I have a sweet 54 3100 that has been restored with original 235 and it runs great. Only problem that I would like to fix is the gearing somehow. It has the 4 on the floor with a useless first gear unless you are towing the titantic and when i am cruisin down the highway it does not like runnin faster than 55 before it sounds like it workin too hard. I would like to be able to cruise at 65-75 and find a way to use that 1st gear. Would changing the rea end do this for me. I do not know very much about that subject and am looking for a solution to make this baby a perfect vehicle.
1st off... Welcome! Changing the rear ratio will indeed help, assuming that is even possible, based on what rear is in the truck, and what gear ratio it currently has. See this thread: https://talk.classicparts.com/showthread.php?t=9165&highlight=highway+gear If you would post the gear ratio you currently have, and the rear tire diameter, that will help. Not sure what ratio you have? Try this: To check rear end ratio jack up one tire if you have an open diff, or both tires if you have a working posi or locking differential. With the tranny in neutral (block the front tires first) rotate the jacked up tire one full revolution for posis and lockers and 2 full revolutions for open diffs. Carefully count the number of full revolutions the driveshaft makes. This is your gear ratio. In other words, if the drive shaft turns 3.9 turns, you have a 3.90 gear ratio. Turning the tire for twice the number of full revolutions and dividing the drive shaft revolutions by two will give you a more accurate reading. Hope that helps. John
I have just completed installing an s10 5 speed trans and an 06 Colorado rear in a 54. Check for my thread I am about to write on the install.
Your 54 3100 came with 3.90 gears in the rear. Joe, from Dead Zone Parts just got several sets of 3.55 ring and pinions and maybe some other ratios also. 3.90 to 3.55 is a BIG difference on the highway. You can't use the method John described to check the ratio because a 54 still has a torque tube. Patrick's offers a complete installaton package. You can convert your granny 4sp to an open driveshaft and then use a rear end with any ratio you care for. To keep your wheels you can use a 55-59 1/2T rear and our host offers 3.38 gears for these which is as low (in ratio) as you can go and still use as a truck. The Camaro/Firebird rears had had 2.75, 3.08, 3.36, and 3.56 if memory serves me and were the right width. They have a five bolt pattern so most use the early 50's car hubs to match the front and back.
John, Evan and others thanks for the information. I will have to wait till I get back down to Mesa to check out what is on the truck now. I believe it is the the original (probably 3.90) but it has 15" 6 bolt wheels (Cant remember exact tire size right now) I have driven it back and froth from Calgary to Mesa twice now at 55 in the slow lane on I15 and it would be nicer to have it running at 65 without over stressing the engine. I like having it in Calgary in the summer and Mesa in the winter (go figure)
Welcome Bob! There are several of us on here from AZ, so good to see another (even if it is only for part of the year). I had the same goal as you, but cant comment on how my mods have affected the ability to go highway speeds. I'm not quite done yet. But based on the MANY, MANY posts and forums I have read, I settled on a 71-80 Camaro/Firebird/Trans Am rear end. The width is within 1/2" of the original, and I now have 3.08 gears. Should be good on the highway. Won't know until it is driven. To sum it up, there are so many options out there depending on whether you want to swap the rear end out, change the gearing only, change bolt pattern, etc. Best thing I can suggest is to read as much stuff as possible on the subject, and see what you think will work best for you.
Calgary to Mesa... holy schnikey's, now that's a road trip! Sorry about forgetting the enclosed driveshaft, I'm more of 1st and 2nd generation C10 guy. If you know the tire diameter, the rear end ratio, and the transmission low and high gear ratio's there really isn't a lot of mystery in regard to the end result. I have a Muncie M-21 car transmission and 3.73 gears in my truck, but I also have 31" diameter tires. So what? Well I have to slip the clutch a bit to get it moving due to the "launch ratio" see below. The gearing and tire size though on my truck is great though for gas mileage. I'm a manual trans. guy and plan to install a heavier flywheel, which will help in my case.... but I digress, enough about my ole crate..... I'd suggest you use a ratio calculator, plug in all your data into it and see where you are. Here's a calculator for ya: http://www.4lo.com/calc/geartable.php Lots of other good calculators and data on the 4lo.com site too! Launch Ratio shouldn't be a problem with a granny gear. More information on that can be found here: http://www.5speedtransmissions.com/startlineratio.html Again, hope this helps! John
gearing I just completed swapping out my torque tube rear in my '54 for a '73 Nova rear. I also have a four speed with the granny first. I am amazed that you did that long cruise at 55 without blowing the engine. The engine positively SCREAMS at that speed with the stock driveline. I swapped out the back end of my tranny for an open drive so I could keep the original trans. The new gearing in the rear is 3.08:1 and I have to tell you that it is GREAT. Cruises at 65 on the hwy, start from a stop light in 2nd gear and the granny first is now actually usable when I need it. I can't say enough good things about the swap. You can check my thread on it. I also installed the Speedway disc brake conversion for the front and that is a vast improvement as well. Andy
