Need some advice with my 67'!

[lawjack]

Alright so this summer me and my dad swapped in a 350, and kept the old 3 speed trans. I have no clue what my rear end ratio is but my best guess is 3:73. The rear end is not original to the truck, back in the 90s my dad had this one swapped in when his old one crapped out on him. At 60 MPH im turning about 2800-2900 RPMs. This seems pretty high to me, i need some advice on which direction to go.. A new trans or swap rear end gears. I do travel lots of interstate miles because i have to drive about 220 miles to college every now and then, and thats not too fun at 55 MPH.

[Frijolito1988]

Check out this thread, lots of good info in there.

http://67-72chevytrucks.com/vboard/s...d.php?t=542702

[CC69Rat]

A good 700R4 with 1:1 lockup and more of a cruise gear would help a bunch IMO.

[truckster]

If you've got the money and the inclination to do some work, a 700R4 is a good candidate. You really need to figure out what your rear end ratio is. It's not hard:

Put the trans in neutral.
Jack up one of the rear tires.
Make a mark on the tire and and on the driveshaft.
Turn the wheel until the driveshaft makes one complete rotation
Count the rotations of the wheel.

If the wheel makes 3 3/4 rotations, you have a 3.73. If it's slightly more than three, it's likely a 3.07. If it goes a little more than 4, it's a 4.11, and if it goes about 4 1/2, it's a 4.56. Those seem to be the most common ratios.

[lawjack]

Originally Posted by truckster

If you've got the money and the inclination to do some work, a 700R4 is a good candidate. You really need to figure out what your rear end ratio is. It's not hard:

Put the trans in neutral.
Jack up one of the rear tires.
Make a mark on the tire and and on the driveshaft.
Turn the wheel until the driveshaft makes one complete rotation
Count the rotations of the wheel.

If the wheel makes 3 3/4 rotations, you have a 3.73. If it's slightly more than three, it's likely a 3.07. If it goes a little more than 4, it's a 4.11, and if it goes about 4 1/2, it's a 4.56. Those seem to be the most common ratios.

Thanks for the advice I will definitly do that this weekend, and i do like the idea of a 700r4 except i dont want an automatic. I've heard of people swapping 5 speeds i think T5's out of s10s in our trucks. Is this fairly doable?

[GASoline71]

The T5 out of an S10 or a Camaro are weak transmissions for a heavy old truck if you ask me. There are better 5 and 6 speed transmissions out there.

Gary

[lawjack]

Originally Posted by GASoline71

The T5 out of an S10 or a Camaro are weak transmissions for a heavy old truck if you ask me. There are better 5 and 6 speed transmissions out there.

Gary

Okay, well im really wanting to stick to something manual so hopefully i can come up with something thats not too weak for my truck, and can get my down the interstate better. Thanks for the help

[GASoline71]

There are cats that do use the T5's in these trucks... there is even a "how to" Camaro T5 install on here somewhere.

But me personally... with the way I drive... I would want something way stouter. Especially if the truck is used for any kind of towing or hauling.

Gary

[lawjack]

Originally Posted by GASoline71

There are cats that do use the T5's in these trucks... there is even a "how to" Camaro T5 install on here somewhere.

But me personally... with the way I drive... I would want something way stouter. Especially if the truck is used for any kind of towing or hauling.

Gary

Well it definitely doesnt do any towing or hauling, other than hauling my stuff up to college and back, which isnt much. But i am pretty hard on it and like to get on it every now and then.. Would a 4 speed help me at all? i've gotta buddy who keeps telling my to look for like a muncie 4 speed, but im confused if final gear in a 4 speed and a 3 speed is 1:1 there wouldnt be any difference in rpms in final gear would there?

[truckster]

No, if you're concerned primarily with highway driving, the final gear ratio is what matters. There are some later-model 5-speeds with overdrive that can be swapped in, but I believe you have to fabricate a mount for the hydraulic clutch.

As I've gotten older (I hate to admit that) I've come to appreciate the automatic more. Only one of my six vehicles has a manual, and that's a little Geo Tracker. But I understand your wanting to mix it yourself.

There are some good older threads on the forum. I'd do a search for manual trans swap and see what you come up with.

[oldblue1968chevy]

Run it like it is! lol

t-5
200r4
700r4
nv3500
nv3500

all GM OD trans auto and manuals

[lawjack]

Originally Posted by oldblue1968chevy

Run it like it is! lol

t-5
200r4
700r4
nv3500
nv3500

all GM OD trans auto and manuals

Thanks! well for now i think im just going to take your advice and run her like she is and just take my time cruisin on the interstate!