my 1988 GMC 7000 dump truck story
 

1988 gmc 7000 bbc air cleaner tag shows 454 7.4L looks like spicer 5 speed tranny with 2 speed rear and full air brakes and air control on rear for trailer.

vin # 1gdm7d1b5jv520621

story is its got bad motor . said it over heated a few times and has not been correct since then . I pulled the fuel tank cap and the gas smells funky and the window reg shows good till 2015 . . so I know she has been sitting for prob 2+ years now inop .

she is low miles 50-60k range from what I was told ( forget to read my self ) but the frame / cab / dump box are in premo condition if you gave it a good wash you could eat off them . frame rails almost all original paint still there .

truck is from the south original and I think it prob had water in the cooling system only ( seen lots of them like this ) and she prob boiled over and or froze the block and cooked its self .

I have a good 454 from a 79 suburban with 60k miles on it and run good on way home with few flat cam lobs . . just need cam and gaskets . was thinking swap this in place of its dead 454 . . . or even find a 8.1 big block with efi and drop in .

what do you think it would be worth in its current state ? keep in mine I am in the heavy rust belt of the north east and clean ones like this are super rare to find . . .

I can buy it for less than the dump box is worth used pull off. so worst case I flip the box and have a free truck .

was planning on making a big boy toy with it . :sumo:

thanks for any input guys and as always have a good day :gmc2:

Re: so i went and looked at this today
 

Nice looking truck.

If the price is right, like it sounds like it is, I would grab it, especially since you have another engine to drop in there.

Keep us posted on it.

Re: so i went and looked at this today
 

well I am in north nj and I cant say I have seen many as clean as you say it is but a truck like that sitting that long with a bad motor I would say 1500. the retail market on these trucks is not that high anymore from what I see. I had a guy with a fully operational on the road truck that he got 2000 for now it wasn't perfect rust free but fully serviced and road legal. grab it cheap sell the box and make a big boy pickup out of it.

Re: so i went and looked at this today
 

so I got the title today on this old girl . . . cost me 1600 bucks but she has 1 clean frame and body and dump box .

just got to wait for the snow/ice to melt off the dirt road to the top of the hill were its parked and then the boss and I can go get it with the BIG tow truck .

Re: so i went and looked at this today
 

Im in to see what you do with this Biggin.

Re: so i went and looked at this today
 

this most likely has a tall deck BBC and your 79 454 is a short deck meaning the accessories will not fit

Re: so i went and looked at this today
 

ya I know.

vin decode shows 6.0 366

but seemed funny I swear I saw 7.4 on air cleaner tag . . . was blowing 20+mph and 10* out the day I walked up the hill to look it over.

if need be I have a line on a 427 tall deck motor currently running .

Re: so i went and looked at this today
 

I keep hearing bout a tall deck 454, but never seen one. I've been to a couple yards that had a billion of these over the years, nothing. 6 bangers, 350s, 366, 427 but no '54s. I haven't found another 8.1 either...guess I got lucky with mine!!!

Re: so i went and looked at this today
 

Great looking truck. Show us some interior shots when you get a chance.

Regarding the motor I've been trying to find out if the crate 502 or 572 are tall deck motors. With the 572 it would need lower compression pistons and a truck minded cam to be worthwhile, but it sure would be nice to be back in to the high torque numbers. I think my duramax spoiled me 😀

-Richard

Re: so i went and looked at this today
 

Believe 502 is standard deck and 572 is tall....

Re: so i went and looked at this today
 

That is good info, thanks.

Re: so i went and looked at this today
 

if I decide to keep it and make a big boy toy out of it . . .

I was planning military 5ton axles that come with air brake . and also the 5ton transfer case as high range is .7xx over drive to help over come the 6.44:1 axle gear combo . plan on a 46-48" tall tire combo also .

just a few ideas kicking around in my head.

Re: so i went and looked at this today
 

got back there today and plowed the road up to the truck so I get it towed out by the end of the week when the road is melted off for the BIG tow truck to get up there .

vin decode and air cleaner tag show 366 engine. . . but air cleaner tag shows 7.4 also . searching internet this seems to have been a common thing .

