We recently bought a GMC 7000 off of Ebay and it has a worn out 366 in and we're tossing around the idea of either rebuilding this motor or finding a rebuildable 427. I'd like to slip a small diesel in it's place but we don't want to spend 20 grand on a 2 grand truck. I'll post a pic of the truck it came from a junkyard in WV and we had it trucked back here maybe one of you might even recognize this truck. The motor in it is a 366 GM Target motor so at one time someone must have replaced it. The truck has been sitting for a couple years so we replaced the carb, plugs, wires, etc. I'm thinking possibly pulling the heads or the whole thing and tossing in a 427. I had a similar truck years ago with a 427 that ran great, but I'd like to give this motor a chance. I have spent some time doing some research via discussion forums, Hot Rodding, Truck Pulling, etc. and talked to some folks around here and some praise the 366 and others claim it to be a "boat anchor". I'm just kinda looking for some feedback from some real life folks who might of ran these motors in trucks and would appreciate any tips or advice.
Drove a new GMC 366/4bbl/dual exhaust/5-speed 26' box truck back in the late 70's. Was fun-would easily 'take' a few cars off a light. On e-way no problem getting up to 70 then it would back down to 65 (governor). Most of the time it was lightly loaded. Ran way stronger than similar 90's Ford 370/2bbl/5-speed.
i have a 366 in a '79 C65. the truck has definitly been worked throughout it's life. they're gauges that don't work among other things. as far as the engine it is very suprising to me. definitly not a powerhouse but it does deliver the goods. i have overloaded it a time or two and the truck has made it up every mountain i have asked it to. maybe not at daytona speeds but it gets there. i plan on working on updating the truck over the winter. for the money it has been worth it. i can park the truck a few weeks then start it and run when i need it. when the engine goes i wil replace it with a crate 366. just don't see how a 427 would be that much better. it would be great to be able to drop a small diesel in it but haven't heard too much good about diesels from that era that would bolt in. it would also effect the gearing. much easier to stay with the gasser. good luck,
Here it is
Well I had one with a 427 and the only difference I see is a little more HP and torque. I finally got this thing running right yesterday and I'm going to give it a chance. I found a decent old 427 tall deck some guy was going to build a stroker motor out of and changed his mind. I figure I'll tear it down and rebuild it and have it for a standby motor. This truck and the one I before like it have air brakes and air system which will enable me to put an air release tailgate, air operated hoist, and maybe an air PTO shifter. The body is a J&J Body out of Somerset Pa. and the hoist and PTO levers are on the outside next to the tailgate handle, it all looks factory. The only problem with the bed is the tailgate with some rot on the dirt shedders. As far as the diesels go I think the only diesel they put in these trucks were a Detroit 8.2, they say that there's not enough hood clearance for a 3208 unless you go with a Topkick hood. I was reading some interesting stuff on another discussion forum about a blower or even a turbo on a 366. Anyhow the price was right compared to the junk I seen around here and to me it was worth the time and travel putting a new life in this old truck.
I have this motor in my dump truck, an 85 GMC 7000 5+2 hydraulic brakes 23160 GVW. With the split rear end this thing pulls pretty strong. I've heard that these engines are bulletproof and i believe it. Ive wound the snot out of mine pulling heavy loads up big hills, and although i was barely moving at the top, it just took it. Mine has low miles but it doesnt use any oil or make any lifter clatter. definetly a good engine
The 366 was a good motor, lots of low end torque and they are not near as bad as a 370 Ford on fuel consumption. I always found their fuel and ignition systems less tempermental than a Ford. Instead of an overhaul you might look into a crate engine from a Chev or GMC dealer. Prices are not too bad and you get a decent warranty. I'd stay a long ways away from a 8.2L diesel, one of the better boat anchors built by GM. Stay away from the 3208 Cat as well. You might look at a 3100 series Cat instead. It would take some modification, but would be a good engine for this size rig. Good Luck!
