block, the inside ribs and bosses must be ground a minimum of 0.250in using a grinding tool, such as a dremel.
Step 4 : Once the inside ribs of the oil pan have been ground away, check clearance by placing the pan on the engine without any gaskets. Make sure that the oil pan sits flush against the engine block at all mating surfaces. If the pan is sitting flush against the block, there should not be any “rocking” of the oil pan. If the pan does not sit flush, check for additional areas that may need to be ground for clearance.
