2 ton blazer?

[krechj]

hey everyone i've been lurking around this site for a while now and just recently came upon something that i need help on. for sale by me is a 1978 gmc 2 ton truck with a 366, 5sp trans, and 2 spd rear end. now my friend tells me that the 2spd rear has like a 9.1 ratio or something which would be insane!? my questions are... would i be able to use the 5 spd that came in this truck and would it have the same bolt pattern as a regular sbc cuz ive never heard of a 366? and does anyone know the actual gear ratio of these 2 spd rear ends? im fairly sure that regearing my dana 44 front end to a 9 to something ratio is impossible so i'd have to come up with a solution to that as well. anyhow im just looking for opinions on the feasability of swapping this driveline to my blazer and i've got plenty of time now that its winter and the 2 ton truck is dirt cheap so....

 

[jekbrown]

sounds like a GMC 2.5 ton to me. Axle gears are very low, 6.17 or something like that. No idea what you mean by "2 spd rear end".... axles only have one speed. T-cases / trannys are where different gear ratios come into play. At any rate, these axles aren't nearly as popular as Rockwell 2.5 ton axles are. D44 probably can't be gear-matched to either one. Dunno about engine/trans compatibility, dunno jack about the 366. The rear axle alone isn't gonna work in your rig tho.

j

 

[beater_k20]

more trouble than its worth really. it'd be alot easier to use a 14FF, it will bolt in no problems, no probelms matching gearing, and it will handle whatever tire you can throw at it.

the 366 is more hassle than its worth too.

could very well be a 2 speed rear end though.

Many big trucks came with 2 speed rear ends. There are a set of planetary gears inside the third member that can be ingaged or disengaged to reduce the gear ratio. Yes you can shift it from inside the truck. Most trucks have a switch on the gearshifter.

 

[krechj]

oh i've got a cucv blazer with 14bff already but i got ****ty 373's for gears with a 6" lift and 35's... the ads on craigslist here http://minneapolis.craigslist.org/pts/228347088.html
i keep seeing these 2- 2.5 ton whatever trucks with these 2 spd rear ends and i've never understood what theyre talking about but i do hear about them alot, i'll prolly call the guy tomorrow or somethin and ask him what it is exactly. any idea on if the 366 had tthe same bolt pattern as a regular sbc because i think that 5 spd would be fun

 

[1979jimmy350]

a 366 will have the normal chevy belhousing pattern, a two speed rear would be sweet but not practical in a 4x4, it might make a good tow rig though

 

[jekbrown]

Many big trucks came with 2 speed rear ends. There are a set of planetary gears inside the third member that can be ingaged or disengaged to reduce the gear ratio. Yes you can shift it from inside the truck. Most trucks have a switch on the gearshifter.

cool! learn something new every day! Can that be shifted on the fly?

j

 

[55Willy]

not worth it to swap to.

the 366 is a tall deck truck block that has zero horse power and is built for torque. it's a big block style motor but internaly balanced like a small block is (i think thats right)
the 5 spped would not be "fun" as you call it. it's a hauling truck tranny the gears would be farther apart in ratio then your wheelbase is long,LOL.

If the truck is that clean and runs good why not get it and make it a hauler for the wheeler???

 

[krechj]

hey thanks for explaining i tried searching but couldnt find nothin really! i think it'd be really cool to try, my trucks on its way to being a mostly trail only rig anyhow... i'd really love to throw that rear end in and crawl up ANYTHING but theres no way i can think of to match the front, unless theres planetary geared front ends out there somewhere? i'd like to see what more ppl think about it but i think itd be fun to try i mean i could always use a winter project

 

[bigbluesuburban]

not worth it to swap to.

the 366 is a tall deck truck block that has zero horse power and is built for torque. it's a big block style motor but internaly balanced like a small block is (i think thats right)
the 5 spped would not be "fun" as you call it. it's a hauling truck tranny the gears would be farther apart in ratio then your wheelbase is long,LOL.

If the truck is that clean and runs good why not get it and make it a hauler for the wheeler???

OOOHHHHH... Look at the big brain on Jeremy... LOL

 

[krechj]

u kno i might just pick it up either way and maybe drop a 454 in it or something and make it a hauler. and i figured the 5spd would prolly be fit for much larger trucks, guess i'll have to stick with ony 4 spds haha

 

[55Willy]

funny how I can talk other people through it but if that truck was here ( or like the 54 gmc i found that sounds the same as it but with a inline 6) I would buy it,LOL

[hijack]I maybe snagging a 69 k20 long bed...cheap[/hijack]

 

[beater_k20]

IIRC that rear axle will be about the size of a Rockwell, if not bigger. trying to find an axle with a matching ratio would be tough enough, much less a 2 speed steer axle. in order to knock that gear down enough to make it uable, and get some decent clearance you're going to have to run a tire WAY bigger than the 35-37" tire that's safe on your '44.

 

[diesel4me]

keep looking..

They made 4x4 versions of the C-60 and bigger trucks!..but finding one is difficult,only some telephone and electric,and logging companies bought 90% of them...I'd love to score one!..the 366 isn't a "bad" motor,but its no performance king like a 454--it has a small bore,long stroke,doesn't like to rev,but pulls well at low speeds..it has the "tall deck",so the pistons can have 4 rings instead of the usual 3 on most other chevy's..(some big truck 427's were that way too,on C-60's and busses)..

I have seen one C-60 made into a 4x4 by using a Dana 60 front end,and a custom "ratio box" between the transfer case and front differential,to "match" the gears to the rear end--but only worked in 4WD,since you would only use it when crawling anyway,not on the highway when the rear would be in high range..

The 2 speed axles had a small electric motor like a heater motor to engauge the planetaries while underway...I drove a ramp truck with one,it sounded like it ground a pound of iron off the gears every time I'd shift it!... --but it was nice having a "dual range" when pulling steep hills..too bad they dont make a matching FRONT diff set up that way!..

 

[blazin_blazer]

i'm running a tall deck 427 in my rig and have basically ideled thru stuff that 454's had to use mid throttle to get thru,
the tall deck 427 looks identical as the 366,only way you can tell the 366 from the truck 427, is by the crankshaft casting number. they make adaptors to put the car bbc intakes on it, which is the only thing thats not stock in my engine....
the 454's i'm talking about have been warmed up, some quite a bit, and they have to get heavy on the skinny pedal(3000-4000 rpm's)...while i can follow them at about 1500-2000 rpm's
i have several bbc's and once i found the truck 427 out of a big dump truck, i did a stock rebuild with an aluminum intake and i won't go back to either of my 454's or the car 427 i have, unless it breaks, but we're talking about a motor that could pull a full dump truck while pulling a lowboy trailer with a dozer on it and not even break a sweat, i don't think i'll ever hurt it in my k5

 

[Cornfield creations]

I'd buy it, put a flat-bed on it, or maybe even a roll back and make it my rig hauler. That'd be cool. Kinda tall though, might have to take some springs out of the back pack.

Yeah those rear ends are HUGE. Putting exhaust on those trucks I look at them a lot. They're fun to drive too!

 

[gmc4cw]

cool! learn something new every day! Can that be shifted on the fly?

j

yes. they can be shifted on the fly just like the trans.

It would make a good tow rig.