Thats a nice looking GMC amscontr.The big block chevys are good engines.I've ran them in everything from chevelles,novas,pickups, & c-70 trucks.Talking about old trucks & chevy engines,I have an old 1966 chevy c-60 that had a in line 292 engine from the factory.The truck has a low geared 2 speed axil & 4 speed tranny.We put a 350 small block in it after the 292 wore out.The truck pulls great with the small block & low gears in the back.I would dang near put it up against a big block truck.Good luck with the GMC project.
366 is tough little engine. BUT!! the one thing you don't want to do is rev the motor without a load on it. You can actually sit and watch the block swell and contract as you rev it. almost a twin to the 396
Thanks, I was ready to give up on the motor until I got the motor running right (I hope?), the truck has been sitting for a couple years and I was told most likely it was a stuck valve. I switched carbs, tuned it up and changed fuel filter and it seems to be running and starting good now. Someone was telling me on another forum about a Detroit 4-53t that came in some of these medium duty trucks. That might make an intersting switch down the road if I decdide to get creative?? Who knows for now the 366 will get it's chance. The engine says "Target Motor" on it I guess it's not OEM? It's defineatly going be less of a headache then the 1988 Ford F350 dump we have with a 460/7.5 electronic nightmare!
that's what I hear about them 8.2's, I had a seires 50 Detroit in a '94 Freightliner FL 106 that had plenty of power it was just heavy on the front end and would do a nose drive in soft dirt. A smaller diesel with a jake brake and 13 spd. would be the ultimate in a medium duty dump, but I'm sure it would be a "PITA" with maint. etc.
366 engine As stated, if you have to replace the engine, I would go with a crate engine. Unless you are able to do it yourself, you will save money with the crate engine and you will have a warranty. I have been through these engine swaps and you can get into a bunch of work and money and in the long run it isnt worth it. Most of the time, you can buy a diesel truck, for what you would have in a replacemnt engineTo change engines, you have to worry about tranny and rear end ratios, being correct. From an old GM53 series mechanic, say away from them on a swap, its possible, but its a OK engine, if its already installed, then all you have to do is maintain it As far as the tailgate, there are lots of good used tailgates, in the salvage yards. I have bought a new one from the factory for around $500 (for a 16ft bed and high tailgate) I have built them myself, its not that much trouble, if you know how to weld Cut out the rust and replace the bad metal with new. Good Luck, and keep us posted
Hi, I have a 1980 gmc 7000 with the 4-53 turbo, great truck and the little detriot really makes it. It's pretty quiet (for a detroit) because of the turbo. Pretty good on fuel also. The only thing I don't like is the hydraulic brakes, I just had to put a new hydrovac unit and all new brakes lines. Make sure your brake lines are in good shape because if one line lets go, you have NO brakes. Mine has the single line system, not sure what you hve. Good luck with the truck! Dave
Thanks, This truck has air brakes, one major reason for buying it. With the air system I can add an air operated tailgate, hoist controls and maybe a air shift PTO. Plus if I decide to pull a trailer I can run air to the rear for trailer brakes. Right now it's a toss up as far as switching to a diesel with fuel prices and fuel taxes. I found a pretty good deal on a 427 tall deck that I'm pretty sure I'll buy and go thru it and keep as a spare/backup. I have been doing some research on those 4-53's and most info I have seen is favorable.
I have a 87 GMC 7000 parts truck for sale I live in north AL and I am probally a long way from you but i have a 87 disc brake 366 engine parts truck that i just bought.The 366 runs and seems good i would sell the complete truck for $650 firm.
4-53's were good little engines, but even with the turbo I always felt they were underpowered. The ones I drove were at any rate. They were also very noisy, an unwanted side effect of the 53 series. Not much on torque either, really rather built for constant high RPM situations. The 427 is probably a better solution, next to a crate engine. Good Luck!
