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Thread: Trying to get gear ratio
01-24-2011, 06:43 AM #11
- Join Date
- Sep 2010
- Far West, Oregon USA,
- Blog Entries
At 3,000 RPMs @ 55 mph with 29 1/2 inch diameter tires that would compute to 4:75 gears, but I doubt your tires are that short. Go measure the dia of one of them & post back here with exact RPMs @ 60 mph & with your tire dia & I can give you a more exact ratio..1988 Chevy C-3500 2wd (no pic)
350 c.i. 5.7 L Stock Block, 4 Bolt Mains
L-31 Vortec Heads, Edelbrock Cam & Intake,
Holley 650, Flowtech Headers, Magnaflow exh.
Jet Trans 700R4, B&M Ratchet, 4:10 gears,
3" susp. lift kit "shadetree"
No rev limiter, No speed limiter lol
01-24-2011, 03:09 PM #12
- Join Date
- Dec 2010
- 25 Mi. E. of Kingman, AZ.
I found some RPO codes that might help. GK9=4.63, GS6=4.56, HF8=4.83. I don't know if these were all available in pickups. My 1990 C2500 was built as a camper special and came with a 4.10 & a TH400 3 speed. Also if you check your speedo accuracy with a GPS or a measured mile and it's correct the truck probably came with those gears. It's a pretty good project to recalibrate those early electronic speedos.
Good luck with your project.
Last edited by Taddpole; 01-24-2011 at 03:21 PM.
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