I am building a 400 SBC I have the block it's a 72 400 SBC with 2 bolt mains. I have bought 400 SBC Mildon billet splayed mains = 79.00. I bought Eagle 6" Forged Rods = 299.99 I bought a New Pete Jackson Timing Gear = 149.99 Crower Cam = 249.99 Wiseco Pistons = 583.44 . Now I need a Crank. Some people are telling me to go with a stock 3.75 stroke. But I want to go high Rpm's this engine is going to go as far as the cam will allow. Cam specs say redline at 6500 is this just a guesstimate on their part or actual redline I was hoping to take her to 7000 if I ever need to. I was going to have the whole bottom end balanced. Some people say that I should destroke it if I want to go high rpms but I don't wanna lose the hp from destroking it. I have to get the Crank before I hit the machine shop. Will I have any problems running a 3.75 (stock stroke) crank up to 6500? It will all be balanced and it will all be forged (pistons, crank, rods) And I will be using splayed 4 bolt mains how well will this combo work? I think I'm doing great for the money I have spent so far.

79.00
299.99
149.99
249.99
583.44 = 1362.41 so far

Crank is probably going to run 400

1362.41
400.00 = 1762.41 sub total

plus around 500.00 in maching costs

1762.41
500.00 = 2262.41 Not bad for a stout Short block right?

But what size crank do you guys think I should run???? Need to know!!!!

 

Build it right (clearancing, balancing, valve springs, etc.), 6500 will be no problem.

 

You kind of already picked your crankshaft out. You stated that you have the pistons for your engine. Those pistons are going to be made to fit with your 6 inch rods and what ever crank the manufacturer decided. Each crank and rod length changes the position of the piston pin within the piston. If your pistons are manufactured for a 350 crank, the piston at TDC should be close to or at 0 deck height. If those same pistons are used with a 400 crank the piston would be sticking out of the block the extra stroke, not good. Also if your pistons are manufactured for 5.7 rods they won't work with your 6 inch So if you don't want to purchase new pistons you are stuck with using the crank that they are made for.
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