Crete / Rebuild amscont: First of all let me say I HATE 2 stroke Detroit's for highway application! Second I have NO respect for the 3208 Cat unless it's used as a boat anchor! I know nothing of the bolt in exchange diesels for this application! I'm not sure which highway diesels will fit in your cab, with out Jessey James and the last Monster Garage Crew installing it! I dislike gas engines in commercial applications, but I did start out there with 3 gas hog monsters from the Ford (better idea?) Family! Rebuilding your 366 will be around $2K. Then you'll have a rebuilt 366, and in machine work alone $K. Then you'll have to put her back together! and reinstall her, and then get her running again! Think of all the mistakes and specialty tools needed to reassemble this engine! Ring compressors, valve spring compressors, torque wrenches, engine stand, ring file, feeler gages, compression tester, and countless trips to the parts store because you'll always forget something, or break something! With the Crate Engine, You'll have to transplant some of the mounting brackets, and maybe your carb! Bolt on your belhousing, add the pilot bearing, and the clutch, Trany and Voilà INSTALL in truck! NOTICE If your bell has mounts that hold the running gear without a cross member, Remove the engine only! No need to remove the whole unit! This will save you about an hour in reconnecting the engine! Where the red circles are is where the frame mounts attach to the belhousing making a cross member useless! If there is NO cross member then these mounts hold up the trany!
it's good to see this thread still going. these are good workhorses in the right application. great to hear everyone idea's and experiances.
From what I have heard, GM quit making any more 427 Tall Deck replacement engines, but are still selling the 366. I am always of the idea that if I can put a bigger engine in it without changing any major parts along the way, I go for it. I like the idea of dropping a 427 in it. I think that is exactly the way I would go. It should cost about the same and you get more for the money with the 427
my c65 with the 366 hasn't had a gauge work in it since i have owned it. this winter it is getting some much needed maintenance to bring things back up to working again. i have also had the occasional short that keeps it from running. the wiring has been rigged beyond recognition at this point so i guess it will be a new harness and start over from scratch. has anyone done this before or know of a good parts source? thanks,
Howdy Neighbor, I am here in Gray and used to have a couple C65s. I put power steering on the 1978 and have a manual steering gear box with less than 50k if you need it, probably have a ps cy also. Send me a email if you can use them! Thanks Steve
I just found a 427 truck motor for $250.00 up in Memphis Mo.
Motor pic motor w/everything except flywheel and harmonic balancer
Nice find. How much do you think it will cost to get it rebuilt? The are still out there, but seem to be getting harder to find. There is a dump truck for sale in KC that has a blown up 366, and they want 2100 for it. it is an old Ryder truck that they put a dump bed on. I was looking for a 427 to go in it, and couldn't find one. Where did you look to find yours?
Craigslist, it seems there are plenty of 366 motors around. I vave been searching for several weeks finding mostly junk for $400 plus and then I came across this one. First thing I'm going to is take it to a auto machine shop and have it checked out before I have to sink a bunch of money into it. Supposedly it came out of a wrecked truck w/low miles?? If everything checks out ok then I'll probably re-ring it, have the heads re-done, timing chain, bearings etc. Most rebuild kits I have seen were in the $1500.00 range and I have seen 427 truck crate motors going for $1600.
I don't know about a "transformed" Ryder truck. This one was a factory tractor with air brakes and it has a double frame. I think the extra frame was installed with the dump bed, which is a J&J Body from Somerset Pa. the body is in good shape considering the age of the truck. It needs a tailgate, the one on it is pretty rusted and bent up. I have seen a couple flatbeds in your area from $1500 to $2300 in decent shape all with 366 motors. I have seached on the net from coast to coast and border to border for a decent 427 and just got lucky. Like I said before I have seen junk in the $400-$600 range. My goal is to utilize the air system for air shift PTO, air operated pump and tailgate and maybe an air brake tag trailer. I had one before with a 427 and a 13 spd with air brakes it would haul 10 ton plus my skid loader without any problem.
I wish my rig had air brakes some of the time, except for it not requiring a cdl, it stops halfway decent, but air pto and tailgate is something i would install for sure.
Yeah I have had my share of problems with Hydraulic, Vacuum, types of brakes. Now if I could put a Jake Brake on it????
This is my old girl after a fresh coat of paint. It turned out halfway decent for my first paint job, using $30 a gallon tractor supply paint.
