Hi!
Been a real long time since i posted, but the time has come to try to mate a cast iron powerglide to my gmc 270. (Yes, i know th700 etc are better, but who doesnt like a challenge?)
My question: what flexplate can i use? My crankshaft has 6 bolts.
I see that a chevy flexplate from the same vintage (1950’s) can’t be used since it has another boltpattern and the centerhole is to small.
Hamb forum told me that a pontiac v8 flexplate could work, but i tought you guys perhaps know for sure?
Thank you in advance,
Fred
My '57 GMC pickup had a 270 in it. It used a 4 spd. Hydramatic transmission. Perhaps some of that could be made to work with your 'Glide.
I liked that old Hydro!!! It had a 100:1 first gear!!
It had a 100:1 first gear
???
I've been told that 1st gear is used up half-way across the intersection.
Will Willis
I've been told that 1st gear is used up half-way across the intersection.
Will Willis
Quicker than that unless you had a tall rear end gear!!
But it would sure enough launch like a jack rabbit!!!
The old Hydramatics that we rebuilt in the late seventies and early eighties were out of Caddys and Oldsmobiles. I helped my cousin who owned and ran a large transmission repair facility and then moved on to a specialty rebuilder that did mostly racing transmissions.
An old friend who ran a nostalgia gasser used a Hydramatic with an Opel converter that we had the hub replaced in. We left the first gear shift controlled with the governor because you couldn't manually shift the transmission fast enough to keep from "floating the valves". I was told by both my cousin and my boss at the race shop that they were 100 to 1 in first. I never tore down and counted the planetary so I can't say for sure!!
When I drove that old gasser at the strip, it would shift into second just after the back tires crossed the STARTING line and I remember the tach hitting 7,200 rpm on that first shift. You talk about violent!! We replaced the old Oldsmobile rear end with a 9" Ford because it would break the Olds axles regularly and we could use the bigger aftermarket 35 spline Ford axles that weren't available for the Olds.
My old Gimmy pickup was governor shifted from the factory. It couldn't be held in first gear. 2nd, 3rd, and 4th could be controlled with the lever. Even with the modulator valve disabled it would STILL shift out of first immediately after launch. If I floored it, it wouldn't cross a four lane intersection before it was in second gear and with a loaded log trailer behind the truck, it would upshift at ten or twelve mph wide open. The tuck had a 4.10:1 rear gear.
Those old transmissions weighed almost as much as the engines they were bolted to. They were replaced by the JetAway as the years passed. That old slush box wasn't nearly as good, but it weighed almost as much!! They were replaced by the aluminum cased Turbo 400 about the time that the aluminum Power Glide replaced the cast iron version.