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Old 01-30-2019, 12:26 PM   #1
Pvmt-Pndr
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69 c50

I posted this over a month ago apparently in the wrong section.
I'm looking at buying a 69 C50 with a small block 350, manual trans (not sure which one) and a 2 speed rear end. I have 0 interest in keeping the 350 in it. I was thinking of swapping a for a carburated big block and a 4L80E with a stand alone controller. My problem in doing this is the 2 speed rear end. The more I think about it the more I'm talking myself out of it. I would have much more torque then the 350 would dream of having but I'm not sure it would be enough to make up the gears to just run it in high. Another option would be to make the 4L80E completely manual and use low 1,2,3,4 then pop it into 4hi once I got some speed going. That sounds like a pain to me since I would be stuck in hi gear until I came to a complete stop again. Swapping rear ends is also something that is on the table too for something with a fixed gear instead of the 2 speed if there is a fezable option please let me know. Most of this truck will be one off when I'm done with it and disc brakes would be nice anyways.

I'm open for opinions on the best way to drop a big block into it with an od trans. If I do get it (I'm certain I will). It will be used to pull my wife's 72 Chevy mega truck around to local bogs and later will be used to pull a 40' trailer with 2 mega trucks (when I get time to build myself one) plus gear so 20k pound load give or take.

I've been doing a lot of searching here and fortunately the truck does have the 10 bolt lug pattern.

I'm debating an axle swap from a 4500 or 5500 truck so I would have disc brakes all the way around.

The truck currently needs a booster/master cylinder. Since they're only $500 I'm just going to replace the whole set up so I can drive it around. I will be upgrading that also down the road.
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Old 01-31-2019, 01:58 PM   #2
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Re: 69 c50

ok - surprised no replies yet, so here's my perspective. I have a '70 C60 with the 366, 4spd and 2spd rear. While I thoroughly enjoy driving it, it is quite slow and tops out at around 52 mph empty. Fuel mileage really isn't worth calculating as there aren't many fuel stations that I pass by. The original brake set up works - certainly isn't like today's brake systems, but they do work. When I bought my truck I had planned to repower it with a Detroit Diesel, update the brake system to something more modern and basically feed my hot rod desires. However, after going through the truck, (it was all original ex-firetruck) I decided to pay homage to American History and leave it original and just enjoy the simplicity of it and the way things were in my childhood days. It is my go to vehicle when I just want to drive and not when I have to drive.

I know that doesn't even come close to providing any answers to your thoughts, but maybe it'll get some conversations started.
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Old 01-31-2019, 11:10 PM   #3
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Re: 69 c50

Quote:
Originally Posted by Nobighurry View Post
It is my go to vehicle when I just want to drive and not when I have to drive.
I know what you mean. As an old Hot-Rodder, some of my best cruises were in my all original 2-Ton and 3-Ton trucks.
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Old 02-01-2019, 11:34 AM   #4
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Re: 69 c50

Back in 70/71 I worked at a Sunoco station in Charlotte NC and we were the maintenance center for EZ Haul truck rentals. They were all 69/70 C30 350 400turbo automatics and C50 4 speeds single speed rear ends. The C50's all had governors on them. I had to go all over the south to bring them in to work on. I always disconnected the governor and those trucks ran at 65 no problem. So it's all gearing. Two speed rears are great if you really are gonna haul stuff. Plus they are fun to drive. It takes a little skill to master them. I also owned a 54 6400 Chevy 5 window that was originally a oil truck and I put a dump body on it. It had a vacuum 2 speed rear. That was even more fun as you need to work the gas pedal to make sure you had enough vacuum for it to shift. One year I had a reason to it run from southern MA to outside of Augusta ME about 10 times. Me and my 125 pound mutt. I enjoyed the crap out it!
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Old 01-31-2019, 03:02 PM   #5
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Re: 69 c50

I figured I'll put less then 1000 miles on it a year so mileage isn't much of a concern. It's more truck then I currently need. I could wasily buy a 1 ton truck and be ready to go but whays the fun in that. I'm thinking future plans and I love the look of it plus we already have a 72 K10 and a pull truck from the same era would be pretty cool looking driving down the road. Once I can narrow down a few things like what engine/trans I want to use which I'm leaning toward a p pump 12 valve and a G56. After having a 600 hp Cummins before they're hard to beat in my opinion.

