Gear ratio

[juni]

Our track is gonna switching to imca hobby rules we run a 700 gear with 383/377 12 5 motors with 23570/15 tires we will be going 360 9to1 20570/15 tires what gear 1/4 mile dirt track and a 3/8 track

[Brian Wise]

d**n!, with a flat 700 gear what were you turning for RPM's? I don't have an exact answer for you. But I know that most of our IMCA Hobbie guys run a 5:67 or 5:83 on the half miles real close. I'll ask around and get back to you ASAP, but my first impression would be that on the 1/4 mile they'd run a flat 6, or 620. Remember it also depends on your banking, and how much speed you are able to carry in cornering. I'll find out and let you know! Oh, and Juni, Don't be a stranger!!!

Thanks, Brian

[juni]

We ran a tach several years ago and turned around 5800 to 6000 rpm's . O tach broke so we just don't use one anymore . Driver says seems okay . When i first built him a car 8 years ago he was a rookie and tried a 620 gear he was fast down the straight away but could not get off the corner so i added more gear and he got faster i think i could add a little more gear and still been okay but the price of the gears was around 230.00 and couldn't bring my self to spend more money . What kind of motor do most imca hobby guys build in your area ? I have a machine shop sponcer so we can build what we want I am looking at 355 with 6.125 inch rods and 3.48 stroke all lite weight parts and 441 heads 313 intake . Any input would be great thanks.

[Brian Wise]

It's hard to beat a 355. As long as the stroke is 3.48 you should be able to get by with the long rods. And for sure you want the lightest stuff out there. 441's are durn good heads, and the 993 is it's late model cousin. Just keep in mind, you can hide lots of goodies inside the motor and IMCA or the competition will be none the wiser. (as long as it stays INSIDE!!!)

Brian