GMC 478 BIG BLOCK V-6!

[@jeffmurphree2937]

Outstanding!!! Love it when old trucks are brought back to life! Excellent work !!!

[@bobmctavish5012]

These old V6 engines are awesome. I’ve been collecting them for awhile now. Thanks for the video

[@stellingbanjodude]

Got anything you want to sale?

[@bobmctavish5012]

@@stellingbanjodude depends on what you need. Yes I do

[@stellingbanjodude]

@@bobmctavish5012 first , do these have an sae bellhousing or GM style ? I’ve always been fascinated with these things

[@bobmctavish5012]

@@stellingbanjodude GM style I assume. Didn’t know they were different

[@stellingbanjodude]

@@bobmctavish5012 from my understanding there’s a commercial style thats called an sae 1, 2 and a three 3 I believe. Then the auto manufacturers have bellhousings that are specific to them

[@Cam-sm1iz]

Great Video guys! You shift the auxiliary Trans just like the main box. Example, if you are 1 in the main Trans you can shift through all the gears in the auxiliary. Same steps for 2, 3 and so on. A lot of the shifting isn't really necessary just cruising. You can probably leave the auxiliary Trans in the high gear and just shift the main Trans. Hope that helps...

[@jeffhammers5677]

This spring I got my 1970 GMC V6, 401 CI. I's in a schoolbus chassis. Mine, moving for the first time in 6 yes is on a video...."Spartan Mansion motorhome"

[@dw7094]

My grandfather had some dump trucks and cement trucks with the 478 V6. Those were some powerful engines.

[@skipstein744]

Good find. The GMC v6 engines are all. stump pullers, for sure. Onward!

[@Nudnik1]

I had a 1974 7500 478m in a digger derrick CO Edison NYC . Allison trans. Ran great burned a lot of fuel. That's a nice truck hope you restore it.

[@RonnieSmith-ky6vv]

Man that’s awesome. I’m sure when you figure out your Quadplex auxiliary transmission you’ll get the speed out of it that you want. Just guessing I bet it’s got a 5x4 spicer auxiliary. Those 478s are the best V6s GMC ever made, they ain’t fast but they will pull a house off its foundation. Keep us posted on your progress, that rig is too damn cool.

[@TheAnonymous1one]

I love that front end. These older trucks just have such a unique look. The fact that gauges and air pump work is impressive! Is there any updates on it?

[@meccarepair2597]

I haven’t spent any time on the truck. 6 months ago now I hung a windmill with it but no new updates.

[@andyharman3022]

Since you've been on 6066GMCGuy perhaps you know about the spark plug wells problem. Debris falls into the wells around the spark plugs and then when you take out the plugs, the debris falls into the cylinders. Then when the engine is started again, the debris in the cylinder wrecks the engine. Many of these engines were killed this way. On the 478M that I own a large hex nut fell into cylinder 4 and left its imprint on the combustion chamber, breaking the piston skirt in the bargain. So before you pull out the spark plugs, thoroughly vacuum out the spark plug wells and CAREFULLY inspect them for remaining debris. Then proceed with the compression test. Or maybe just pull the heads and then you can inspect the cylinders.

[@meccarepair2597]

I’ve already changed the spark plugs probably a year ago. Used a vacuum and scraped it clean before I took the plugs out

[@paulolson734]

This happened to me when I was a 17 yr old rookie. Had to learn to do a head gasket on that truck. I think the carburetor is a Zenith Stromberg. Company I worked for had several V6s from 351 to 401 to 478 cu in. Couldn't keep motor mounts in the 478s. They also bolted two 351 blocks together to make a 702 cu in V12. Actually worked on one when I was a mechanic at a Ford truck dealership.