I would really like disc brakes all the way around since I'll be pulling semi heavy for this truck later down the road. It will only be pulling around 10k pounds for the next few years. Most of which will be on the highway. Getting it capable of hitting 60-65 mph would be plenty fast enough for me.
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Old 02-01-2019, 02:47 PM   #6
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Re: 69 c50

I've done a lot of searching and reading all over the net. It seems like most don't take their trucks to the level I'm thinking. I figure this would be my forever pull truck. One thing upgraded at a time but I'm still looking for ideas and coming up with a plan. I do have the skills and the tools to do just about anything. If I don't have them then I know someone who does. I appreciate the responses so far.

I currently have a 366 at my disposal, it's in one of my wife's mega truck and that truck needs more power! That truck will be getting something a little special one day. Looking at the rated torque numbers of the 350 which is 325 and the 366 which is at 345 it's not worth it to me to do that swap for 20 ft lbs.

I'm glad to hear these things will run higher speeds but does that include the 2 speed rear end? You specified fixed gears. What rpm would the little 350 be turning at at 65 mph? I only ask because an engine swap and rear end swap would probably be the very last thing I do to it.

I assume it rides like a mule so I've been pondering weather or not to do a parallel 4 link with pan hard bar with 1-1/4" heims and air bags. I've built a few different suspensions. This would be the first parallel one since i believe it would be the best fit for the application. I'll do it to the stock rear end if I know it'll do what I want it to. Anyone done that?

I've decided I do want to stick with a manual transmission for sure. I like having control of rpms while towing.

Dumb question now... when shifting. I've driven split rear ends where the pattern is 1L, 2L, 3L, 4L, 5H shift to high 1H, 2H, 3H, 4H, 5H. That was much newer truck with a diesel. Is that the way to shift this C50 or is it 1L/1H, 2L/2H etc...?
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Old 02-01-2019, 03:39 PM   #7
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Re: 69 c50

Depending on your Trans, but I would say what you have would be the 1L/1H, 2L/2H, etc as you have mentioned.

My Clark 5-Speeds with the 2-Speed Rears had the more unusual pattern:

1L
1H
2L
2H
3L
3H
4L
5L
4H
5H

On the 2-Speed Rear, your Last Gear in the Trans and Hi Range on the Rear will give you 1 to 1.
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Old 02-01-2019, 03:45 PM   #8
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Re: 69 c50

Thanks for the info! Much appreciated. I would love to have an OD 5-speed. There's not too many options for it out there. A trans swap would be quick and easy. I need to do some more home work on what would be a good trans to swap into it. My transmission knowledge is very limited
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Old 02-01-2019, 09:30 PM   #9
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Re: 69 c50

Those EZHaul trucks didn't have a tach so I don't know what rpm they were turning but they were fine at 65.I can't imagine it can be hard to find a ring an pinion for that. That is the trouble with old Fire Trucks. Most were geared very low. They usually are great trucks to buy. I missed buying my towns 56 FWD 1 1/2 ton forest fire truck because I had two kids in college. Some guy in the midwest bought it.
C90 Bill is right. You split each gear. Very hard to split first. Also it shifts much easier when you keep in in the mid rpm range. Don't rev it close to it's limit, it just makes it harder to shift it. When you up shift, you pull the button up while it's still under a load then just let off the gas for about 2 seconds and then apply the gas gently until you know it is engaged. When you go from say 3rd hi to 4th low, do the same but use the clutch until you get your timing down. the gears in the diff just have to be going the same speed to engage, Just takes practice.
One of my Ryder Car Carriers had an air two speed rear end behind a non synchro 5 speed. I enjoyed it.
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Old 02-01-2019, 10:00 PM   #10
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Re: 69 c50

