HELP!! need a 4rth gear or different gears

Hello everyone..I got 65 dodge a100 three on the tree..on the freeway sound horrible..I think I need another gear.or different rear gears...any advice would be appreciated..thanks

 

Depends on how much you want to spend. Changing rear gears would be the cheapest and easiest but gear selection might be limited for the stock rear end. Anything close to 3:23's may be a good all around gear.

 

maybe you just need a muffler.

 

Most 4 speed will have the same 1 to 1 gear ratio in high gear as your 3 speed. If you want an OD trans, it is a 5 speed you need. Or one of the 3 speed with OD 4th gear trans. A rearend swap is probably easier, I am guessing you have the 8.75 rearend? If so easy as swapping out the pumpkin, similar to Ford 9-inch.

 

I put 275/60/15s (on 8 1/2 slots) on my '69 A108 and that helped loads