When I was doing the off-frame rebuild of my '65 442, I bought a 455 motor from a 1976 GMC motorhome and rebuilt it. I never could really find much in specs for those motors. Does anyone happen to know what hp, ft. lbs. torque, etc. they had...or where I could get info on them? They must have been a 9+ compression motors, as mine didn't have the deeper dish on the pistons as others I have seen.

 

check out the following:

http://gmcclassics.com/
http://www.california.com/~eagle/
http://www.gmcmotorhome.com/
http://www.gmcmotorhomes.com/
http://gmc.mybirdfeeder.net/GMCforum...frm_id=1&rid=0

my guess is that they used the healthiest toro motors/drivetrains there were.


bill

 

Bill, thanks for the info. From what I saw at first glance, looks like they used several motors in the GMC motorhomes. I thought they were all 455's. It'll take me a while to weed thru those sites, but I'm sure they'll give me all I need to know. I had to trade out the crank for a stick crank, as my 442 is a 4-speed. Luckily, the motor I bought would hone at standard bore, and the crank I bought was .010-.010 and a good'n. I put all stock stuff in the motor, except for an Edlebrock Performer manifold, 660crm Holley, and a HEI distributor. The only internal difference I noticed from generic 455's is that it had a windage tray and baffles in the oil pan. Motor is strong, plenty of power for driving it 50 mph back and forth to car shows, and cruises nice at turnpike speeds. Thanks again!!

 

I think your pan is a stock Toronado pan, you may consider reworking the hump to allow the oil at the front to drain when changing oil. Also, that pan holds an addl' qt..

 

yw


bill

 

Did you happen to grab the trans as well? A lot of those motor homes ended up with the switchpitch TH400s, never a terrible thing to have.

 

I think they had the th 425 aka toro transaxle.

 

No, I didn't get the tranny. The reason the seller had the motor was that he'd bought the motor/tranny together just to get the tranny. He had a motor home, and knew the trannys were hard to get, wanted one for a spare but didn't need the motor. I figured the pan was just a normal Toro pan, but was glad to see the windage tray and baffles in it. I'm not too worried if some of the oil doesn't drain during change. The 442 it's in gets the oil changed about every 2000 miles anyway, and looks almost as clean as when it was put in. It leads a pretty easy life...... but it deserves it, the car was almost not worth saving when I drug it home. It had been cannibalized pretty badly, and had laid in the dirt soooo long that the front brake drums were completely rotted thru.

 

yes, they used the toro th425 trannys, i doubt they were ever switch-pitch though. gm killed the s.p. at the end of '67.


bill

 

Bill is correct. The Switch Pitch was not made after the 1967 model year.

 

Yes, but it was a popular conversion. I'd forgotten the motorhomes used the 425, though. Fitting the 425 or a 400 with a SP was not a major operation, though, given a case that could use it. Later cases lacked the proper stator oil passages needed.

 

If you have a Toronado yes getting the motorhome transaxle would be a good thing if needed,but for a 65 cutlass not so much.