1972 GMC "the beast" c20

[292farmer]

yes but gm installed a governor in it for longevity issues, they wanted it to last forever. they were used in buses and semi trucks mainly ive seen one used as a genarator, had something like 300,000plus hours! put that into road time at say 1mph = 300,000miles! and it didnt smoke! these motors are a little hard to find but not to hard, the bad part is they dont make replacement parts for them u have to find part motors, or have them custom made, the c-60 we own originally had a 351v6 but a 401v6 got dropped it in. the b-60 mack has an inline 6 gas motor which if i remember is 450ci would love to drop a 450ci inline 6 in my truck but dont think it will fit has like 4 7/16 bore and 5 in stroke and it weighs like 800-900lbs

[292farmer]

got some updates on the mack motor 464ci 170hp @ 2800 370tq @ 1000 sae so believe gross is like 200-225hp 400-450tq

and they were 5 speed transmissions (6if u count reverse) so my bad. but here are some specs, there were a couple overdrive equipped ones and some still had the 1:1 5 gear ratio they just added a gear between the low and second, to spilt the difference so they isnt such a large gear reduction gap like in the sm465 better for towing and hauling i believe was the idea
i just listed some major ones there were like 15different models
np 540 series 6.05 to 7.41 first gear options. 540-gd wide ratio 540 gl close ratio 540 go14 had an overdrive of .82
the np 541 had either a 6.15 ot 7.25 1st gear ratio one wide and one close ratio
clark 264VO had a 6.06 1st and .8 overdrive
spicer 3153c 6:1 1st .79 OD 6853c 5.71 1st .86 OD

i have all the gear ratios if you want them i just didnt feel like typing it all i got this info a couple years ago so if some one sees a mistake, please correct me im open to being corrected, i just try to pass on what ive learned, im not trying to be a know it all. im just fascinated with these old trucks and since i cant own them all i read up as much as i can thanks and enjoy!!

[292farmer]

im trying to get the price on this c20 has 350v8 plus sm465 flatbed with tool boxes. think itd be a cool addition to my collection the cool part is think it used to be used by a concrete company my dad used to work for. oh yeah its a dually rear wheel too!!

[Cw72gmc]

Hey there, Just skimmed through your thread and looked at pictures. When I have the time to read it I will. I just thought I'd say I'm glad to see another 1972 Gmc k20 In Here!

Looks Like Its A Great Start. My Thread is "Jack Lallane". And If you need any help or advice Feel free to ask anytime!

Best of luck with your project

[292farmer]

thank you ill be sure to check your thread out!

[292farmer]

did the wiring in my truck camera died so only got one pic but it shows what was the problem, the wires looked like this in about 8 diffewrent spots where their were any wires left, my reverse light still dont work so im assuming that it needs the switch.


also as some of u know ive been trying to find a second vehicle so i can really work on my truck with out worring about if its gonna be done for drive to work monday lol here are the pics i took of a 1977 trans am 301v8

[292farmer]

well had some free time today and wanted to try an idea of mine so ripped into the front of the truck and took off the grille, bumper, headlite, parklights, and brackets including hood latch. wirebrushed and sanded the radiator support? think thats what its called... then sanded the grille and painted it and i started hand sanding all the headlite buckets im gonna paint those too rust proof them. and i need to straighten the bumper and bumper brackets as it was pretty twisted. also got pic of headlite bucket believed its called before and halfway through sanding to show how shiny they can get

[292farmer]

and the painted grille, it was dark by the time i finished painting the radiator support, so idint get a pic but will get some tomm. and might i add sanding by hand really gives ya cramps!! lol

[Wideopenracing15]

Any updates of the black grille? I'm excited to see what it looks like. I think I might do the same thing with mine.

[292farmer]

hopefully tomm!! i 've been so busy we moved to a new place also had two friends move in to spilt the rent, and found a odd job to make some cash so jumped on that, so keeping my fingers crossed that its about 10 degrees tomm and i fnd time to finsh it, ll post pics as soon as possible.

[Wideopenracing15]

If yours turns out the way I'm thinking it will, I might do the same to mine.

[292farmer]

well im going to take some pics tonite, as i change oil in the car, so they will be up tomm if not late tonite.

[292farmer]

well here are the pics of the black grille in place, and i started sanding the lower half of the truck and painting that black too. while the paint was drying i was changing oil, and repaired the oil pan in my wifes car also did filters and spark plugs took me ten mins to find the plugs are they are under neath two covers and in the top of the head sunk in so needed a 4in extension too, felt like an idiot cuz it took so long lol but i love the way the truck is coming so far.

