Ideal Drag Race Bore and Stroke

You totally missed my point.

I’ll add this because it matters. This is just one point.

If rod length doesn’t matter, why not use a 6 inch rod? It’s cheaper. Bearings are easier to find. And it doesn’t matter right?

Or why not a 5.7 rod? Again, it’s a Chevy length so they are easy to find and bearings are everywhere.

The reason it’s not done is because rod length does matter.

The shorter the rod, the heavier the piston. The shorter the rod, the lower the pin height and the piston has more rock around TDC and it hurts ring seal.

Rod length changes cam timing as well.

So when you boil it all down you find in the end that what Smokey Yunick said 50 years ago was and is right as rain.

Use the longest rod you can fit. And EVERYONE does it, but they slam the guy and say he didn’t know what he was talking about blah blah blah.

Of course, with Chrysler junk you can get the rod too long because the deck heights are too high for the stoke length they use. But that’s the exception and not the rule.

Not one single engine builder I know uses a rod shorter the longest they can fit. To the point they run the oil ring around the wrist pin.

That should prove to you that rod length matters otherwise you’d never see a piston that has the oil ring around the wrist pin.

Physics didn’t change. Smokey wasn’t wrong. Rules changed. And shoe polish won the day.
Mr Turk, I'm not trying to argue with anyone. I was always taught that the closer that you could get to 1.9 rod to stroke ratio the better. And I wanted to use a 6.250 or 6.300 rod. We used a 6.125. And bought a nice set of pistons. The engine made 841hp at almost 7500 rpm. It turned out well. It made 80 hp more that I thought it would. So end the end he told me not to worry about it and it worked out better than I thought is would. Maybe I mis-stated. Maybe I should have said it doesn't make much difference instead of it makes no difference.