I got a idea tho . I have a line of a 8.1 big block complete take out . this would be a great repower for it and its from a med duty truck already .

gvw on the tag on the side of the cab door frame 9000k frt / 19000k rear / total 28k gvw truck .

glove box had 2 FULL rpo code sheets in it.

showed :
038 / 6.57 ratio rear
fxv / 149 inch wheel base
gyh / aux rear springs
kra / engine gov 3800

way to many to list up . . .

anyone got a good rpo code brake down list ?

Re: so i went and looked at this today
 

I can take a shot of a list I have and post it later this evening.

-Richard

Re: so i went and looked at this today
 

Sorry, a bit late on this. These are the codes from 1988, best I can tell they used the same codes for years. All of these agreed with what was on my 89.

-Richard

Re: so i went and looked at this today
 

cool man :metal::metal:

anyone know how it governs the engine at the 3800 rpm ?

Re: so i went and looked at this today
 

It had some electronic brain, I'm not sure if it tweaked the timing or did something with the throttle.

-Richard

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if I can find the re-power engine I want this will be gone anyways . . . ha ha ha

Re: so i went and looked at this today
 

few pics I got yesterday

Re: so i went and looked at this today
 

well here was the hill / farm path up to the trucks parking spot this am . . I even went up yesterday and dumped 150lbs of salt down it didn't do hardly squat .

the tow guy backed up to the truck . 1st attempt up hill failed . . but second was a winner .

hooked it / chained it / strapped the steering wheel and away we went .

he did say she has tight steering as most every thing he pulls wanders all over in the back . but my dump was straight as a arrow.

Re: so i went and looked at this today
 

also got to looking at the parts truck next to it .

its a 7000 model also with factory diesel .

I noticed it has a power steering box with 2 extra hose ports that go to a hydro ram that's bolted to the left frame rail / special pitman arm .

would this be something I might wana grab for a price ? incase I want beffyer steering if I go 4x4 conversion with 5 ton military axles ?

Re: so i went and looked at this today
 

If you already have power steering it is pretty beefy. I went and looked at your first post, is that the parts truck right beside it? Does it have a tilt front end? If so that is what I'd be after! And what diesel does it have?

-Richard

Re: so i went and looked at this today
 

yes I have p/s but my thinking was for the 5ton military axle swap if I keep it and make a big boy toy out of it . the extra ram would help turn the 48-53" tires I would run on it . some 5ton trucks in military have a ram on the pass side to help take load off the parts I have noticed .

and yes the other truck has the flip nose option and its a factory diesel that's hade lots of stuff pillaged off it already . the flip nose hood I tilted up to see was super floppy and the truck had a lot more wear / tear than mine . would it be worth a second look and if so what would it be worth for the front nose parts ? I know the rad is gone and a lot of its brackets / mounts .

I don't mind my hood only style that much . I am working on one currently and had to get in the pass side . I unbolted the inner fender and had tons of room inside.

Re: so i went and looked at this today
 

I'm not sure what the tilt hood and core support would bring. I do know that working on my brother's dump truck of that style, climbing up and down all day got really old. We swapped a school bus engine into his dump truck, the bus had the tilt front and the used the same radiator.

I checked the factory service manual and the steering setup that you are describing is called semi-integral and came on the 12,000 pound front axle trucks.

-Richard

Re: so i went and looked at this today
 

tuned in. like where this is going.

Re: so i went and looked at this today
 

GM made a tall deck 427 for the trucks

Re: so i went and looked at this today
 

so if I was to go a big crazy and old school . . . .

would a 6v53 from a gradall grader be a basic bolt in ?

I found one local with engine / trans / rad from said unit with just under 1k hrs on it for 2k cash .

I have always loved the sound of a screemin Detroit and yes I know there NOISEY . I have a 2 stroke atv already so I am use to the sound.

I know the med duty stuff use to get these in them . just not sure if my 88 would be basicly equipped for it tranny wise / bellhousing stuff.

I can fab stuff for mounts and such easy .

Re: so i went and looked at this today
 

It would fit one way or another, but I don't believe any were available from the factory with one. Some of those years got the 4-53 though.

Re: so i went and looked at this today
 

I know I got ideas floating all over in this thread .

a side from the tall deck diffrences why couldn't I just use a 454 I have ? ?