That's a good looking truck. I just found a pair of buckets seats w/console for mine. Thye came out of a newer Chevy pickup and are like brand new and are a matching color. The one I got the PTO and Hoist controls are on the outside of the cab next to the tailgate release. My guess is that it was installed that way from the factory because the control have grease fittings and the fabrication is perfect, plus the hydraulic hose going to the cylinder is a quick connect. So the bed can be easily removed and a fifth wheel mounted, I guess.
Hey if you guys are looking for more power out of the 366 motors pick up a jegs or summit racing catalogue! The 366 blocks are tall deck castings of the same big block chevy used in cars and pick ups. This means some of the performance parts designed for cars will bolt right on. The intake manifolds are different because of the tall deck but you can buy a special spacer ($125) that will let you bolt on any performance intake. This will also let you use a good 4 barrel carb. The stock intake or an aftermarket one can easily be milled down to allow the use of a more performance oriented distributer. You can also swap out cams with a little more performance oriented version. You could even toss the stock exhaust manifolds and slap some headers in there Now im not saying bolting on random parts is going to make it do wheelies but a few hundred dollars of well chosen modifications might just bring your performance levels up to acceptable standards.
I owned a 97 GMC 6500 about 4 years ago. I purchased the truck from a dealer in Tennessee. The truck was a Ryder truck with a dump body and fresh paint installed, looked great! After I had it delivered to me I started to use the truck. Truck had fluid brakes and a 366 motor and Allison transmission. The truck couldn't pull my skid steer and trailer and definitely couldn't haul any more than a few tons, I mean it would literally stop on hills when loaded. I had it all tuned up the best I could, new plugs,wires, distributor cap etc and truck ran great just way underpowered. I was stuck with a truck I couldn't use so I decided to try and fix the problem and had a 502 create motor installed. I spent more money on that truck, way more than what it was worth. After the new motor was in the truck the truck was better but still couldn't move a full load and was under powered. I decided to sell the truck off, for a big loss, buy a real dump truck, bought a 89 Mack that I still use today. About a year later I was at my local GMC dealer I see my old GMC truck there getting work done on it. I ask what they were doing on it and they tell that the motor went and they had to put a new motor in the truck. The new owner drove that truck with the second new motor in it and the transmission went! This truck that was only worth maybe $15,000 on its best day had about $25,000 put into it by me and the guy that owned after me. I would guess that after the truck left the dealer in Tennessee the truck had close to $40,000 spent on it and for what? I will never go down that road again, should of bought a real truck to begin with, much smarter now. I am not saying that you can't get your monies worth out this truck but watch how much you put into it. You could be better off putting money into a truck that will do what you want it to do from the start.
Anyone here ever tried to pull start a dump truck? I have one that I have to move this weekend that hasn't been started in over 3 years. I put three new batteries on it, cleaned all the connections, rebuilt the starter and still the same result...it turns over like the batteries are nearly dead. I even ran a pair of 00 gauge cables directly from the batteries to the starter...same results. I'm considering towing or pulling it to start it, but have never done this with a truck this big. Anyone here ever done it? If so, do you have any advice?
Is it gas or diesel? Carburated or fuel injected? Electronic ignition? What motor does it have? Does it turn over with the starter at all?
A Mack is defineatley the way to go. As far as buying "converted" Ryder or U-Haul truck that explains it. It's like putting a dump body on a million mile"Fleetliner" and expecting to preform like a Mack or Western Star. When I started this post I was wanting some feedback from people other then the locals around here who run them motors. It seems the 366 might be a tank motor that's a little under powered but it can take a hell of a lot of abuse. I got a 427 in the garage that I'm getting prep'd for replacement when this motor goes. I have tossed the idea of a small diesel this or that. Now if I had to make a living with this truck that would be different, it's just a truck to have around to use for when I'm laid off or whatever. Making a living with a single axle or any dump truck around here is pretty tough. I don't know how many people I have seen lose their newer trucks and the folks with the older ones are still running. What kind of Mack do you have and how is it spec'd out? Was it a factory dump truck or a converted road tractor?
