1. Registration trouble? Please use the "Contact Us" link at the bottom right corner of the page and your issue will be resolved.
    Dismiss Notice

chevy 350 and differentials

Discussion in 'Intermediate CJ-5/6/7/8' started by tastful1, Nov 3, 2005.

  1. Nov 3, 2005
    tastful1

    tastful1 New Member

    Joined:
    Sep 29, 2005
    Messages:
    1
    I have a 1983 CJ7 that has been converted to a chevy 350. It has a 4 speed with a 205 transfer case. I really don't like the granny gear of the 4 speed, but start off in 2nd most of the time. The transmission is from a 3/4 ton chevy(sm245?) and for some odd reason the previous owner put in 225 differential gears and I have trouble keeping rpm up. Anyone have suggestions on new gearing? Want to get up and go and don't necessarally want to go over 90 MPH at top end in a CJ. I think my choices ar 373 and 410 on the top end. Also, any comments on carb vs. EFI. I have a 650 Holly now, but in the cold season it's hard to keep it running. I am in search of bolt on mufflers for Headman headers that will exit in front of the rear wheels. Saw some made for Jeeps but no longer manufactured. Like the rumble, but not a roar.
     
    tastful1, Nov 3, 2005
    #1
  2. Nov 3, 2005
    lynn

    lynn Time machine / Early CJ5 HR Rep Staff Member

    Huntingdon PA
    Joined:
    Sep 20, 2002
    Messages:
    3,437
    Use Header buddys to connect the muffler to the collector
    http://www.headerbuddy.com/
    Then use Thrush Turbo mufflers. Put a 90-degree bend pipe behind that to exit in front of the rear wheels. You'll have to measure to be sure this combo fits, alot will depend on the 350 placement and the length of the headers.

    You have a much-desired transmission with the granny low. Probably an SM465. Those of us that have trannies with the "granny low" do drive it like a 3-speed on the street: 2nd, 3rd and 4th. We use the low 1st gear when offroad only, and then only as the situation requires.

    225 gears? I don't think so... but being an '83, I'd imagine you have 2.73s, or 3.31 at best.
    The tire size you intend to run should determine what diff gears you select. 3.73 is about the higest gears (numerically lowest) useable for 33" tires, but is about ideal for 30 or 31" tires.
    4.10 or 4.56 work well for 33" tires.

    Fuel injection for your 350 should be easy to find and relatively cheap.

    HTH, welcome aboard!! :)
     
    lynn, Nov 3, 2005
    #2
  3. Nov 3, 2005
    timgr

    timgr We stand on the shoulders of giants. 2022 Sponsor

    Medford Mass USA
    Joined:
    Aug 10, 2003
    Messages:
    23,596
    I had 4.27s in my 304 V8 '73 with 31s (?) and was very happy with them. I'd suggest you pick your tire height, cruising speed, and target RPM and select the gears using that. A modern V8 would be fine between 2800 and 3200 RPM at cruise, IMO.

    http://www.novak-adapt.com/knowledge/gearing.htm
    The Novak site suggests 2200-2800 at cruise, but I think that's kinda low.
     
    timgr, Nov 3, 2005
    #3
New Posts