vinnyv

I have a '58 with a '59 283 / 230 HP with a 3 speed. My tranny is quite noisy at this point and is difficult to shift into second as well as back to neutral. Sounds like a bearing noise. I have a Hurst 3 speed shifter currently. My question is, what is involved in converting this to a 4 speed? What tranny am I looking for? I have been advised to look for a T-10 with a close ratio. What I would like is better gas milage from this car. I believe I have a 411 rear but not positive. A friend of mine has a 3.70 and a 3.5? he said he will give me if I want. At 55-60 MPH, I am turning about 3000 RPM's. Don't know if that's good or bad for maximum fuel efficiency. (Like to use the car on the open road)
I have looked on Ebay, etc for a 4 speed but the years and types are all over the place. I see references to # of splines and lines around the front shaft but I really don't know what I am looking for or what will fit and what will not. I have what is refered to as a 2 piece main (?). Everyone makes this sound so easy. I have removed trannys years ago and it was simple. Is there a unit that will be a direct swap without modifying anything else? Will the existing drive shaft fit? Is there anything I can buy NEW as an after market (ie Summit, Ecklers, etc.) that will go right in? What shifter is recommended? I appreciate any advice on this subject.
Thanks,
VinnyV

wmf62

the conversion will be simple, just a matter of getting the right shifter for the transmission you choose.

if you're just going to drive it, then personally, i'd go with a wide ratio M20 Muncie (it's stronger than a T-10 and probably easier and cheaper to find) and the 3.55 rearend ratio. close ratio transmissions are not good for the average driver unless they're running a 4.11 rearend.

neither a wide ratio or a close ratio trans will change the 'down the road' rpm as 4th is 1 to 1. you will have to go to an overdrive transmission to cut down your road rpm's if you want to keep your present rearend ratio.
Bill

DZAUTO

Vinny,
Your options are fairly wide.
First, the swap that would be the easiest and most direct would be to locate a 57-62 Borg-Warner T-10 4sp (this is the 4sp tranny used in all Chevys during that time frame). The existing driveshaft yoke will fit the T-10. The T-10 is the same length as a 3sp, so no issues there. You will need to round up a shifter for the 4sp (either an original type T-10 shifter or a Hurst shifter). A 63 T-10 will also plug right in, except the splines on 63-later trannys were changed to a finer spline (27 splines), thus, you would simply need to change the yoke on your driveshaft.
IF you were to locate a 62-63 T-10, then you would also need to buy an adapter mount plate (sold by all the aftermarket sources for about $20) for the mount on the tranny tail housing. This plate was unique to 62 Corvettes only. Too easy.
Next, the Muncie is a good, strong (generally stronger than a T-10) 4sp that was introduced in GM cars in mid-63 to replace the T-10. The 63-70 Muncies are the same length as a 3sp or T-10 and they also have the fine spline tail shaft. To install a Muncie in your car, the easiest solution for a shifter is to buy a Hurst, and, if you like the original look of a factory shifter, buy one of the replica shifter handles for your car that is designed to bolt onto a Hurst shifter.
A Muncie is probably going to be a little cheaper and easier to locate than a T-10 because they are much more common.

A car with a 4.11 rear is without question more fun. But with today's gas prices, it is no longer practical. Chevy made rear gear ratios from 3.08 to 4.56 that are a direct bolt-in swap for your rear. These rears were common to the 55-64 passenger cars and 56-62 Vettes. If your buddy will GIVE you a good 3.55, I'd jump on that in a heartbeat!!!!!!!!! Your 283 should handle a 3.55 gear (with a wide ratio 4sp) with ease. A close ratio would be a better match to your 4.11 rear, but, since BOTH wide and close ratio 4spds have the same 4th gear (as well as 3rd in a 3sp) which is 1:1, your gas mileage won't change. ONLY a change in gas mileage for your car will occur with a rearend gear ratio change (unless of course you install a tranny with an overdrive which is a whole other challenge!).

Opinion: If I were in your shoes, I'd locate a wide ratio Muncie (M-20) of 66-70 vintage, Hurst shifter with a replica handle, 62 Vette tranny mount adapter plate, change the yoke on the driveshaft and do a rearend gear change. All of that would be essentially a bolt-in swap and would be trouble free (if you could locate a 3.36 rear ratio, that would help gas mileage a little better, a 3.08 gear very possibly would be a little too much gear for your 283).

jbar1

I own a '58 with a 283, T-10 4-speed that had a 4:11 posi unit in it and when doing 65 on the turnpike, my rpms were around 3600. I finally switched the rear to a 3:08 and now my rpms at 65 are around 2400. The 283 has no problem with this switch, however I can no longer accelerate smoothly in 4th gear from 20 miles an hour. By the way, my gas mileage is 20 plus miles per gallon, dependent on whether city or highway. I'm glad I made the switch and have no regrets.

vinnyv

Thanks all for the quick response. I have one more question. I am seeing 4 speed Saginaw tranny's in my search. Is this any good? (I believe that my 3 speed is a Saginaw) Does it fit right in or is modification required (other than the shifter)?
Thanks,
VinnyV

GCD1962

lst gear in the Saginaw 4-speeds are too low, approx 2:81. For info on muncie trans go to

http://www.autogear.net/orderform/4speedpricing.htm

DZAUTO

Forget the Saginaw 4sp. Also, they were only a cast iron tranny, and weigh a ton!