Thread: pistons

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Originally Posted by realitycheck

There is a possibility I may have found a 400 Chevy crankshaft....

Would I be crazy if I started thinking stroker?

Nope, not crazy at all. BUT and a big BUT, That cast 400 chevy crank is old and used, and maybe all used up. Firstly, the 400 crank is externally balanced and is balanced for the shorter 400 rods. The 400 rod is lighter because it is shorter, the only problem is this the shorter rods have a higher side thrust as the piston moves up and down the bore. This increases bore wear. This was noted when the 400 blocks had to have a rebuild at earlier intervals than any other chevy motor. So you have a crank that is over 20 years old, it is cast iron, and it needs to be machined, if you want to run the longer chevy rod 5.7 inches in length, it has to be rebalanced. All this cost is going to stack up in a hurry.

Here is the easy and slightly more expensive way with new gear. It is proven because this is what I have done. Get an Eagle crank kit. This contains an eagle cast steel crank that is radiused on all the journals and oil holes it is already balanced for the 5.7 inch eagle rods you get with the kit it is internally balanced so you dont get any crank flex, it is stronger and brand new. My kit cost me here in New Zealand 1199.00 NZD. For this I got new hyperutectic pistons, new rods, new crank, gasket set, rings, main rod and cam bearings. Remember our dollr is worth US .62 cents plus freight and taxes on top of that. So you should be able to do a lot better. 2 things you should do with this kit, polish the bearings and get the crank and everything that attaches to it balanced. The 383 is a great street motor you dont have to rev it to make power on the street it has heaps of low down torque.

Other issues ? you have to clearance the block and check for cam lobe and rod interferance. but you can do this by setting up the crank in the block and grinding with a dye grinder with a carbide cutting tool. Camshaft: my preference on this baby is crane powermax solid lifter f-278-2, I am sticking a blower on top of all this, and am running 8.5 / 1 compression, But crane states that naturally aspirated you are advised to run 10.5 11 / 1 static compression ratio. To be absolutely sure give crane cams or you favourite cam grinder a ring to work out exactly what you want.

Hope all this explains some . S