I actually looked up a YouTube video on shifting it. It is a bit different but nothing I'm concerned about not being able to figure out. Last shifting question... Is it geared too high to keep in high while driving empty? This truck I'm looking at someone has already pulled the dump bed off of, made a steel flat bed and threw a cab on the back so it's now an extended cab. That's the reason I want this particular one. I have my wife, daughter and niece who will be with me a lot of the time driving so the extended cab on it is a real selling point for me.
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Old 02-01-2019, 10:04 PM   #11
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Re: 69 c50

I only run high when empty. I also start in 2nd most of the time. I can be in 3rd before pulling through an intersection at times.
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Old 02-01-2019, 10:11 PM   #12
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Re: 69 c50

That's what I figured and was hoping to hear.

It'll probably be a month or so until I can get the truck home. I'm probably just going to have it hauled. A friend of mine has a semi and trailer. I appreciate all the responses guys. I'll let you know when she's sitting in my driveway!
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Old 02-01-2019, 11:28 PM   #13
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Re: 69 c50

I have a 1979 C70 Chevrolet with 4-53T Detroit Diesel, Clark 5 speed and Eaton 2 speed rear end. Its a blast to drive, tops out at 71 MPH, however I like cruising at 65 MPH. The hydraulic brakes (OEM equipment) are fantastic, not sure why anyone would upgrade them. I think they are powerful enough to stop a train! No issues with the rotors rusting when they sit idle. The brakes are so powerful you cannot get on them long enough to see any fade. I am sure if you were coming down Pikes Peak with a load it could be a problem. I would try the brakes before deciding they need to be changed. I usually shift all five gears then pop the rear end into high. Normally I just drop the rear end into low and I can top all the hills in my area. I think spitting each gear is just unnecessary wear and tear on the the rear. I used to drive a C50 (1972) with a 350, 4sp and 2 sp rear. The 350 was a great motor and I found it had plenty of power for 200 bushels of grain (11,000 to 12,000 lbs). It was a very long life motor and got good mileage.
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Old 02-01-2019, 11:15 PM   #14
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Re: 69 c50

Don't forget the pictures.
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Old 02-01-2019, 11:45 PM   #15
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Re: 69 c50

It's my understanding that after 72 the C class medium duty trucks came standard with disc brakes at all 4 corners. Correct me if I'm wrong please. My thought was if I upgraded it would be to disc brakes. I also want to upgrade the master cylinder just for the simple fact it is a single and if I were to loose a brake like then I would loose all brakes completely. It basically gives me the warm and fuzzies to know that there is always a backup.

I will have plenty of pictures for sure.

Last edited by Pvmt-Pndr; 02-02-2019 at 12:04 AM.
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Old 02-02-2019, 12:26 AM   #16
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Re: 69 c50

I understand regarding the single brake master cylinder. That is my only concern with my C70. I did rebuild the parking brake and use that as my emergency brake. I have tested it and it appears to be able to stop the truck. I am sure it would fade quickly, however it is an emergency backup. The 1972 I drove had drum brakes all the way around.
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Old 02-02-2019, 12:38 AM   #17
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Re: 69 c50

Making sure the parking brake is high priority on my list prior to the upgrading. That way there is always a fail safe. Fortunately the truck will not be driven without a trailer with trailer brakes hooked to it often at all.

I had back surgery less then 2 months ago and it's delaying me a lot with this truck.

Once I figure out how to upload pictures I can post some of the previous trucks I built. The last one was a 53 Willys pickup that wasn't intended to be pretty at all. I ended up doing a body swap from an 89 econoline that had a 460 in it. It was supposed to be my mega truck but someone came along and fell in love with it and money poured out of their wallet... I never got the chance to finish it.

