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Technical 308 gear for 235??

Discussion in 'The Hokey Ass Message Board' started by Medic4lifejr, Dec 10, 2020.

  1. Medic4lifejr
    Joined: Jun 30, 2016
    Posts: 65


    Hi I have 53 converting to open driveline, found a good deal. 64 rear end from a Nova, schematics show a bit narrower 57 3/4” width. Feel it will be good setup because the current wheels I have, I had to trim my fender skirts. Wondering running 308 gear be good for stock 235 3 speed??
  2. Rusty O'Toole
    Joined: Sep 17, 2006
    Posts: 9,519

    Rusty O'Toole

    Should be ok if you use smaller diameter tires as the Nova did. Or with stock size wheels and tires it will make a smooth hiway cruiser with not much pickup in high gear. In other words, like an overdrive. The highest stock gear for that car and engine, was a 3.55:1 in Powerglide models.
  3. Running those gears in other 56 with stock 235 and stock 3 speed. It does great on the highway and rolls out well. The only issue is when you'll need first while still rolling. The deep gears will require some pedaling while still in second but I'm aware of why and accept it. The other alternative would be to come to a full stop, but, traffic from behind doesn't always allow that.
  4. Vegas is flat country so it should be ok.

  5. jimmy six
    Joined: Mar 21, 2006
    Posts: 9,013

    jimmy six

    Since that rear end calls for an open drive shaft. What are you going to do for a trans. Your bellhousing won’t allow a different trans that has one. A 55-62 235 bellhousing will bolt on after you remove the flywheel. Then a set of side mounts may be needed or if you get a rear mount trans to adapt to your old rear crossover a stock steadier on the right side will work.
    I put an open drive in a 50 using a 59-235 and a Vega 4-speed with a 3.10 low. We put in a 56 rear end with a 3.08 from a 62. And it was great but a lot of work. Good luck...
    Medic4lifejr likes this.
  6. Medic4lifejr
    Joined: Jun 30, 2016
    Posts: 65


    I have found 55 three speed one with and the other without mount on the tail of the transmission. Was able to also find the bell housing for them.
  7. I changed my 53 Chevrolet 261 Chev. 6 to open drive with a 3:70 ratio 57 Chevy rear and a Corvette 3 speed.

    I changed to a 3:50 third member huge mistake!! When I step on the gas gas pedal it's like stepping on a wet sponge. There is no torque, or throttle response.

    I am going back to a 3:70 with a Posi.
  8. squirrel
    Joined: Sep 23, 2004
    Posts: 48,672

    Member long as you never leave the valley. Then all bets are off.
  9. ekimneirbo
    Joined: Apr 29, 2017
    Posts: 1,901

    from Brooks Ky

    S10 rears are pretty cheap and might even find a posi out of a Blazer .....which is a little wider. Probably $100 or so will get one.
  10. 1934coupe
    Joined: Feb 22, 2007
    Posts: 4,492


    3.05 gears and a 235 6 cyl, I know I wouldn't do it.

    belair likes this.
  11. '60s era GM 6 cylinder trucks typically had a 3.08 gear. You should be fine. it won't have much of a hole shot but if that was what you are after you wouldn't be running a 235 anyway.
    pitman likes this.
  12. Budget36
    Joined: Nov 29, 2014
    Posts: 6,399


    I had 3.55’s in my PU with granny tranny. I always wished I had more gear for the highway, but taking off in 2nd was kinda the limit of what I wanted. Personally I think a T5 with the 3.55’s would have been a good fit.
    I bring this up because as mentioned earlier, your 1st gear and 3.08’s might be hard on the clutch
  13. anthony myrick
    Joined: Sep 4, 2009
    Posts: 7,628

    anthony myrick

    Ran 355s with mine. Full syncro Saginaw 3spd.
    Loved it. This was with a 235/75/15 tire
    I just plan on changing the 3spd for an OD
    The only way to find out if you like it is to drive it. We all have different driving needs.

    Had a 300-6cyl ford with 275s. Hated it.
  14. BamaMav
    Joined: Jun 19, 2011
    Posts: 4,866

    from Berry, AL

    My old man's 71 C10 had a 250 with the 3.08 rear. Had plenty of power and road speed, but you're down a little on cubes with the 235...
  15. I'm channeling an old memory so maybe someone can help me out.. . Food for thought: I'm to understand the diffs from the '55 thru '64's rearends will interchange, but was warned to ignore the Nova ones as they are of a lighter/weaker construction. Not sure if that applies to the axle housing also or not. If you aren't planning any spirited driving, may not matter anyway, but just throwing it out there...
  16. 1934coupe
    Joined: Feb 22, 2007
    Posts: 4,492


    Gotta56 the early Nova's 62 anyway had 4 lug wheels and axles but I don't think the housing or diff. was any different. That is my old memory.

  17. seb fontana
    Joined: Sep 1, 2005
    Posts: 6,954

    seb fontana
    from ct

    Early Nova's weren't integral, I can't remember a drop out chuck.
  18. junkyardjeff
    Joined: Jul 23, 2005
    Posts: 7,906


    I had a 2.79 behind a 235 for awhile and it was not too bad but the 4.03 first gear in the T-5 is what helped it but could never put it in fifth.
  19. A T5 trans with the lower first gear ratio would be better. But use what you have and make a determination later if you need to make a rear gear ratio change.

    Sent from my SM-G950U using The H.A.M.B. mobile app
  20. five-oh
    Joined: Jan 10, 2008
    Posts: 411

    from Arkansas
    1. HAMB Old Farts' Club

    I just did this swap in my '52 3100. 12 bolt with 3.08 (out of a late 70's K10), swapped the closed drive line SM420 for an open drive line SM 420, all behind a '53 full pressure 235 that originally was in a Power glide equipped Bel Air. I haven't put more than around 150 miles on it, but so far it's just what I wanted. Seems to really be a good cruiser at 65 to 70, and I start off in second. (Still have granny low if I need it). I don't pull much more than an 8x10 trailer with a lawn mower on it, and mainly just wanted a cruiser that could run highway speeds. I live in Arkansas, so no really big mountains to pull either.
  21. junkyardjeff
    Joined: Jul 23, 2005
    Posts: 7,906


    I have found those pre 59 235s are not designed to go slow,its been a battle to get the 57 235 I have in my 37 to run its most efficient even with 3 .55 gears now. I am thinking it should get around 20 but its best has been 16,messed with the jet and power valve spring and then came to the conclusion that the 57 truck 235 was designed for 4.10 gears and that is the best its going to be. Now I was told in 59 the cam was changed for more low end torque so I hope the 60 235 my 37 is going to get will be a little better running at slower speeds.
  22. wicarnut
    Joined: Oct 29, 2009
    Posts: 6,752


    I believe the 50's Chevy 6 stick cars came with 4:11 as I got several from junkyards back in the 60's, all 6 stick cars.
  23. pitman
    Joined: May 14, 2006
    Posts: 5,046


    Did run a 3.08 behind a wide ratio Muncie. The low first gear in a wide ratio was magic. In a light model A worked well.

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