Gears

Duster2022! said

I have a 72 dodge demon that I’m running a 440 big block. Motor was dynode at about 537 horse at 6000 RPMs. I am trying to figure out what gears I should use in my 8 3/4 rear end. This is strictly just going to be a street car. Not sure if I’m going to ever drive it long distances on the highway but maybe occasionally I will. I’m looking some advice on what would be a good rear end gear I want some thing that is quick from white to light so that I don’t get eaten up by all these imports, but I also want something that I can possibly drive to car cruise ins that are out a little bit of a distance.

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Problem is there's no right answer, for 1/4 or 1/8 mile you'd gear it so hit around peak power at the finish line probably 3.91-4.56, on the street it's vague goal, traction and drivability become a factor, it's really a personal choice. Your engines top end powerband 90% of it's power is probably 5500-6500 rpm you want your gearing to get there at reasonable street speeds or you'll rarely get into your power band. Your probably gonna want to do full throttle runs up 80-100 mph max around the streets so I gear it to hit 100 mph at 6000 rpm in second if you want to run a deeper gear, gear third for 1/4 or 1/8 mile even if you never go.

3.55 @ 6000 rpm peak hp
1st 57 mph
2nd 97 mph
3rd 141 mph

3.55 @ 4500 rpm peak ish tq
1st 43 mph
2nd 73 mph
3rd 106 mph