i have to ask. What is the critical angle? I've ran a 4.750 stroke and haven't seen any of the "myths" come true upon tear down. And it had hellfire rings in it at that. I honestly don't no where some of these guys come from. The mediocrity boat I guess. It's a lot easier to build something that you have built 100 times before that you know works. But if you never step up and try to make something else work you will never go any faster and stay stuck in the past.

how can you add 1/4 inch stroke and reuse existing pistons without going with a 1/8th shorter rod? do they even make rods in .125 increments? and wouldn't that have more effect on rod ratio than an extra 1/8th of stroke? and doesn't a new set of rods cost more than a new set of pistons? at least rods that will hold up to 800 hp and 7k rpm?

If you add stroke to a block - lets say .25 inch then don't you have to shorten the rods by that same amount or the pistons are going to stick out of the block by .25 inch. Or if there is room you can change the piston with ones that have a .25 inch higher pin height.
If I stroke the engine I will have to change the crank and rods anyways. If I can reuse the pistons what is wrong with that. Why would the rod need to be .125 inch shorter?

Typically , you don't shorten rods with stroke. You go longer . a 4" stroke typically uses a 6.135 rod. 4.25 stroke uses a 6.385 rod. The pistons would need to be changed as well.

Steve,

A stroke increase of .250" is a function of 2 x increase in radius.(.125") BBC rod length increases are related to pin placement.

Bob

How are you going to use a longer crank and Rod with the same piston? With a 4.250 stroke you can use the same Rod but it would have to be externally balanced and I don't think that's a good idea but I still don't see how you could use the same piston...

Ok,first post you wanted to stroke 502 to 540. That is adding 1/4 inch stroke. Later you said you wanted to rebuild using same pistons new rods. I was asking how you were gonna do that. You would need to go .125 shorter or pistons would stick up 1/8th inch out of the holes. As bob said 1/4 stroke is moving rod journal out 1/8 inch. So adding .250 stroke with same pistons would entail special 1/8ths shorter rods which in not a good idea...

What do your heads flow?

You could always jack the compression up and retard the timing . even though you won't make more power, you'll sound cooler telling people at the dock how much compression you have :)

Or just buy the set of Pistons in the swap shop (safe with timing) and look cool beating on the guys running blower motors.