Good morning everyone. I bought a 455 that I'm going to start rebuilding. I also have a 425 block and B heads of that block. The 455 has G-heads. I'm going to see which block and which heads are the best for reconstruction.

 

The 455 is a 1971 motor. The blocks are equivalent, except that the 425 may have the oddball 45 deg lifter bank angle and/or the 0.921 lifters. Cams and lifters can be more difficult to find and more expensive when you do. 425 has a forged crank, but obviously a shorter stroke, The pistons, rods, and crank must stay together, but either set can be used in either block. The 1971 heads have the factory induction hardened seats, but the first time you do a valve job that thin hardened layer is removed. Otherwise the heads are equivalent, except that the G heads will have used valve rotators and thus have deep spring pockets in those locations. This is not a big deal, but if you delete the rotators you need to shim under the springs to make up the thickness difference. Either set of heads could have come with big or small valves.

 

They have lost the crank rear cap and a connecting rod cap. Where can I buy those pieces?
Are those pistons std?

 

Jaun,
Those pieces are matched to the block and connecting rod during the manufacturing process and are very difficult to replace. The rod is not a problem, just buy another rod but the block will be a big issue. Even if you can find a used cap it is almost impossible to find one that will be able to be matched to the block . It will definitely have to be align bored.

Dont take this the wrong way but to be honest with you if a customer brought me a block and crankshaft that were that rusty I woul point them to the scrap metal pile. The crankshaft might be savable by regrinding but i doubt that the block is worth even trying.