The Stovebolt Site Forums The Shop Area Driveline Best tranny swap for my 54 3100?

First project truck and still learning a lot, but I need advice from some of you pros. I've got the inline 6 235 in it and plan on keeping it that way. It's a manual 4-speed with the granny gear. I have to be in 3rd gear running down city streets, sometimes even 4th. Would like to feel comfortable taking it on the freeway. What's the best bolt-in tranny swap? Do I need to change the gear in the rear end? Should I do both a tranny and the rear end? Recommendations?

I did the T-5 in my 54 3100, used it with a rear end out of a 62 chevy 1/2 ton with an Astro van drive shaft. freeway speeds all day long.

Hooker:
Don't know alot about these kinda things..but I also have a 54 3100 with a 4 speed...have been on this forum for afew months and reading alot...I have been given the advise of switching the rearend gears to a 3:55 since my truck only goes about 48 on the highway. I would switch the rearend and give it a go before spending coin for another Tranny. Just might do the trick. I'm sure other folks who have done the switch will pipe in with their experience.
Would love to see some pics of your 54..have you posted any on photobucket? ( Free site ).
You can always PM me if any questions..since we have same truck and are trying to fix them up.
Thanks

Sorry...Glasses need cleaning...Hookem...NOT Hooker

I just turned over 13,000 miles in my 235-54 truck with a .72 T5, 3.42 Camaro (62") diff and 28" tall rear tires. My cruise speed is 70 mph @ 2000 rpms and the truck is on the road every week.

I'd suggest you check out my WEBSHOTS albums: "Shoebox and Tips and tricks" that goes into detail about the conversion. One thing I might add is that if you wanted a lower cruise speed you could retain the 3.90 R&P in the stock 54. This would put you a little deeper into the torque/power curve at a lower ground speed which would improve the overall efficiency of your engine. Some of the folks that have made the R&P chunk modification can fill you in on the details. Feel free to PM if you have any questions.

Dave

I appreciate everyone's inputs...I'm thinking changing the gearing in the rearend might be what I go with to start. I'm going to get some pictures up soon.

If you want to increase the speed of your vehicle, have you considered what it will take to stop it? The brakes that came out on your truck were designed to stop it at the speeds that it was designed to run at.
Just something to think about.
Jim

3:55 gears and radials,best money you will spend,along with a late year 235.

Change your rear end to 3.55 first then you will not need to do anything else. Go to Patricks web site.

Hookem, if your present gear ratio is 4.11, changing to 3.55 will not vastly increase your freeway cruising speed. I did that conversion on my '36 Chevy pickup recently and it is definitely an improvement but the change is 13.6%, not a huge amount.

The 3.55 gears were used in some '50-'54 Chevy cars so if you're open to using a car rear axle in your truck you won't have to buy that expensive gear set from Patricks.

If the rear-end is stock 1954 it would be a 3.90 and switching to a 3.55 would drop your cruising rpm only a little less than 300 rpms.

It's a good idea to crunch your own specific numbers when planning upgrades for your vehicle. Bear in mind that the stock 235 has a torque curve that starts at about 1600 rpms and effectively tops out at about 2500 rpms with 2100-2300 giving you the optimum efficiency. After that you're just making additional noise and sucking the life out of your 4 main bearing engine.

Try plugging your numbers into this calculator:

http://csgnetwork.com/multirpmcalc.html

In reality, you'd have to drop down to a 3.08 with the 1:1 4th gear to give you 65mph at 2400+ rpms with a 28" tall rear tire. If you really want to use your truck on the open road you need to consider retiring the sm420 and upgrading to something that makes a safe 300 mile over-the-road trip a fun experience.

Dave

The torque/hp cross-over point for a 1954 235 truck engine is about 2,500 RPM. My Suburban has the 3.55 conversion and 215/85x16 radial truck tires that have a loaded diameter of abut 31.5 inches. I can comfortably cruise 300 miles at either 60-65 MPH (2450 RPM) and get about 18 MPG, or at 65-70 MPH (2650 RPM) and get about 12 MPG. I bought a speedometer adapter for about $100 - it's nice to know how fast your are going (as a policeman told me before I got the adapter).

I realize that the improvement provided by the 3.55 was not very much but it allows me to keep it looking original (different strokes for different folks).

The improvement in interior noise was noticeable to me and my passengers, even though my interior noise was quite low before the 3.55 conversion. I strongly recommend using the gear/bushing/etc installation kit if the 3.55 conversion is being done.