Home page
SPONSOR AD SPONSOR AD

Topic: Easy way to check Gear ration

in Forum: C3 Driveline Components


Easy way to check Gear ration

Posted: 11/20/02 12:57am Message 1 of 6
Profile Pic
Lifetime MemberLifetime Member
Send PM
Ocala, FL - USA
Joined: 9/14/2002
Posts: 72
Vette(s): 1975 coupe, Green, 4speed, T-top, 383 stroked, Hooker side pipes.
Any way to find out what gear ratio car has without tearing it apart ? My 1975 is to have the 3:70 ratio option But not sure. I went to the Drag strip and never got it out of 3rd gear. It has a 4 speed in it. My one friend think's it has different gears. Any help would be really appreciated. Thanks and keep cruzn75.

ACE |headscratch| |sad|


SPONSOR AD:: (Our Sponsors help support C3VR)

Easy way to check Gear ration

Posted: 11/20/02 9:36am Message 2 of 6
Lifetime MemberLifetime Member
Send PM
KETCHIKAN, AK - USA
Joined: 2/7/2002
Posts: 86
Vette(s): 73 custom coupe stingray 4:11 rear,502 cid.
Ace, an easy way to check the ratio is to jack up the rearend, rotate one wheel 1 complete revolution while counting how many times the driveline turns. Example: the driveline turns approximatley 3 and 1/2 turns to 1 turn of the wheel. This would mean you have 3.55 to 1 gears. A little over 4 turns would be 4.11 to 1 and so on....
Hope this helps, Mark


Easy way to check Gear ration

Posted: 11/20/02 11:54pm Message 3 of 6
Profile Pic
Lifetime MemberLifetime Member
Send PM
Ocala, FL - USA
Joined: 9/14/2002
Posts: 72
Vette(s): 1975 coupe, Green, 4speed, T-top, 383 stroked, Hooker side pipes.
Mark,
Thanks a lot ! I will check it out this weekend if possible. I hope mine is a 3:70 like it was optioned as. Thanks again.

Adrian |bouncy| |saluteflag|


Easy way to check Gear ration

Posted: 11/21/02 9:02am Message 4 of 6
Former Member
Send PM
DOWNINGTOWN, PA - USA
Joined: 11/24/2001
Posts: 962
Vette(s): 1969 Monza Red Black Conv / Black Vinal hardtop 454/480 Tremec 5 Speed 308 Posi.Black Leather Interior, PS, PW, Air cond., tilt/tele,AM/FM Cass.-5 Pack CD, Hurst Shifter, side pipes 2004 Yellow convertible with black top and black interior
Don't forge to mark the drive shaft, and the tire so you can more easily count the turns


Easy way to check Gear ration

Posted: 4/5/03 11:06am Message 5 of 6
Former Member
Send PM
NORTH LAS VEGAS, NV - USA
Joined: 3/3/2003
Posts: 90
Vette(s): 1975 Coupe NOM 350: Edelbrock 64cc heads, QJet clone, Performer manifold & cam, gear drive and water pump; MSD ProBillet dist and 6A box, Comp rollers, Hedman headers into true duals, Magnaflow cans,TH400 w/shift kit, TT2's, 3.70RA, hi-rise hood
All the formulas are in the Pit Stop Q&A in the May 03 HOT ROD.

You can compute RA ratio if you've clocked MPH at RPM, e.g. 72 MPH at 3500 RPM, and you know your tire diameter and trans output ratio (1:1 if no OD).

RA Ratio =
(rpm X tire diameter) / (MPH X trans output ratio X 336)

|saluteflag|


Easy way to check Gear ration

Posted: 4/15/03 11:56pm Message 6 of 6
Former Member
Send PM
Marietta, OH - USA
Joined: 12/7/2002
Posts: 2
Vette(s): 1972 Coupe L48 Automatic Classic White/Saddle Leather 1986 Coupe L98 Automatic Dark Red Metallic/Graphite Leather
Hi Ace I have a restoration book that tells how to decipher all C3 rear ends, including gear ratio and date of manufacture. The codes are stamped into the bottom of the rear end. For example on my 1972 small block coupe the codes are LR W105 E1. Translated it means LR = 3.36 gear ratio W = Warren, Michigan plant 105 = April 14 (Julian calendar - the 105th day in the year 1972) E = Eaton positraction unit and know one seems to know what the 1 after the E means. If you send me your codes I will look them up for you. E-mail me at mpd4754@charter.net. Thanks, Mike


in Forum: C3 Driveline Components


SPONSOR AD: (Our Sponsors help support C3VR)