The Stovebolt Site Forums The Shop Area Engine Shop 4/5 speed trans behind a 235

A friend that deals with hot rods recently ran somehing by me about backing my 235 with a 4 speed with an overdrive to save the life of my original 235 while keeping a somewhat original look. How hard would this be and what could i find that would bolt up? Thanks.


Zach

Well you could put a orignal 4speed in and Patricks Rear end kit. Just a suggestion. Do a search I am sure somewhere someone wrote about it.

Your 55 1'st should have an open driveline therefore you have a number of options depending on what transmission you have in it now, how much you want to spend, and what your skills are. You can replace the original 3 speed with a 3 speed OD which was available from the factory and will require some electrical components but no driveline mods. It is the closest thing to a "bolt in". If you currently have a 4 speed you could add a Gear Vendors unit which will require some driveline mods and a large infusion of cash.
Another option is a T-5 from a mid 80's S-10 which are quite popular. There are some mods required to the trans itself and to the driveline. There are a number of posts about all these units in previous posts in this forum.
Fred

So will the 3 speed over drive get my RPM's down, like the T-5 or will is still be winding out on the interstate? And how hard would the 3 speed OD be to find? Thanks,


Zach

The 3 speed o-drive has about the same amount of o-drive as the S-10 5-speed. Either will give the desired effect. They are hard to find though & some of the parts are very scarce. Beings you already have a floor shift I would go with the S-10. You can weld your old gearshift lever to it & make it look original. I've done 2 of them & they work great. There is a lot of info. on this website about the conversion.

I did the 3sp+od on advice from the dearly departed Jack Halton, past president of Inliners.org. I popped in the 3.90 from a '57 truck, it's a 3.90, just like what you have. The math is .70 (that's the overdrive) X 3.90 (your rear end gear) = 2.73. With 215 85R16 radial; tires I'm going 70 mph @ 2000 rpm's. That's with a '56 235. See below....

Just a suggestion.....do a little research on adding a .72 T5. I went that way and found it was economically feasible as well as great on the open road. My 235, .72 OD T5, 3.42 R&P and 28" tall tire lets me cruise effortlessly at 70 mph at 2000 rpms. The .72 5th will drop down to 45 mph and accelerate with no downshift or engine lugging. Your 55 1 series should have a 3.90 R&P which with a .72 T5 should work even better in the Greenville area. Your torque curve runs from 1600-2400. Plug in your numbers to this calculator to see what your setup would do:

http://csgnetwork.com/multirpmcalc.html

Also do a search to see how the S10 T5 install is done. I think you'll see that performance-wise and economically it is a very viable option.

Dave

I have a question on the T5 trans. I own a 54 3600 truck. My plan is to build a drivable workhorse. The S10 2.8 T5 seems a little weak. Can a T5 for the 4.3 or even the V8 motors be easily adapted in a similar way?

I used a T-5 out of a camaro V-8 with a S-10 tailshaft. The fine spline pilot shaft allowed me to use an 11" matched clutch assy from a big block. I just had to use a late model 235 or 261 6 bolt flywheel. The clutch is strong and extremely smooth.

What do you mean by a late model flywheel?

Whitedog there is another tough option for a 3/4 ton. Look into the GM version of the A833 overdrive 4 speed. They pop up freequently, and are tough as nails. An NV4500 would also be an excellent choice as it is a 5 speed with a granny low, and a .73 overdrive. I put one in my 59 GMC 1/2 ton behind the original 336 V8, and will also be putting one in my 1940 3/4 ton behind a well built 302 6 cylinder. The NV4500s are a bit pricey. They do a great job moving an old truck that still wants to work.

Is there an A833 OD with the old GM bolt pattern? Or can the OD gears be swapped into a case that fits my 216 bell housing?

Highflyer
Yes, there is. They were used in GM trucks, but I can't tell you the year. The bellhousing for those trucks actually has both the dodge and gm patterns drilled out. I believe the first year gm used the A833 they used the dodge case, and then later had a gm case cast.