I was looking at sbc cranks on ebay today, and found a 4.100" stroke one with the smaller 350 journals. With my calculations, it should produce a displacement of just shy of 412 ci with no overbore.

My question is, has anyone heard of a setup with a this type of crank? It seems to good to be true, and I bet finding pistons would be almost impossible, but if anyone has any input that would be greatly appreciated, as it sounds pretty damn cool.

Oh, I also see that 3.875" (396 ci) cranks are also quite popular. If anyone knows about these bigger inch cranks and what it takes to install them, I would greatly appreciate it.

 

Yeah but will it fit. I dont know what the max stroke is for a stock block Im thinking 3.75. Im pretty sure you would need an aftermarket cast block to get those large strokes to work. Maybe someone will know more.

 

You might be able to clearance a stock 350 block enough to get it to fit but im not 100% sure, ill leave it up to the big cube small block guys to confirm.

 

Could you find a piston with a wrist pin that high?

 

Wouldnt cam to rod clearance be a major factor?

 

Clearance of any kind would be a major factor. That kind of stroke would be best left to an aftermarket tall-deck block with increased cam to crank centerline distance.

 

I don’t know all that much about this subject but I know that people in the past have had problems with clearance between the rods and the cam with a 383 build. I mean wouldn’t the crank of a stroke of 4.01 have less space between rod and cam than a crank of a stroke of 3.75? Once again I do not know if this is correct and I could be wrong and if I am can someone please correct me.

 

A crank with a stroke that large will have less clearance everywhere. No one spot is any more or less critical than anywhere else.

 

I'm impressed by the number of replies in such a short period of time, I like this board.

I called a machine shop earlier today and the guy working there said that the newer stroker cranks have been revised and clearance issues are no longer a problem. This is kind of hard for me to believe, but then again I don't own a machine shop.

Again, if anyone can verify whether it is reasonable to fit a crank with a stroke longer then 3.75" it would be greatly appreciated.

 

I don't see how clearence issues can suddenly not be a problem.It's still a big stroke in a block that was never intended for more than a 3.48" stroke.
The question I have to ask you,is why would you spend that kinda dough on a crank,rods,custom pistons,etc.,and still be strapped with a 4" bore?If you were to do this,you'd need an aftermarket block with the raised cam journals,period.
I had a 421 in my car about 3 years ago,(3.85 stroke)and It was a clearance nightmare.I can't possibly imagine squeezing any more stroke into a stock smallblock.So if you've gotta go with an aftermarket block,why not go great big?You could build around 440 cubes out of a Dart or World block with a 4.10 stroke,maybe even a bit bigger.