Strandrunner Posted September 9, 2016 Report Share Posted September 9, 2016 New to this stuff: I just got a 56 Truck and I want replace the stock 3 speed flathead 6 with a 360 Mopar and overdrive. Will I have to change the differential? What else will I have to change? I am trying to estimate the total cost to do this. thank you for your help 1 Quote Link to comment Share on other sites More sharing options...
Young Ed Posted September 9, 2016 Report Share Posted September 9, 2016 7 hours ago, Strandrunner said: New to this stuff: I just got a 56 Truck and I want replace the stock 3 speed flathead 6 with a 360 Mopar and overdrive. Will I have to change the differential? What else will I have to change? I am trying to estimate the total cost to do this. thank you for your help Nice truck. From my experience come with an estimate and then double it to account for all the little stuff that comes up. 1 Quote Link to comment Share on other sites More sharing options...
Strandrunner Posted September 9, 2016 Author Report Share Posted September 9, 2016 2 hours ago, Young Ed said: Nice truck. From my experience come with an estimate and then double it to account for all the little stuff that comes up. Thanks, that's good advice. I can tell people what they are looking at in over runs in home construction and remodeling but this is new to me. Quote Link to comment Share on other sites More sharing options...
RodFru2u Posted September 9, 2016 Report Share Posted September 9, 2016 Good looking truck, Welcome to the Forum. No idea what it will take to do the swap but if you were in So Cal( LA area ) I could introduce you to a gentleman who has done it. Where in CA are you located ? Quote Link to comment Share on other sites More sharing options...
rhelm1953 Posted September 9, 2016 Report Share Posted September 9, 2016 If the differential is in good shape there is no need to replace it although depending on the gear ratio and your intended use for the truck you might want to. Things you do need to change: New radiator with custom fan shroud New driveshaft Custom fab motor and transmission mounts Custom Fab exhaust system If the truck is not already 12V convert to 12V, even if the truck is 12V you probably want to rewire the entire vehicle upgrade the brakes, minimum a dual master cylinder and front disc brakes Depending on the size of the transmission you may need to modify the floor New throttle linkage and transmission shift linkage Depending on the layout you could have interference with the steering linkage and need to modify/change the steering column and/or steering box. Even if you don't need to replace anything in the steering you may need to rebuild it for safety. If you keep thinking I'm sure you will come up with more, it's a very doable project and helps if you have some welding and fabrication skills. Love the truck and with a V8 and lowered suspension it will make a killer hot rod. I'm not a big fan of "patina" but this truck I would not paint. Quote Link to comment Share on other sites More sharing options...
Strandrunner Posted September 9, 2016 Author Report Share Posted September 9, 2016 6 hours ago, RodFru2u said: Good looking truck, Welcome to the Forum. No idea what it will take to do the swap but if you were in So Cal( LA area ) I could introduce you to a gentleman who has done it. Where in CA are you located ? Hi Rod, thanks for the response and help. I'm in Thousand Oaks Ca. I would appreciate the referral. Quote Link to comment Share on other sites More sharing options...
Strandrunner Posted September 9, 2016 Author Report Share Posted September 9, 2016 28 minutes ago, rhelm1953 said: If the differential is in good shape there is no need to replace it although depending on the gear ratio and your intended use for the truck you might want to. Things you do need to change: New radiator with custom fan shroud New driveshaft Custom fab motor and transmission mounts Custom Fab exhaust system If the truck is not already 12V convert to 12V, even if the truck is 12V you probably want to rewire the entire vehicle upgrade the brakes, minimum a dual master cylinder and front disc brakes Depending on the size of the transmission you may need to modify the floor New throttle linkage and transmission shift linkage Depending on the layout you could have interference with the steering linkage and need to modify/change the steering column and/or steering box. Even if you don't need to replace anything in the steering you may need to rebuild it for safety. If you keep thinking I'm sure you will come up with more, it's a very doable project and helps if you have some welding and fabrication skills. Love the truck and with a V8 and lowered suspension it will make a killer hot rod. I'm not a big fan of "patina" but this truck I would not paint. Thank you rhelm. This is what I was afraid of. Sounds like a lot of cash up front. It runs ok, not exactly a long haul truck but could get me around town. I have to imagine even with a rebuilt engine I'm in it for over 20k right (including labor)? If that is the case I will fall back to replacing the rope seal between the engine and the trans and fixing the hand brake (non functional). Will it be worth it to replace the rope seal or will it still leak like crazy like it is does now. Quote Link to comment Share on other sites More sharing options...
