What gear ratio would you recommend for me?

Discussion in 'Got gears?' started by mjoe7, Jun 7, 2005.

  1. mjoe7

    mjoe7 In the beginning God...

    What would you guy's recommend for rear gear ratio with my following engine combination? I drive 90% street. Race on occasion. I was thinking 3:23's?

    BBB/455, bored .030, 9.5:1 compression, ported heads and other work not sure what else, Big headers with 3" Torque Tech Exhaust System.
    Edelbrock Performer Intake with 1" open spacer, K&N Air Filter,
    870 Holley Street Avenger carb.
    HEI custom curved to 24*@3,000 rpm from Davis Unified Ignitions and "Live Wires" plug wires. NGK plugs with .055 gap.
    TA 288-96H cam
    12 bolt Chevy rear from 71 Monte Carlo with 4:10 I think? 3,000rpm @60mph.
    TH350 with ATI 2800 stall, shift kit, and so on...
    I hope to be in the 12's in the 1/4 mile.
    I actually think the low gears are hurting me. It shifts out of 1st way to quick and it accelerates in 2nd the most.
    What do you think?
    Thank you;
    Mike
     
  2. 70 gsconvt

    70 gsconvt Silver Level contributor

    You could easily use 3.55's and still be under 3,000 rpm's at 70 mph on the highway. I have 3.73's and was spinning about 3200 rpm's at 70 mph. I now have a 200-4R in the car. Haven't had it out yet though for the formal "testing".
     
  3. bobc455

    bobc455 Well-Known Member

    You gave all the information but the most important stuff!

    When you drive on the "street", is that on long highway trips at 80+ MPH? If so, 2.56s will suit you very nicely. Or, are you just doing 30 MPH to your local cruise and don't care about gas mileage? Then the 3.73s will work great.

    Do you drive it every day or just one weekend a month?

    Since you are 90% on the street, you should figure out what you will want where you drive it most (i.e. on the street).

    -Bob Cunningham
     
  4. sailbrd

    sailbrd Well-Known Member

    I wonder about your advance curve. Most of us have the distributor "all in" by 2200 rpms somewhere in the low 30 degree area. My setup is 22* at idle 34* by 2200 no vac advance. I wondered about the 22* at idle but do not have any starting problems and no knock.
     
  5. 87GN_70GS

    87GN_70GS Well-Known Member

    I'd say 3.42:1 .
     
  6. BILLY A

    BILLY A Well-Known Member

    Rear end gears

    Mike , You never said the tire size. I would almost be willing to bet you have 3.73 gears , 3000 rpm's @ 60 mph. If this is the case you already have a 3 point carrier and would save you having to buy one. With all the torque from a 455 you don't need a lot of gear. I have 3.08 ' s which are lovely on the highway and eith a switch pitch transmission i have a good bottom end. With TA Drag Radials i have a 1.8 sec. 60 ft. time. It's nice to drive @ 65 mph and only reve 2500rpm. Bill
     
  7. crazyjackcsa

    crazyjackcsa Big and Untame

    I'd say you couldn't go wrong with 3.23 or 3.42. If you did low speed crusing then 3.42. If it was alot of highspeed cruising, then perhaps even 3.08 or 2.93. A 455 really has no problem moving 2.93's on the street.
     
  8. D BERRY

    D BERRY 72 Skylark 2 DR POST

    Mike

    I run 2.56s and don't have nearly the motor you have and still run high 13s in a 4000+ pound car. Used to run 3.42s with the same combo and only lost .04 second by changing gears. I'd recomend 3.08s, they should be easy to come by, fit your carrier and make very little difference in your quarter mile times. Buick torque really gets it done so you really don't need a lot of gear. Heck I'm only pulling 2000RPMs at 60 MPH.

    Dave Berry
     
  9. 71GS455

    71GS455 Best Package Wins!

    Mike,

    That setup isn't far off from what I had in my Skylark before I spun a rod bearing this year (I do have the same cam, stock shortblock, very worked heads and matched intake). I was running a 2.56 open rear and went a 13.51 @ 106. That was going through the traps still in second gear!

    If you plan on doing a bit of drag racing, you may want to go with the deeper gear and run a taller tire on the street. It all depends on your rpm range and at what mph you plan to cross the finish line. The 3.73's would allow you to run a 28" tall tire and keep the revs similar to 3.42's with 26" tall tires. But at the track, you can run the 26 or 27" tall racing tires.
     
  10. mjoe7

    mjoe7 In the beginning God...

    I know I wondered the same thing. It seems to work fine. I gave them my specs and told them the buicks like it all in by 2500 and this is what they gave me.
    What do I do to get it in sooner than 3,000 rpm?
     
  11. mjoe7

    mjoe7 In the beginning God...

    Thanks for the help guys. I really appreciate it.
    It looks like 3.08's or 3.23's will be what I go with.
    Mike
     
  12. monzaz

    monzaz Jim

    gears...

    Well , if you want new for the 12 bolt you can go 3.08 or 3.42 or 3.55 that is it for low gears. 3.23 is 7.5 8.5 or old 8.2 BOP gears. They have factory 3.31 and 3.36 and you can find then new but you will pay dearly for them . I saw a new set of nos(new old stock) go for almost 400.00 OUCH!

    if your going to do more free way cruizin then go 3.08 if you want to feel alittle more power and pull and blow a bit more gas then 3.42 it. I think you would really like the 3.42 ...why have a old muscle car if you not gonna push it once in a while. Enjoy your hobby! :) Take care , Jim
     
  13. mjoe7

    mjoe7 In the beginning God...

    Thank's Jim.
    I will pm you later.
    Mike
     

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