[@vicferrari9380]

Wrong on 702 v12 they shared v6 heads pushrod pistons and such but the block was a one piece casting, the cam went full length as did the crank. I've had my eyes open for one I could afford for ever. I drove a 305 powered 65 pickup for many years. That engine had 200,000 somthing miles on it and like said it would tow your house over the steepest mountain.... if you had the time. The latest I've read on the 702 is it was well liked by drivers and got 4 mpg. 😊

[@bradwescoat7460]

Nice truck I've got a 1968 GMC 4000 tilt cab grain truck with a 305 v6 4 speed

[@thomasadams7795]

That 478 has unbelieveable torque. At low rpm, about 1600. The aux trans should have an overdrive gear, all the way to right and up against the dash. If its a 7041 Spicer, 1st is left and up, 2nd is left and back, 3rd (direct) is right and back, 4th (od) is right and up. Should only need 1st off road in rough going. Split gears with heavy load, 2nd, dir, od, then shift main, and downshift aux to 2nd and split again. Shouldn't need 2nd unless loaded, if you get that 478 running right. There is a website, 6066 GMC Guy with tons of info about those v6's. You probably already discovered spare parts are hard to find. Also, when its running, have plenty of gas, cause economical they aren't. Good luck and have fun

[@meccarepair2597]

I’ve used 6066gmcguy more times than I can count. I’m convinced that I have a bent valve I’ve never done a compression test and that’s one of the first things I should have done. I found 2 bent pushrods I can’t remember exactly which, now both on the drive side bank.

[@firefighteruppy9121]

Glad I read this comment... I just bought a 65 yesterday and don't know much about it. Looks like it hasn't run in years with all the dirt, cobwebs and snake skins laying on the engine.

[@patrickmcgoldrick8234]

63 is the last year of the wrap around windshield. Nice truck .

[@billmoody823]

Needs a valve adjustment. Solid lifters. Carb needs a little work and the timing might be off. It has a lot left on the table for sure

[@meccarepair2597]

I’ve adjusted all the valve lash prior to this video, set the timing, and played with the carb I know the carb still isn’t right. I’m convinced at this point I have a bent valve somewhere.

[@phillipgarrow2297]

Those old GMCs with the big V-6s are tough old trucks

[@MisterMikeTexas]

Neat truck, interesting dual stick manual.

[@ianlulham]

I have a 1936 Austin Ruby sitting in store waiting for me to get at and having already recovered a 1956 Fergie TEF 20 diesel tractor, know the satisfaction of embarking on projects such as your truck. I'm sure your having a lot of enjoyment from every little repair/improvement you make on 'her'? She is a beautiful bit of kit mate. I posted a couple of videos of the Fergie (obviously not of the same quality as yours). I think my expletive on one of them says it all. Cheers.

[@meccarepair2597]

Thank you! I haven’t touched the truck in nearly 4 months. Recently moved into my first home and this summer I’ll be using it to trim trees around the house. I’ve also got a couple more grain bins purchased that will be taken down by the truck. I’ll have more video this summer thanks for watching!

[@auaiao9]

There are many interesting things about the old truck and you did a good job getting it up and running again, and you were able to drive it home. You have a good voice and I enjoyed the video.

[@meccarepair2597]

Thank you, I think this is the luckiest I’ll ever get on one of these old trucks. The only problem I’m having now is the front brakes are sticking and I’ve figured it out just need the time.

[@turbo8454]

I have a 478 Magnum in a '68 HM80 dump truck. I haul in the summer with it. Very strong engine.

[@meccarepair2597]

I still haven’t spent time to check the motors compression which should have been the first thing I did. I’m not sure what I’m missing but the motor refuses to make power and top speed is around 25-30 unless going downhill. I’ve checked and rechecked the timing replaced pushrods and replaced spark plugs.

[@turbo8454]

@@meccarepair2597 Don't discount a fuel delivery issue or a plugged exhaust (animal nest)for your lack of power. Also make sure the linkage opens the throttle all the way. Had an International dump truck with a Red diamond 406 that had no power. The mechanical linkage was worn and only opened the throttle half way. My 478 never lacks for power, even fully loaded. The engine is an animal. The auxiliary transmission is probably a three speed or four speed. Might be a pattern on the shift knob, or a plate somewhere in the cab or on the back of the sunvisor. A tag on the auxiliary transmission itself will tell you what it is and ratio info is easily found with a search.