William Davey Posted September 9, 2016 Report Share Posted September 9, 2016 Strandrunner - here's my back of the envelope estimate..Engine freshened/painted/with alternator, carb, water pump, fuel pump, hoses, manifolds either new or rebuilt = $5K; auto trans freshened with lokar shifter and kickdown linkage = $3k; stronger rear axle with more appropriate gearing, with new seals, bearings & brakes = $1K; Fatman independent front suspension (do you really want a screamin fast truck with a beam front axle and leaf springs?) $3K; boxing the frame so all that new horsepower doesn't twist the truck in half, = $500 (I can't weld); new wheels and tires = $1K MINIMUM; miscellaneous stuff like new gauges, new tilt steering wheel, rewire entire truck, dynamat heat & sound insulation, new drive shaft & u-joints, new radiator, plus anything the truck already needs like upholstery/headliner/door cards/ floor mats etc = $3K. Soooo... I think you're jumping off a $15-20K cliff. And this is only IF you don't do any paint/body work! I faced the same decision a few years ago when a rebuilt 392 Hemi became available for only $4,500 near me. I passed on the hemi, and I still enjoy my truck and all the comments it gets when we go places. Quote Link to comment Share on other sites More sharing options...
Strandrunner Posted September 9, 2016 Author Report Share Posted September 9, 2016 11 minutes ago, William Davey said: Strandrunner - here's my back of the envelope estimate..Engine freshened/painted/with alternator, carb, water pump, fuel pump, hoses, manifolds either new or rebuilt = $5K; auto trans freshened with lokar shifter and kickdown linkage = $3k; stronger rear axle with more appropriate gearing, with new seals, bearings & brakes = $1K; Fatman independent front suspension (do you really want a screamin fast truck with a beam front axle and leaf springs?) $3K; boxing the frame so all that new horsepower doesn't twist the truck in half, = $500 (I can't weld); new wheels and tires = $1K MINIMUM; miscellaneous stuff like new gauges, new tilt steering wheel, rewire entire truck, dynamat heat & sound insulation, new drive shaft & u-joints, new radiator, plus anything the truck already needs like upholstery/headliner/door cards/ floor mats etc = $3K. Soooo... I think you're jumping off a $15-20K cliff. And this is only IF you don't do any paint/body work! I faced the same decision a few years ago when a rebuilt 392 Hemi became available for only $4,500 near me. I passed on the hemi, and I still enjoy my truck and all the comments it gets when we go places. Thanks for taking the time to give me the breakdown. That's what I'm afraid of. I would be perfectly happy leaving the tires (new) (1k), the interior in original condition (3k), suspension I can do later (3k). that saves me 7k and puts it at $9,500. which I could handle. But that does not allow for the oh sh_ts! like fabricated motor mounts, disc brakes etc. So here is the big question. Was your estimate based on me doing all the work or was it based on a mechanic doing it? Quote Link to comment Share on other sites More sharing options...
Dave72dt Posted September 10, 2016 Report Share Posted September 10, 2016 those costs looked a lot like you do most of it. and a lot of it you can do yourself.. Fabrication takes time and what you can't do is expensive. I'm going to have somewhere around 8 to 10 K in mine without labor. It's got lots of things going on that are beyond the basics of that kind of swap but I'm doing all the work myself. Without fabrication and welding skills, you'll need to hire that done. You can do a lot of prep work and reassembly work yourself, reducing the amount of hired time to do prep, enabling the pros to the technical stuff right away. Even at 15 or 20 k, it's still cooler than any new truck you can buy and a lot less money. 1 Quote Link to comment Share on other sites More sharing options...
59bisquik Posted September 10, 2016 Report Share Posted September 10, 2016 (edited) I have the stock flatty with the 3 speed and swapped in a 3.73 differential from a 54 Plymouth. As long as you dont wish to do 75+ out on the highway, she does pretty good on the freeways and long hauls. I stick to 60-65 and she cruises along just great and she pulls all the grades with ease. I drove her to Las Vegas last year with no issues. Maybe find an old Borg Warner R10 OD unit (my next project) and swap that in for some highway use or look into to T5 conversion. With a decent running flatty, that would keep you motoring along until you could save up for a V8 swap down the road if still desired after adding some much needed gears. BTW... Shoot that rig with some low gloss clear and preserve that awesome old patina paint job! Edited September 10, 2016 by 59bisquik 1 Quote Link to comment Share on other sites More sharing options...
pflaming Posted September 10, 2016 Report Share Posted September 10, 2016 "BTW... Shoot that rig with some low gloss clear and preserve that awesome old patina paint job!" 59bisquik. I didn't say that but I totally agree. Wow! People are gathering! I've got company! 1 Quote Link to comment Share on other sites More sharing options...
Strandrunner Posted September 10, 2016 Author Report Share Posted September 10, 2016 5 hours ago, 59bisquik said: I have the stock flatty with the 3 speed and swapped in a 3.73 differential from a 54 Plymouth. As long as you dont wish to do 75+ out on the highway, she does pretty good on the freeways and long hauls. I stick to 60-65 and she cruises along just great and she pulls all the grades with ease. I drove her to Las Vegas last year with no issues. Maybe find an old Borg Warner R10 OD unit (my next project) and swap that in for some highway use or look into to T5 conversion. With a decent running flatty, that would keep you motoring along until you could save up for a V8 swap down the road if still desired after adding some much needed gears. BTW... Shoot that rig with some low gloss clear and preserve that awesome old patina paint job! Thank you. That is great advice. I am definitely going down the plan B road since I can't put 20k into it. now. I'll start looking for that 3.73 differential. Thanks again! 1 Quote Link to comment Share on other sites More sharing options...
pflaming Posted September 10, 2016 Report Share Posted September 10, 2016 A local salvage yard has a '97, 3:73 Cherokee with disc brakes for $350. Well he did last week, was saving it for me. You will like this set up. I can drive up to the Sequoia big trees, 6500' and never down shift and an easy 65 on the open road. 1 Quote Link to comment Share on other sites More sharing options...
