Finally got a running 65 C10

[1low4x4]

Covers came out good

 

[DoubleDingo]

Covers came out good

Yes they did!

 

[1low4x4]

So if I was to start looking for a 4 speed manual transmission what would I be looking for? Assuming the clutch pedal would still work I’d just need to mount the shifter in the floor because now the 3 on tree wouldn’t work right.

I don’t mind manual, it would actually be neat to keep it but I’d like another gear

 

[legopnuematic]

65 is a Z bar clutch isn’t it? Or is it a hydraulic clutch like the earlier 60s trucks?

Depends on what you want, if you want a “true truck trans” the SM420 would be the correct 4 speed truck trans for one of those trucks. About a 6:1 first gear and 1:1 fourth. No shifter needed as it’s part of the trans itself.

For a “sportier” four speed, the NP833 is an aluminum cased 4 speed with an overdrive. It’s a “Mopar” trans that was an option in 80s squarebody trucks. 3.09:1 first and 0.73:1 fourth. If you went this route be sure to get the shifter, as the GM shifters are not reproduced and are somewhat difficult to come by.

Then there is the “traditional” four speeds like a T10, M20, M21, M22. Non overdrive.

An NV3500 5 speed could be a decent candidate.

 

[DoubleDingo]

So if I was to start looking for a 4 speed manual transmission what would I be looking for? Assuming the clutch pedal would still work I’d just need to mount the shifter in the floor because now the 3 on tree wouldn’t work right.

I don’t mind manual, it would actually be neat to keep it but I’d like another gear

If you're going to go 4 speed, I would highly recommend the sm420, and depending on your rear end gears, 3.54/3.55 gear ratio. Trust me, that truck would be a blast to drive like that. A really good take off gear, still only three shifts for regular driving, bulletproof transmission, and the gear ratio is great for cruising and hauling @$$. I say this from experience with Mean Green. It was a 4.57 truck with the sm420, until I found a 3.54 axle and swapped it in, and I broke some land speed records with that truck after that.

25 years ago, visitation weekend, living in a new town and 2.5 hours to get home. My girlfriend in my hometown said be there by 5 we're going out to dinner. I was running late, left my brother's house at 3, still had to stop for gas before hitting the road. Filled the tanks and was at her door in 2 hours.

A few years before that, was running late, dang I see a theme here...lol... Work was a 17 mile drive and I had 15 minutes to get there or I was late. From my driveway to the work parking spot, 8 minutes!

If you swap to a better gear ratio, install a front sway/stabilizer bar, and if you can find one, a power steering conversion kit with a smaller steering wheel. Unless you want to keep the school bus steering wheel and manual steering steering gear. Manual is fine as long as you have good tires, and rims without alot of offset. I ran Mean Green with a Grant steering wheel and the manual steering for many years. Converting to power steering was a game changer and installing the front sway bar made that truck handle like a sports car, kinda...lol... It still handled great for a 3/4 ton truck with that setup. Yours being a short bed stepper, it just needs a little tweaking to make it better.

A schoolmate had a 65 like yours, his dad built the engine, I think it was a 327, had the sm420, and I don't know what rear end ratio it had, but it would beat all kinds of cars in races.

Not saying you want to race your truck, but having more legs if needed is a plus.

 

[DoubleDingo]

This will give you the rpms with different gear ratios for your truck if you use a 30.5 inch diameter tire....

 

[DoubleDingo]

The land speed records I mentioned was with a stock 350, ram horn manifolds, dual exhaust that exited out the passenger rear corner, but a dual-in dual-out Borla muffler in the cavity where an auxiliary side tank would be mounted if they mounted them on the passenger side. The Borla muffler helped with the scavenging effect. Quadrajet carb, timing and carb tuned for race because I did mostly highway driving. Once in awhile I would go to the airport and get 5 gallons of 100LL and top off the tank with high octane pump gas. YEEEEHAWWWWW! Talk about throttle response!

 

[bucket]

Another option would also be the lowly Saginaw 4-speed. Still no overdrive, but better gearing and 1st gear is synchronized. And affordable.

 

[DoubleDingo]

Another option would also be the lowly Saginaw 4-speed. Still no overdrive, but better gearing and 1st gear is synchronized. And affordable.

The only problem with the 4 speed is it's basically a 3 speed with one extra gear. It needs 4.10s for rear gear so 1st doesn't slip the clutch so bad at each stop. The sm420 you're only using 2nd thru 4th, and 1st only if needed, 2nd is a great takeoff gear.

 

[DoubleDingo]

This will give you the rpms with different gear ratios for your truck if you use a 30.5 inch diameter tire....

FYI: The overdrive in that pdf is a Ranger gear splitter. Everything else is purely sm420 and the various gear ratios. I forgot that file had the overdrive info too.

 

[1low4x4]

Thanks, something to think about.

Nephew got the heads ready for paint, showed him the tape and file trick I learned from a hot rod magazine decades ago. Gonna look sweet

 

[bucket]

The only problem with the 4 speed is it's basically a 3 speed with one extra gear. It needs 4.10s for rear gear so 1st doesn't slip the clutch so bad at each stop. The sm420 you're only using 2nd thru 4th, and 1st only if needed, 2nd is a great takeoff gear.

I don't understand this logic? They were used in cars like Impalas with highway gears that were probably heavier than short, 2wd C10's. How would it be any different than taking off in 1st with the stock 3 speed, or 2nd (1st after granny gear) in the 420?

 

[bucket]

There were also different ratios used in the Saginaw 4-speed. They can be identified by the number of grooves on the input shaft.

 

[Ricko1966]

I understand the logic of the sm420,you have a low,low 1st gear when you need it and a 3 speed for daily. So you can run less rear gear but still have a deep gear ratio,when needed.

 

[bucket]

For a fun driver, I personally would much rather have a trans with a 1st gear that is ideal at all times, as opposed to one gear that is too steep most of the time and another gear that is too tall most of the time. I'm under the impression that this is in no way shape or form, a work truck.

I'll just leave this here...

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