Is there any difference in a 350 turbo trans used on 6 or 8 cyl. GM motors?...is the torque converter different?...or the gearing? I'm pretty sure the powerglides have a bit different gear ratios but not enuf to matter really. ...I've got a 350 turbo, don't knnow what it came out of, and I want to use it on a 292 Chevy inline 6. thanks
Squirrel might know................he's a pretty smart feller' on these types of things....... My guess would be: converters are different, if anything, as in stall speeds, I would guess the 6 cylinder one would be higher...............
I think the main difference in TH350's is the number of discs (friction/steel) in the clutch packs, depending on it's original intended application. They can be upgraded easily by changing to the appropriate piston (thickness) to accommodate the greater number of discs. If the tranny is is good shape at present, I doubt "normal" driving would present a problem..........if occasional "heavy duty" use is intended, maybe a disassembly and a look see would be justified. Ray
"glide has either 1.76 or 1.82 low and 1 to 1 high. T350 has 2.52 low ,1.8 (or so ) 2nd, and 1 to 1 high.. T350 will get off the line easier / better.... You may have trouble finding the correct flexplate for the 292. They use 1/2" bolts on the crank flange.. I have seen drilled out small block flex plates used on 292's with no problems.. Good luck Dave
the stall speed is not the only difference, the 6 cylinder units had taller pistons in the drums...that means less clutches. Forward drum has 4 ,direct has 3, a 6 unit can be turned into a 8 by cutting the pistons down and stacking in more clutches. We also cut V8 pistons down to hold 6 clutches.
...soooo, if this is a V8 trans, will it work ok on the 292? ...can I redrill the flexplate for 1/2 inch bolts and is the center register hole on the flexplate for the crank flange different? (I'd check it myself but the motor is in another storage bldg. and it's been too dang cold to get it into my shop)
Three dowels on the 292 along with 1/2" bolts. You could probably make it work, the center hole is the same afaik Like only said, the clutch packs aren't as thick on the 6 (and 307) versions of the TH350 compared to ones for 350 applications. Mild 292 in a relatively light car should be ok with the stock setup no matter which version of the TH350 it is, but if you build it swap in the shorter clutch pistons. And in my experience pretty much every used TH350 needs to be rebuilt. also look for the little screw on the side to see if it's a TH250
You can redrill the flexplate. Or you can buy a new flexplate for the 292 for about 35 or 40 dollars from any number of suppliers. The 6 cylinder GM cars used an 11" torque converter on the 6 cylinder cars. The eight cylinder 350 may have more fictions and steels but it may not truck applications used more plates. The 6 cylinder used lighter springs in the governer, but you can deal with that by buying a shift improver kit and fiddling with the springs until you get the shift points that you prefer.
i remember back in the "really poor days" having the work truck trans going out and having to adapt a "air cooled" powerglide out of a 65' nova behind a 454 in a 3/4 ton truck and it lasted 2 years until we decided to replace it with the old 400 after it was rebuilt. it probably lasted because the motor was worn out also.
The 6 vs 8 is a mater of torque converter stall and the number of discs in the clutch packs. Many times I have shaved the pistons on a lathe and added more discs. That is, or was a common procedure. GM used the same trans for both 6 and 8 applications. It used to be common for a racer to use a 4 cyl or 6 cyl converter to take advantage of a much higher stall speed when used behind a V8 with a lot more torque.
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