[292farmer]

spilt wood for my boss, so i loaded my truck up to see how it handled. the empty rear fenderwell height was 35in and full load height was 32-1/2 so only sank 2.5in which i feel wasnt bad at all and it took off fine didnt have to give it any throttle just released clutch and she pulled off smooth (i expected it to stall) and still was pretty smooth accelerating which i was pretty surprised at figured it would be slow as a fat pig. i didnt get a final full load pic as it was getting to dark for the camera..

[Wideopenracing15]

lol I know how you feel on your wifes car. New cars are so confusing. In auto the other day it took me 30 minutes to figure out how to get at the belt tentioner to get that alternator off. That made me feel dumb.

Love the grille man! The paint on theside is awesome too. Just noticed the green radiator support, I like the crativity that you didn't paint it blakc like I did mine. I don't know if this was previously stated but is it a rattle can job? I can't really tell from the finished product just but your masking.

Oh and BTW you didn't even make that truck sweat with that fire wood You don't even want to know how much I've had mine lol
What ever happened to the firebird?

[292farmer]

havent bought it as the owner said needs gaslines i looked underneath and realized it needed a gastank too and the calipers were frozen solid..but the seller is next door to me so maybe later..right now my boss lent me his 2005 gmc2500hd w/6L v8 hehe that and my wifes car is sucking all the spare cash up..yeah ive had a 86k20 we used to load that with oak till the suspension was gone lol and my uncles 69 chevy he uses it to carry over 2000lbs concrete mix everyday. (he owns a construction company)

i did the grille support green so it would make the grille standout and not blend in thank god that worked! lol and i did the headlite buckets and mounts black.

and yes it is rattlecan im a perfectionist so it took me a while and i made it hard to tell it was rattlecan. now im deciding on either making a diamond platefront bumper or going stock style either way its going to be black too! thanks 4 the comments.

[292farmer]

hopefully picking up a used bumper today it has holes for fog/park lites off a 1972 c10 i believe? not sure im gonna put baja lites in it and paint it black.

[292farmer]

well here is a pic of that used bumper i picked up for 40$ and some pics of the truck finally fully painted, and the new bumper being mocked into place and painted.i am really pleased with the final result, i do still have to bolt the bumper but over all im nearly finished cosmetic wise.

[hicktownhotrodder]

hey man cool lookin rig. keep up the good work. it takes real guts to keep to ol' inline

[292farmer]

thank you. i wouldn't trade the six for anything,one of my favorite tricks to show off to the the honda boys is to pull off the valve cover and start adjusting valve lash while the motor is running i've done that in the walmart parking lot before,some guy was trying to impress his buddies saying how old cars and trucks are junk compared to today tech, his buddies were more awed by my adjusting then anything he said some of them thought it was voodoo magic lol

[89muscletruck]

Originally Posted by 292farmer

thank you. i wouldn't trade the six for anything,one of my favorite tricks to show off to the the honda boys is to pull off the valve cover and start adjusting valve lash while the motor is running i've done that in the walmart parking lot before,some guy was trying to impress his buddies saying how old cars and trucks are junk compared to today tech, his buddies were more awed by my adjusting then anything he said some of them thought it was voodoo magic lol

That is awesome. Its always a good feeling to impress or surprise the ricer crowd isnt it?

[292farmer]

lol yeah it is fun, me and my dad used to go out with his 2006 gmc its a crew cab dually longbed pick up thats about 21ft long and 10,000lbs with the duramax, with a couple mods its its so funny when u look in the mirror after taking off from alight and watching them trying to figure out why they cant keep up

[hicktownhotrodder]

yeah theres also alot of that in high school its reall fun to get squrielly coming out of the parking lot and ride the kids eclipse bumper

[292farmer]

yeah i remember those days, actually my high school was as cool as it gets vehiclewise their was one honda del sol two toyotas and an eclipse, the rest were chevy ford and dodge trucks and cars, my cousin had a 56 ford f100 and my buddies had like 6 different 67-72 gmc/chevys couple fords that era and the rest were mid 80 trucks, or like era cars. i had a 77 chevy impala and a 1981 chevy 1/2 ton with a cammed and badly jury rigged multicarb 250 iinline 6. and a 1975 vw beetle.

[hicktownhotrodder]

ha ha ha ha that'd be awesome! i still think its fun for a guy to drive by with subs that sound like they're gonna shake the car apart and lay on the throttle adn shut em up. thats a real system there, 350 cubic inches of american power