William Davey Posted September 10, 2016 Report Share Posted September 10, 2016 On 9/9/2016 at 6:43 PM, Strandrunner said: Thanks for taking the time to give me the breakdown. That's what I'm afraid of. I would be perfectly happy leaving the tires (new) (1k), the interior in original condition (3k), suspension I can do later (3k). that saves me 7k and puts it at $9,500. which I could handle. But that does not allow for the oh sh_ts! like fabricated motor mounts, disc brakes etc. So here is the big question. Was your estimate based on me doing all the work or was it based on a mechanic doing it? Strandrunner: my estimates were based on me doing a lot of the work (except welding, engine machining, transmission overhaul). Have you driven your truck as it stands now? There's a kind of charm and personality for the original drive train that can be fun. Also, if you don't replace your front suspension you probably want to rebuild it now with new king pins, bushings, tie rod ends, spring shackle bushings etc. You then will have a fair amount of money in a suspension system that will be thrown away when you convert to IFS /rack & pinion/power steering etc. My truck has stock front suspension in decent shape with new radial tires, but I don't think I'd ever drive it faster than about 60 mph especially in traffic. 1 Quote Link to comment Share on other sites More sharing options...
wayfarer Posted September 12, 2016 Report Share Posted September 12, 2016 Your project has been done too many times to count, but you get to choose the variations of the content. I'll suggest reading through this thread: 1 Quote Link to comment Share on other sites More sharing options...
Merle Coggins Posted September 12, 2016 Report Share Posted September 12, 2016 The good news is that the C-Series trucks had a V8 option, so it shouldn't take as much modification as would be needed on a B-Series, like Dan's truck linked earlier. 1 Quote Link to comment Share on other sites More sharing options...
Strandrunner Posted September 12, 2016 Author Report Share Posted September 12, 2016 Since I have a flathead 6 doesn't that mean I have a B series? Quote Link to comment Share on other sites More sharing options...
Strandrunner Posted September 12, 2016 Author Report Share Posted September 12, 2016 I just found an article saying they continued the 6 in the C series . Thank you for the info. Quote Link to comment Share on other sites More sharing options...
Jeff Balazs Posted September 12, 2016 Report Share Posted September 12, 2016 1 hour ago, Merle Coggins said: The good news is that the C-Series trucks had a V8 option, so it shouldn't take as much modification as would be needed on a B-Series, like Dan's truck linked earlier. I wonder what the bell housing and motor mount situation is like on these C series trucks? Maybe going to a V8 on one of these later trucks is easier than on a B series? Maybe not...... Cool looking truck though. Remember seeing it listed on C/L. Right on......you are in the right place now. Jeff 1 Quote Link to comment Share on other sites More sharing options...
Strandrunner Posted September 12, 2016 Author Report Share Posted September 12, 2016 Good point . No matter what to swap the engines is going to open the Pandora's box of things that have to be swapped. Maybe I can get by with a better drive train for a while. Thanks Quote Link to comment Share on other sites More sharing options...
William Davey Posted September 12, 2016 Report Share Posted September 12, 2016 1 hour ago, Strandrunner said: Since I have a flathead 6 doesn't that mean I have a B series? Strand; my truck is a '55 C-3-B8 -116. That breaks down as C series of truck, 3rd version (there was no 2nd version) B = half ton, 8 = 8 cylinder V-8 engine, 116' wheel base. Your truck would be a C-3-B6 if it's a half-ton. Would be a C-3-C6 if it's a three-quarter ton. You'll find this series of letters on the serial number plate under the hood above the steering column. 1 Quote Link to comment Share on other sites More sharing options...
Strandrunner Posted September 12, 2016 Author Report Share Posted September 12, 2016 Thank you for this. I have been looking all over for this information. Quote Link to comment Share on other sites More sharing options...
59bisquik Posted September 13, 2016 Report Share Posted September 13, 2016 7 hours ago, Jeff Balazs said: I wonder what the bell housing and motor mount situation is like on these C series trucks? Maybe going to a V8 on one of these later trucks is easier than on a B series? Maybe not...... The C series bell housing is not like the B series that bolts to the frame side rails. It sits on a removable cross member that attaches right below the spring shackles. The engine is only mounted in the front by the water pump and attaches to the cross member with a large inverted U bracket. There are no side mounts. I have never seen a stock V8 mounted in a C series. FWIW, If I ever did do a V8 swap, I would try and find an early Hemi to stuff in there! Quote Link to comment Share on other sites More sharing options...
Strandrunner Posted September 13, 2016 Author Report Share Posted September 13, 2016 This is good stuff. Thank you. Going mild for now. Replacing the rope seal to stop the leak. Maybe put in a modern starter as well. Quote Link to comment Share on other sites More sharing options...
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