hey guys. im lookin at doin a very solid 460 build, and i want to know if a factory block will hold a 4.5 inch bore and stroke. my research tells me that a block from 79 will handle the stroke without pullin the pistons out of the cylinders, but will it take the bore? final displacement will be 573, and it should be able to run on 87 pump gas. thanks.

 

there are a few guys out there running 4.5 stroke in a production block but if you are going to go 573ci better look to an aftermarket block. you can run a 6.8 rod with the 4.5crank instead of a 6.7 rod and it will help keep the piston in the hole.

 

how bout the bore? is it too much?

 

very few factory blocks are good for .140 overbore. Even at .080 over bore you need to have it sonic tested and you will almost always find atleast one cylinder that will be slightly thin but can be used.

you coudl sonic test your block and then sleeve a cylinder to 2 and do that but personally I would get an aftermarket block. Better oiling, and 4 bolt mains is worth it.

 

so, ya think i could go .040 over and make it a 4.40x4.50 stroker without needin the sonic test?

 

sure the only problem with .040 over is those are usually not shelf pistons. .030 over is shelf pistons as well as .080. I know several guys that bore .080 without sonic testing but personally it's worth the money instead of spending the money machining a block and then find out it is thin.

 

Isn't 550 c.i. about the max for a factory block ?

 

im not worried about the pistons. they will be custom pieces, specific to the motor and the head.

 

557 is the accepted norm. With custom cranks etc you can get more of coarse. such as using a 4.6" stroke with an .080 over (4.440) you end up at 570cid.

and a got portion of the blocks CAN go to 4.5 bore if you sleeve 1 or 2 cylinders that are thin.