1959 gmc 450

[94cummins12v]

Well I know the title and I'd tage in the glove box say 1959 I'd just like to figure out what engine the damn thing has in ita ran a new 1/4" fuel line from the fuel pump to one of the saddle tanks and put an inline filter in fires right up untill the filter runs dry its almost like the filter isn't filling fast enough for what its burning wonder if I should do a new draw straw

[94cummins12v]

Well I dug a little deeper truck does have a 302 inline six in it

[94cummins12v]

So according to the vin and I'd rage its a 1959 GMC 455 v with a 302 I6, started pulling wheels and getting tires mounted it came with 9.00-20 all around and I'm gunna run 10.00-20 in the rear and 9.00-20 in the front

[94cummins12v]

Curiosity does anyone know what transmission came in these trucks its a 5 speed or a 4 speed with granny low I'm wanting to take the 302 I6 out and throw a 350 or SBC 400 in it

[lv2tri2]

Taking that motor out would be shame, IMHO

[lv2tri2]

sorry about the 2nd entry

[OrrieG]

Look at the link in my signature. Scroll down to the year index tab, choose year then look for the tranny section. Pretty sure 4 speed was all there was, with two speed rear end to split the gearing for heavy loads.

[94cummins12v]

The only reason I'm wanting to take it out is because its blown and SBC are Easyer to come across

[_Ogre]

found a 59 450 brochure on ebay
possibley: 5 speed dirrect or 5 speed od with 2 speed rearend; or 6 speed with single speed rearend

[_Ogre]

your big truck needs a biggg gmc motor: i vote a gmc 702 twin six

[OrrieG]

A couple of months ago I went to one of the wrecking yards and they had one sitting in the parking lot. Looks like it may have come off of an irrigation pump, they were sold for that use (like lots of early Hemi's). Top rpm is like 2500, but they have a ton of torque and will run all day. I will post more pics in a separate thread.

[Highsider]

I knew nothing about the 702 Twin-Six existing.
Is it a 12-cylinder?

[94cummins12v]

The truck is defiantly in fact either a 5 speed or a 4 speed plus overdrive. The reason I'm asking is what itbwould take to bolt up to a SBC 350 or 400 or do I just say screw it and throw a sm465 4speed in its place when I do the SBC conversion

[_Ogre]

unless you can post/google trans numbers
once you have it out rotate the front shaft 10 times and count the tail shaft rotations to see if it's 5 spd direct or 5 spd od
most gmc/chevy transmissions of that period had the 4 bolt pattern to any bell housing

does the truck have a 2 speed rearend?
i had a 56 chevy school bus/camper with a 454 truck motor, 4 speed granny trans and 2 speed rearend
the rearend was vacuum operated as was the little gearbox behind the speedo cluster for shifting the speedo
it would cruise 80 all day and got 9 mpg, not bad for the boat it was

[94cummins12v]

It does have a 2 speed rear end it has an electric control box on it to shift from high to low

[_Ogre]

Originally Posted by 94cummins12v

It does have a 2 speed rear end it has an electric control box on it to shift from high to low

those new fangled electronics for 59

[1project2many]

Somebody spent some money on this truck when it was new! The vintage racecar / land speed guys love getting those old 302's. High torque when new and could make surprising levels of power in the right hands.
http://www.jalopyjournal.com/forum/t...mc-302.586167/

GMC's engineers were usually smart enough to build the truck to fit the engine so keep in mind the 302's stock numbers were 160 hp @3800 and 268 ft-lbs @1600. A 350 would make more power and torque but it might end up spending much time well below its efficiency range without a cam change. There are some really good low end cams out there. The HT383 cam is great for roller engines and is cheap, too. Crane sells a flat tappet cam for "brute low end torque" that's also available under a GM part number.

Ya know, I've just gotta ask with that username, why not swap to diesel? A SBC would be a practical but "Ho-hum" swap but a 4BT would provide plenty of power and torque in the same RPM range as that old Jimmy. A 6-71 would out pull anything SBC that doesn't have forced induction.

[94cummins12v]

I won't do a Cummins conversion in anything ever again I did a twin turbo Cummins 12v in a 96 f350 crew cab long bed and got it featured in a magazine. This dump truck I won't invest that type of money with all the pin heads in this country driving up 4bt and 6bt prices

[66Submarine]

Originally Posted by 94cummins12v

I won't do a Cummins conversion in anything ever again I did a twin turbo Cummins 12v in a 96 f350 crew cab long bed and got it featured in a magazine. This dump truck I won't invest that type of money with all the pin heads in this country driving up 4bt and 6bt prices

LOL!

What about a 454? Those seem to be available cheap these days with the diesel/LS craze. I just picked up a motorhome for $700 with one that runs like a swiss watch to go into one of my trucks.

I think most of the 5 speed HD stuff uses an SAE bellhousing, so you'd need to get one off another HD truck with the right pattern (AFAIK).

I'll also second that the old 2-stroke stuff is neat to see.

[94cummins12v]

I'd consider a 454 if I could get one for a deal I can find late 70s early 80s 3/4 ton all day long for a grand keep the engine and part the rest out