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1965 gmc v8 swap help

7K views 17 replies 5 participants last post by  Old Truck Man 
#1 · (Edited)
Hey guys! I have a 1965 gmc c10 with a 292ci 4 speed, and I have a built 350 for it. I want to swap it in there, anybody have any advice on which motor mounts I need? and rear end? or bell housing help? thanks guys! Posting pictures soon!
 

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#4 ·
Been there done that

Ive actually did this swap. The 292 flywheel will not fit a V8 the attaching bolts are larger diameter. The passenger side frame bracket is different on the 292. So you need a V8 flywheel. A frame bracket from a 63 thru 66 truck. The 230 &250 six & V8 brackets are the same. That rubber engine mount will bolt to a V8 block. you need a V8 clutch pivot ball. of course the exhaust. The throttle linkage will need some tweaking also. your present bell housing & starter will still be used and the clutch disk and pressure plate. The 292 radiator is large enough you will need a V8 fan shroud and the upper pipe for the top radiator connection. you may have to lengthen the alternator wiring harness. and the 292 alternator has a bit longer pulley to allow the fan belt to alighn. you likely will need a shorter pulley.
 
#5 ·
You will also need to revamp the fuel line a V8 fuel pump is farther foreward. And get rid of that clear plastic fuel filter. That's a fire waiting to happen. Ideally you shouldn't have any rubber line under pressure. The factory ran a solid steel line from the fuel pump to the carb. and a sintered bronze filter in the carb for a good reason. I like to place a steel inline filter some place between the fuel tank and fuel pump. I like the GMC,s better than the chevy. I like the rear leaf springs. and the grills are real chrome not polished aluminum. and I like the little round speedometer. and the way the wiring harness plugs into the back of the dash.
 
#6 ·
Thanks for the awesome advice! So far this is what your saying :
-350 v8 flywheel
-find frame brackets for a 230 or 250 or v8 of a 1963-66 truck
-v8 clutch pivot ball ( any advice on a good quality one?)
-exhaust
-tweak throttle linkage
-bellhousing/clutch disc/pressure plate/starter all re used correct?
-fuel lines revamp
-some alternator tweaking ( prob will just use a 350 alternator)

All of it seems fairly easy to do. My 350 is fresh and broken in. The only other questions I guess I have are what rear end? I'm not entirely sure if my rear end is stock or not ? and if so can I just upgrade the gears? I know its a 10 bolt, and for sure would need a bigger drive shaft. Or am I better off pulling the rear end and shaft and finding a drive train out of something else? Any good options?
Thanks again for all your help!
 
#7 ·
On the rear axle will be a series of numbers/letters on top right rear axle tube, you may have to reveal those with sand paper lightly, get those to id your axle before you decide to pull it...we will decode it to find out exactly what you have.
 
#9 ·
Dana 44?

Ok on the rear end you likely have a dana 44. The best way to find the gear ratio is pull the rear cover and count the teeth. My 66 GMC 1/2 with a factory SM 420 trans. The Spider gears went bad. I took it apart and was surprised to find it has 336 rear gears. Took a spare rearend apart to cannibalize the spider gears and that one has 308 gears. I was expecting to find 390,s or 410,s. Now you can swap in a 73 and newer rear end and get just about any ratio desired. And swap the entire front crossmember and suspension and get front disk brakes and 5 lug wheel pattern on your truck.
 
#13 ·
Ok on the rear end you likely have a dana 44. The best way to find the gear ratio is pull the rear cover and count the teeth. My 66 GMC 1/2 with a factory SM 420 trans. The Spider gears went bad. I took it apart and was surprised to find it has 336 rear gears. Took a spare rearend apart to cannibalize the spider gears and that one has 308 gears. I was expecting to find 390,s or 410,s. Now you can swap in a 73 and newer rear end and get just about any ratio desired. And swap the entire front crossmember and suspension and get front disk brakes and 5 lug wheel pattern on your truck.



I still can't seem to locate the numbers on the rear end?
 
#12 ·
heres some pics guys
The numbers will be on that side kind of toward the rear top....you have to reveal them with sand paper, they are stamped in the steel..
 
#16 ·
Its possible you will not find any numbers, on the rear end housing. GMC,s are different from chevys. they have rear leaf springs. and pressed on axle bearings that hold the axles in the housing. Every 1/2 ton GMC I own came from the factory with DANA 44 rear end. and at present I own 6 of them. Ive yet to see a 60 thru 66 GMC with the VIN number stamped on the frame. It wouldn't surprise me if there aint any numbers on the rear end.
 
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