I did a search and didn't find any discussion on this topic, soo here it goes. Im very rusty on my rod ratio theory so forgive me if Im off. For discussion purposes .030 overbore and stock stroke. Most factory rod ratios are very kind to the pistons/cyl walls. So by adding a chevy 6.635 or 6.800 length rod the ratio is going to change. Now because of the longer rod, and I would think it would raise the ratio and cause excess bore and piston wear. But what is accectable/unaccectable on a street/strip car??? Michael :Brow:
rod ratio doesn't have anything to do with the bore, the number is derived by ratio = rod length / stroke length. longer rods produce LESS rocking and wear. http://victorylibrary.com/mopar/rod-tech-c.htm
Here's a chart I did in Excel. The numbers on the left side of the chart are the rod lengths, the numbers at the bottom are the stroke. The left most number in each cell is the rod angle in degrees, and the right most number is the rod/stroke ratio. The "pink" cell is the stock buick 455 numbers. I know someone who runs a BBC top sportsman car with a rod/stroke ratio of 1.50 and a rod angle of 19.44. That should be terrible (and may be!) but he keeps it under 8000 rpm, has little wear on the parts, and goes rounds.