[@bernardmilot4451]

Those Big Block V-6's were designed to run for 500,000 miles with proper maintenance. They're not good on fuel but have the torque of a diesel.

[@Allegronaut]

Looks like a very fun project!

[@MisterMikeTexas]

You need to do the Tarzan yell before swinging into the pond!

[@edwardpate6128]

Those GMC V6's were purpose built heavy duty truck engines.

[@twoeightythreez]

The nissan VG series V6 engines from 1983- 2004 also have the plugs on the intake side, now we know where Nissan got the idea from lol

[@jasonconklin8172]

Always steal USA ideas could b wrong but believe range rover got ihc moter by cube and sound but no ? 250 6 cyl in old yotas, and 5.7 is Chevy on steroids new yota after redesigned

[@MrEngineman69]

Nice looking truck,that 478 engine is a pretty reliable engine

[@jeffcibulka4186]

Congratulations!

[@jackmagnium6115]

13:26 at least it works. for as old as it is. thats badass

[@silveriocastillo3604]

this truck runs like Speedy Gonzales Great 👍

[@mikeskidmore6754]

My Dad's 67 Chevy C-70 Tandem axle truck with a 5&4 Speed Transmissions .. was only 401 Cubic inches..

[@DaveMcLain]

I know where there's one of these sitting right now. Basically the same truck, tandem axle with the crane but it's a 6X6...

[@farmerjbird]

Awesome! What state you in? I shared this to my Facebook carburetor group and also my trucks antique farm and road group! I have a 61 GMC BV 4010 with a 305 V6 and a John Deere No6 corn sheller mounted on it, hope to do a KZbin video on it in a few days!😊

[@meccarepair2597]

In Missouri near KC. I’m embarrassed I haven’t done much with the truck and I’ve never made it run right. My dad has gotten use out of it with small jobs on the farm my mom too even we put up a windmill for her. I’ll try and find your video now.

[@8000RPM.]

Why can't be this lucky?

[@reecewatson5311]

To shift a double Axle, when up shift each gear clutch and pull the double axle knob...

[@matthewweisenburger2095]

Super cool video and uh…..

[@juliogonzo2718]

That thing is awsome. I bet you could find a decent steering wheel out of an old gmc city bus.

[@frontagulus]

Awesome truck, I'd love a big block gas V6 like that. What is the model of truck? What are the rear axles in it? Second transmission will have some combination of over, direct, under, and deep reduction. Use the top three on the road. I'll bet that the carb is the limiting factor on the power

[@hildablanco1591]

If it has bent push rods it has bad oil pressure and needs a rebuild but the truck is a beautiful peace of engineering

[@tedjohnson5958]

V6 tuff mutha.

[@charlesatwell6658]

The 305 V6 in our GMC 4000 makes valvetrain noise just like that. Mechanical lifters.

[@johnsmith7676]

You mean *solid* lifters... as in non-hydraulic. ALL lifters are mechanical, obviously, by very definition.

[@volvobrynk]

We need some updates on tHis thing? Did your Leran to shift the brownie box yet? That such a sweet truck!

[@meccarepair2597]

The truck has so little power I haven’t driven it much on the road. Haven’t spent much time working on it recently bought my first house and I’ve had very little time for much else. I’ll get back to videos soon though!

[@johnsmith7676]

@@meccarepair2597 Get that thing fixed! C'mon... You can do it.

[@bertgrau3934]

The 4 speed aux could be direct drive or over drive the overdrive pattern is: L H 2. 3 direct would have 3 and (4) high reversed

[@meccarepair2597]

Thank you, the motor is week enough that It doesn’t get much over 30-40 mph unless going downhill. I believe I had the timing set wrong and haven’t tried it since I corrected it so I’m hoping it runs a lot better!

