The motor in my truck is a chevy 350 from 1972. What does a 2 piece seal mean and how can I tell wether it is or not. And would you guys suggest, speed-o-motive's 395 stroker kit? My main goal is to build a torque monster up to say 4500-5000 rpm.

 

2-piece seal means just that.... the seal is in 2 pieces, one that fits into the block, and one that fits into the main cap; and the portion of the counterweight for the #7/8 rod journal on the crank flange. The newer 1-piece design has a seal that looks like a wheel bearing seal or something, and a round crank flange, and that last bit of weight on the flywheel.

If you have a 72 block, you have a 2-piece seal. The 1-piece was introduced in 86.

As far as the "kit", that depends on what's in it.... after all, Speed-O-Motive doesn't manufacture cranks or pistons or bearings or rods, they just package up one from column A, 8 from column B, one from column C, and so on, and call it a "kit". Evaluate the parts it's made out of and the price, not Speed-O-Motive themselves.

Putting a 4" crank in a 350 block is not for the faint of heart. I'm afraid that belongs in the "if you have to ask, you shouldn't try it" category. You might want to ask your racing specialized machinist about it (not the corner parts store guy, unless he happens to build the round-track cars in your locale that win consistently), and see what he says.

 

Which by the way, if you install the 2 piece, it goes this way. Take some aviation permatex and lightly cover the rear main seal where it meets the block next to the seal (lightly, I said). The rotate the seal so that it is offset from the rear main seal, So that the seal doesn't match up to the split in the block/main. Now if you have had the crank cut, and the seal is "loose" this space under the seal can be taken up by using a nylon tie-wrap, between the the seal and the main/block (this pushes the seal out towards the crank) trim to fit. The lip faces in.