starting As stated, there is alot of info you are not providing us. gas/diesel/air brakes/year model/etc, kind of tranny I would see if you can turn the engine over with a pull bar, or take the starter off and use a pry bar to turn the flywheel. It sounds like something is preventing the engine to turn, could be 1.stuck engine/seized rings 2.water on top of the piston (head gasket, cracked head/block, etc) 3.unburnt fuel on top of piston, locking it up (mostly a diesel problem) 4.is the tranny/clutch stuck in gear causing you to try to turn the rears when starting I have pulled dump trucks to start, be sure to have a good driver in the dump truck, so he doesnt rear in the puller truck. I almost bought a dump truck a few months ago. It was a 88 Ford L9000 tandem, L10 Cummins diesel, 155,000 miles. It had been sitting about 3 years, tried to jump it and no luck, I ended up pulling it and did get it started, but if you cut it off it wouldnt turn over and Im loosing water. I didnt buy the truck, but it was a cracked head, letting water get on top off the piston. If its a diesel, air brakes, you have to charge the air system and make sure you have the fuel shutoff valve it the correct position (not all engines have this) mostly Cummins. Keep us posted, good luck
amscontr, My Mack has 38,000 rears and 18 fronts, em6 motor and 7 speed, here is a photo:
The brakes are going to be your hard part for pull starting an engine. If you can't pressurized them to release them, then you are stuck. If it is a diesel, which I am guessing it is with 3 batteries, then you might want to pull the injectors and spin the engine over and see what blows out. If it is hydrolocking, you will know when you do that. After you do that and put the injectors back in, and if you can get it to turn over, shoot some ether in it while cranking. But before you do that, check your fuel filters and all that to make sure you are getting fuel.
I have a 1984 GMC 7000 since new 5/2 speed tranny, 366 gasser, hydraulic brakes, 28,000 GVWR & 18' flat bed. Had a 1975 C-5000 Chevy before that. I have been looking at the same dash and cab for 34 years. Use to pull a Lull telehandler on trailer and the truck loaded which was just about 60,000 pounds. Still going strong with no problems. Long Island is fairly flat except for a few locations. Not a rock it by any means but I get their and if I use all the gears it is fine. Emission preheat tubes rotted out few years ago. Engine still runs good. Now it is so old it doesn't even have to have emission testing any more Truck weighs about 10,000 empty. I hope they bury me in it. Still has original exhaust on it. I think I will get it repainted for the second time soon. I have a new hood as the original rusted on the sides but I just patched it up. This time I'll drop on the new hood. It has been a great truck. No regrets on the 366 I think just the bore is different on the 427.
sounds like the cylinders are galled from some one trying to start it over and over and over. when the engine doesnt start you dont get any lubrication and the rings just grind away at the cyls till they just drag something fierce. i worked on a new 502 that a guy thought he could install himself he got it put in but his wiring was not up to snuff, so when he tried to start it , no start. but insted of seeking help he just kept on cranking and cranking till about two months later he brought it to my shop. well it goes without saying the pistons, rings , cylinder walls were done. pull starting might just tear it all up. good luck!
Theres a guy around here that has one with an 8.1L vortech swapped in from a wrecked 3/4 ton suburban seems to work really well. His main logic was to get around CARB smog rules with the diesels and have something that he can use to haul local that can set for weeks and still fire up and do work. Its no modern turbo diesel but it does work well. All and all i think hes got less than $5000 in it including the price of the barn stored immaculate truck.
I have a 1988 gmc c6000 366 motor 5 speed transmission. Wonder how hard and expensive to put an Allison automatic transmission in this old truck. It's an old uhaul truck and have not found a buyer and a stick won't work with my legs. Any ideas and thought appreciated.
All the older GM's used the same bell housing pattern, all you will need is a trans flexplate and mounts to change it over, driveshaft shortening and a parking brake mod would end up next, Most of the later Uhauls had automatics.
Ive got a 1985 7000 with the 366. When i bought it it had a crate engine installed & was over carbed. I Installed a smaller 600 cfm holley & it helped the running a good bit. But something still wasnt right. Turns out the advance mechanisms in the distributor were frozen.....what a difference that made when repaired. Great strong truck, not fast, but strong.