I know the tall decks were to make room for the 4th ring for extra oil control . and a few other things are different.

just hate to buy more crap I don't need / and why not use what I got in stock for years.

Re: so i went and looked at this today
 

Don't see why it wouldn't work. Might have to use the funky water pump with the weird outlet and fan location off a tall deck, but don't see why couldn't use electric fan....

Re: so i went and looked at this today
 

The regular 454 should work fine, I think the main challenge will be the bracket system. Anthing that bolted to the head and something else like the block may no longer fit because the head is farther away. It is doubtful that you could use the water pump off of the tall deck as it has to mate to the intake and block. The tall deck intake will be wider.

Still a good set of 454 brackets and I think you'll be good to go with minor modifications.

-Richard

Re: so i went and looked at this today
 

look what showed up around 11:30 am today . . . . just fits past the lift arms on the shop lift . mirrors folded in for sure .

then after a few hr's of basic stuff the truck sneezed and blew its nose off.

after checking it over the motors is most likely junk . huge NON-coolent rust trails from head /block area on left side . 1 is the whole front face of the engine for the trail .

also tried to roll it over and it got to a point and stuck . . . that was with the battery hooked up. . . with huge pry bar it bound past ... I think few cylinders are rusted up from leak and sitting .

thanks to a local member junkyard hunting he told me a local yard 1hr east of me has a 427 tall deck create engine in a truck for cheep money . . going Tuesday to look at it and other small parts .

Re: so i went and looked at this today
 

the baked to a crisp engine is out after tinkering with it the last few days here and there . today I dropped the manifolds back as 1 unit . then unbolted the starter and bell housing . once held with the hoist ( make sure legs are all the way out HEAVY motor ) I removed the front U-bracket mount and wiggle / jiggled / pryed her from the pins and up-out she come.

also have my eye's on a engine/tranny combo complete take out with everything on it already drop in / hookup and fire. waiting for reply on shipping price back from them .

Re: so i went and looked at this today
 

sub'd

Re: so i went and looked at this today
 

well said screw it and undid few more items and popped tranny out also .

best time now to clean up / reseal / degrease the frame / get all ready to drop back in the hole.

p.s. its great having 2 engine hoists . . . :metal:

Re: so i went and looked at this today
 

Wow, making good progress. Yes these parts are heavy and hard to handle. A second lift is a real blessing.

Re: so i went and looked at this today
 

I hear ya buddy . . . . .

called on other motor/tranny combo they nock off 125 if keep tranny . . . the parts are worth more then that to me . . .

said $1150 shipped to local ( 10min drive ) terminal . drove to lot were they parted it . 125k miles . . .

lookin like this is the better way at this point since I found more carnage today ....... YES MORE DAMAGE ......... the clutch @ 66k miles is on the rivets and scorred both flywheel and pressure plate. :cuss::banghead: what did they do to this thing .

hate to say it but wish I had a way to test the rear end at this point . cause if it was bad I would part it and make a BIG boy toy

Re: so i went and looked at this today
 

Looking at the pictures, you have an Eaton 17201 or 17220 (23,000) rear end. I just changed my ring and pinion on mine from 5.29 to 4.56. My truck has a 4-53T Detroit Diesel which is governed at 2,500. With this change I now have a road speed of 67 MPH. These Eaton's are heavy duty rear ends usually found in larger trucks. I doubt anything a 366 could dish out would do any damage to this rear. The way to tell you have the heavy rear end is the axles are held in with 12 bolts (glove box will show the Eaton 17201 or 17220). Here is a link to my rear end ring and pinion replacement.

The 17220 is a later version with 32 splines, vs the earlier 16 splines, and a slightly different pinion carrier assembly.

http://67-72chevytrucks.com/vboard/s...d.php?t=729084

Re: so i went and looked at this today
 

oh I know I got the 23,000 rear with 2 speed and 6.57 ratio . and has a lot of bolt/studs for the shafts .

I know its prob just fine . . . . but my luck ya never know.

Re: so i went and looked at this today
 

Easy way to know is to pull the lower (bottom center of housing) drain plug. It is magnetic and if anything is afoul it will have parts attached to the magnet. Mine did not have anything on it, however a little fuzz would be normal. Great opportunity to drain and replace the gear grease.