DynoSim combinations

6.0 rods get up into the oil ring land and I do not advise more complexity and more things to go wrong than you need in an engine build like this, particularly for a beginner. With nominal +/- 66cc heads (production heads usually pour larger than published data), these pistons, with a 22cc D-cup will produce 9.6:1 static compression ratio. An added benefit is the tall 1.433" compression height, meaning less block deck to cut off to reach a target squish of 0.035" to 0.045".

6.0 rods get up into the oil ring land and I do not advise more complexity and more things to go wrong than you need in an engine build like this, particularly for a beginner. With nominal +/- 66cc heads (production heads usually pour larger than published data), these pistons, with a 22cc D-cup will produce 9.6:1 static compression ratio. An added benefit is the tall 1.433" compression height, meaning less block deck to cut off to reach a target squish of 0.035" to 0.045".

Machining operations to the block, besides the boring and honing to +0.030 oversize, will include align honing the main bearing bores and cutting the block decks to square and to the proper block deck height to work with the piston deck height and gasket thickness to set the squish. Stock block deck height is +/- 9.025". The height of your stack of parts will be 1.875" for the crank throw radius, 5.700" for the connecting rod center to center and 1.433" for the piston compression height, for a total of 9.008". If we use a gasket thickness of 0.039"/0.040", then we will have to cut the block decks 0.017" to reach a zero deck. This will put the squish at 0.039" or 0.040", depending on the head gasket used. Decking the block will also insure that the block decks on all four corners of the block are the same distance from the main bearing centerline, meaning that static compression ratio will be closer to equal across all cylinders and will also contribute to the heads and intake manifold lining up and sealing the way they're supposed to. Thinner shim head gaskets used to be available for the 400, but not any longer. Some fellows have used 350 shims and drilled them for steam holes, but the bore of the gasket is iffy with the larger 400 bore. If you get any of that thin shim out into the cylinder/chamber at all and it glows hot, it could be a potential trouble spot for pre-ignition/detonation. Better to use a composition gasket that is engineered for the purpose and cut the decks accordingly. Speaking of steam holes, the heads will have to be drilled for them. Here's the tutorial....

Machining operations to the block, besides the boring and honing to +0.030 oversize, will include align honing the main bearing bores and cutting the block decks to square and to the proper block deck height to work with the piston deck height and gasket thickness to set the squish. Stock block deck height is +/- 9.025". The height of your stack of parts will be 1.875" for the crank throw radius, 5.700" for the connecting rod center to center and 1.433" for the piston compression height, for a total of 9.008". If we use a gasket thickness of 0.039"/0.040", then we will have to cut the block decks 0.017" to reach a zero deck. This will put the squish at 0.039" or 0.040", depending on the head gasket used. Decking the block will also insure that the block decks on all four corners of the block are the same distance from the main bearing centerline, meaning that static compression ratio will be closer to equal across all cylinders and will also contribute to the heads and intake manifold lining up and sealing the way they're supposed to. Thinner shim head gaskets used to be available for the 400, but not any longer. Some fellows have used 350 shims and drilled them for steam holes, but the bore of the gasket is iffy with the larger 400 bore. If you get any of that thin shim out into the cylinder/chamber at all and it glows hot, it could be a potential trouble spot for pre-ignition/detonation. Better to use a composition gasket that is engineered for the purpose and cut the decks accordingly. Speaking of steam holes, the heads will have to be drilled for them. Here's the tutorial....