478 cu in V6

[squirrel]

Friend got an old bus that was converted to a motorhome...it had the engine swapped a long time ago to a GMC V6, 478 cubic inches, gasoline powered. There was also a 4 stroke diesel version of this engine. 5-1/8" bore. Can't wait to see it with the heads off, he pulled the motor out today and will probably strip it down in the next day or two. A 2bbl carb feeds this thing.

[TheSilverBuick]

Re: 478 cu in V6

I know you own a camera too ;)

[Brian Lohnes]

Re: 478 cu in V6

Something like 250hp and 500 ft/lbs right?

Brian

[squirrel]

Re: 478 cu in V6

yeah, and I left it at home. shucks.

a bit over 200 hp, and gobs of torque. problem is finding a rearend or overdrive trans for a 50 yr old bus so it can go 70 mph

[Brian Lohnes]

Re: 478 cu in V6

Is the redline somewhere in diesel territory?

[Scott Liggett]

Re: 478 cu in V6

Is this anything a kin to the GMC V6 that made it's way into pickups in the 60's?

[squirrel]

Re: 478 cu in V6

yeah, it looks just like a 305.

And half of a 702.

[CTX-SLPR]

Re: 478 cu in V6

I want measurements!!!!! Can you get me crank pin diameter, main diameter, rod length, piston compression height, and deck height? I'm expanding my engine database and I want to turbo one of these after offset grinding the crank and fitting something like BBC rods for less weight.

[squirrel]

Re: 478 cu in V6

I think the rods are 7" long. 3.124" main 2.811 rod journals (huge)

This thing is a torque monster, not a high RPM screamer.

[TC]

Re: 478 cu in V6

I think the rods are 7" long. 3.124" main 2.811 rod journals (huge)

This thing is a torque monster, not a high RPM screamer.

That's all in the eye of the beholder. ;)

[squirrel]

Re: 478 cu in V6

The ports are sized for running at 3000 rpm....good luck making it turn 6000 and make power there

[TC]

Re: 478 cu in V6

The ports are sized for running at 3000 rpm....good luck making it turn 6000 and make power there

Extrude Honing?? :



Just throw a turbo on it. :D

[squirrel]

Re: 478 cu in V6

He pulled a head off it, sent me a couple pics, the pistons are huge...and .040 over...not much wear in the bores, but the head gaskets were a bit iffy. Should clean up nice and be a good motor, hopefully

[jays67]

Re: 478 cu in V6

they are cool engine i almost bought a 65 gmc pick up with one in it
my pops worked at a dealer in the 60's and told me about the diesel swap on them guess they were done at the dealer?

[squirrel]

Re: 478 cu in V6

The pickups got the little 305, not quite the same as the 478....although it looks kind of the same.