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Old 02-02-2019, 11:17 AM   #18
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Re: 69 c50

He is right about not splitting each gear. I doubt you will ever have a load so heavy that you would NEED to do that. Start off in low axle and that kind of saves your clutch. Splitting the top gear is usually all you need to do. The most you should have to do is split the top two gears. Most of the time you will only need to down shift the axle to keep your speed up. I have driven these trucks with 292 6 cylinders and you have to shift more but that 2 speed can keep you in your power band much better.
As far as the brakes go, I can't ever remember thinking they were not enough. Just make sure that they are adjusted correctly. Same for the parking brake. The lever that you set the brake with, the end of it twists to adjust it. When you get to work on it, back off the the handle in the cab all the way, then go under the truck and adjust it underneath so it's tight but not dragging, then you'll have plenty of adjustment from within the cab. The parking brake is located behind the transmission, on the drive shaft. You'll see that they too are a simple form of drum/shoe setup. When adjusted properly, they work great.
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Old 02-02-2019, 11:58 AM   #19
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Re: 69 c50

Thanks that's good to know! I'll take any tips and tricks anyone wants to offer. I'm trying to learn as much as possible and get a solid plan on what I'm going to do now and down the road. I know I will definatly be putting in a 5 speed trans once everything is ironed out with what I have.
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Old 02-02-2019, 12:07 PM   #20
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Re: 69 c50

I never use low gear in my 5 speed. I guess If I needed to pull down a building or remove a tree it might come in handy. The C50 I drove had a 4 speed which was perfect. I never wanted more or less gears.
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Old 02-02-2019, 12:21 PM   #21
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Re: 69 c50

Later I'll be moving to the mountains and pulling 20+k pounds so the extra 2 gears in a 5 speed I'm sure will make a big difference. I just have to narrow down what 5 speed it is that I will want to use.

The body on the truck is in great shape so it will be mostly a mechanical build instead of cosmetic. I do plan on putting a lot of lights on it since we do get stuck loading or unloading at night a lot.

Once it's in my driveway I will get it going and drive it around once in a while and see what I feel it needs to make exactly what I will be using it for a little better.
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Old 02-02-2019, 05:41 PM   #22
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Re: 69 c50

I'm a little different.

If it has a gear, I'm using it, lol.

Although I never split the Granny gear.
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Old 02-03-2019, 12:37 AM   #23
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Re: 69 c50

I would usually use all the gears also but it's depending on how everything is geared and what I was doing. I had a 91 Dakota over 10 years ago with a 5 speed no OD and a 3.9 V6 most of the time 1st, 3rd and 5th was how I shifted it. I really only use the clutch when I took off with most of the manual transmissions I have owned. I haven't owned a manual trans in a few years and I do miss it.

I do not have any pictures of the engine on the C50 but what I've been reading is that on the hood there are 2 vents for the 427, 1 vent on the drivers side and no hood vents on the small block or straight 6. I find it fishy because this truck has 1 vent on the drivers side. Either what I have read is wrong, someone put it in it or the current owner doesn't know what they're looking at. I'm trying not to bug them anymore then I have to before I can actually get down there to get eyes on it. It's 2 and a half hours from me and I'm not sure I can sit for a 5 hour round trip with my back yet. It's been almost 8 weeks since I had back surgery and I feel pretty good until I can't get up and move around when I need to.

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Old 02-03-2019, 09:41 AM   #24
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Re: 69 c50

The trucks that had a vent on each side of the hood came with the 427. The ones with a hood vent only on the drivers side came with the 366. No vents were small blocks or 6 cylinders

Last edited by Nobighurry; 02-03-2019 at 09:47 AM.
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Old 02-03-2019, 03:11 AM   #25
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Re: 69 c50

Starting in a Low Gear (not necessarily the Granny gear) is also easier on the Clutch as NewBayColony has mentioned above. The truck manuals also recommend starting in Low Range with a 2-Speed Rear, but I agree that it won't ruin your truck if you don't. Some Transmissions like the SM 420 and SM 465 4-Speeds, I always start in Granny 1st. To me 3-Speed shifting is for Manual Shift cars, lol. Seems to work, I never wore out a Clutch yet.
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