[@bertgrau3934]

@@meccarepair2597 If the timing was excessively retarded or advanced it can run very poorly. I rebuilt a Dodge 3.9 V6, has lots of problems with low power, according to my timing light the timing was right on. Unfortunately my vibration damper had slipped and my actual timing was way off. One night I was playing with the timing, and advanced it by 10 degrees. Made a world of difference I had to back off the timing by 4 degrees, but it ran great, and I was getting 18 MPG 88 Dakota, 4X4 5 speed manual transmission. That was actually pretty good for an 88 . Good luck with the old truck

[@meccarepair2597]

@@bertgrau3934 That’s what I’m thinking. Before I reset the timing it would idle and seem to run perfect but with no power. I reset it about a month ago but I wasn’t the one who moved it and I haven’t taken the time to get it out on the road and test it.

[@bertgrau3934]

@@meccarepair2597 What you can do even at low speeds, up shift early then floor the throttle and see if it accelerates faster, as long as it doesn't ping it may be better. Still if you can take it on the road would be a better check. Good luck Sir That was the same with my Dodge, started fast, ran smooth no.power timing was very retarded

[@turbo8454]

@@meccarepair2597 Make sure the throttle is opening all the way. It's mechanical and will wear.

[@joewebb4836]

Truck would look awesome in olive drab.

[@shannonthomsen3951]

Where are you located

[@brantardrey7360]

It looks like a 1960? The carburetor is either a Carter or a Stromberg I haven't seen one of those in a long time

[@Nudnik1]

Stromberg. I rebuilt mine . Vacuum governor under it.

[@chevboy2]

Too Cool!

[@bryantmatthews93]

472 big block v6😊

[@philipanderson3076]

No,64 thur 66 had that kinda winshield and hood.

[@unrealzebra3662]

Post more man haha

[@chrisjarvis4449]

i have a bunch of nos parts came out of maramar navy air station

[@mikeskidmore6754]

I would pump the accelerator pump ..

[@Steelers2841]

That is a 65 my Dad had a 65 a Ford C700 That had a 477 Gas and MT41 Allison Automatic a Rare Gem from a Fire Truck

[@Steelers2841]

You have a 5 and 4 Speed Manual

[@chetblue4146]

Hi, would you consider selling the truck?

[@roberteshaw9520]

Air horn sounds like a snake hiss, it'd be cool if it was even louder.

[@jaredsnook2385]

Hey I just found this video…but I know where this truck came from! I’d love to talk ya about the truck if you had time.

[@meccarepair2597]

Heck ya! Can you dm me?

[@joewebb4836]

Get out the soap bottle to find leaks.

[@johnzuck6163]

Not 66 for sure they had the gmc letters squared off

[@marlborodemoura1377]

Qwantoz hp ??

[@johnkirby6216]

I have a similar truck with the gmc v 6 magnum I bought it a an action sale I got it running my truck has a gravel box that I converted to a grain box i fixed it up the hole truck I use it all the time for haling gran and fertilizer I Loaded it up with 12 1/2 ton of fertilizer it still was able to do 64 mph going down the highway the forth gear on the 4 seed transmission is over drive my truck gets 14 mpg highway if you want to sell that truck I would buy it off you

[@jasonconklin8172]

Yes odd Jimmy 3/4 tons same x factor ran 456 488 gears factory had no clu why got 5 mpg lol In p/u

[@marioncobaretti2280]

Its no running good , its skipping terribly

[@michaelluciano7774]

Kool video bro man!! 😮

[@jeremykissner2281]

I acquired 62gmc grain truck they are fun

[@Snake.br549]

I hope you changed the oil before you did all that

[@meccarepair2597]

Changed the oil once I got it home.

[@xtr3m3fLx]

Unless contaminated with fuel, oil does not go bad from sitting. That's an old wives tale.

[@jaredsnook2385]

I can’t figure out how to message ya on here but check ur Instagram I found you on there

[@meccarepair2597]

I haven’t been able to find your message.