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Author Topic:   Rear Gears and RPM
smayo964
Member
posted September 19, 2001 10:52 AM
I'm in the process of moving into the modified ranks from street stock and in the process of building a new chassis. One area of confusion is the rear gear for these cars. What is a normal gear ratio range for an approx. 3/8 mile, high bank, fast track? What engine RPM ranges should I expect? Thanx for the help.


CNC DOC
Member
posted September 19, 2001 06:37 PM
Thanx CNC DOC for the info. Is the gear ratio shown the final ratio (trans x rear gear), or just the rear gear. I was running approx. total ratio of 6.90 in the street car and turned 6,700. If those are total ratios given (5.14/5.29), are they that low to keep wheel spin under control? Just trying to get a better understanding of the setup.


FS93
Member
posted September 20, 2001 05:49 PM
He is listing the final gear ratio. We either run a 5.29 or a 5.43 and turn 7-7200. Most modified drivers dont do a lot of running in second gear or anything like the street stockers do. In my old factory stock on a 1/**i track we ran in second gear(saginaw 3 spd) for a final drive of 6.52(1.75x3.73). The mod we run a 5.83 rear gear and run it in third which is a 1:1 ratio. The reason for the big difference in gears is the most street stocks run larger tires, adn need more gear to pull them to the same RPM. Hope this helps.


CNC DOC
Member
posted September 20, 2001 07:20 PM
At I-55 Raceway in Pevely,Mo. which is a high banked 3/8 track, most of the mods running roller cam, high compression engines are running 5:14s. 5:29s on the flat tappet engines. If the the track stay's tacky I would go with the 5:29.


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