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GM 6L50 for a rod...????

5K views 11 replies 4 participants last post by  Chevrolet4x4s 
#1 ·
The WIKI link I posted for GM trannys got me thinking....

I wonder what the dimensions are of the GM 6L50 six speed in comparison to a
TH350 or 200R4?

With the 4:11 rear end in my 1960 Vette and a Muncie M21, I need another gear or two for the highway....
 
#3 ·
The T56 is a manual and I'd prefer an automatic as I don't want to contend with linkage/clutch fabrication issues...

Also my present unit is using a scattershield and not a regular bellhousing...

From a driving experience, I prefer a manual but I don't want all the hookup problems (linkage, clutch) issues...
 
#5 ·
I understand your drooling love for the new generation of GM trannys. I've been looking at the 6L80 for a custom diesel I've been working on.

Not sure about sizes, but I've been told not be led into thinking its an easy swap. The computers in those trannys are onboard, but they still require all the computer inputs and more. Its like trying to adapt a 4L80E without the aftermarket support or anyone who knows the language to hack one.

It will happen someday; probably within the year. Some company will crack the computer, figure out how to get it to shift on its own, spend a few million testing their own, then offer it on the market. Until then I think the 6L family is just going to remain scary for most of us.
 
#7 ·
Provided its not too far from a stock engine, a 200-4r has an excellent close ratio spread, its lightweight, small, and has a nice .67:1 OD. If its a fire-breathing big block, 200-4rs are expensive to build at that level.

The 700r4 (although a fine tranny) is personally not one of my favorites. It has a fine 2-4 ratio spread, but the 1-2 shift goes from 3.06 to 1.63. Its horrible. I have a few 4L60Es (same basic tranny) and I hate them all. I've replaced one with a T56, another with a 200-4r, and the third one still plagues me. personal preference i suppose.

I've also heard of guys converting their T56 to a mechanical clutch. that would let you keep your stock clutch linkage and pedal and row 6 gears.
 
#9 ·
I'd strongly consider the 200-4r. It survived quite well behind 500-hp modified Grand National turbos, so it should be up to your 327. Usually monster torque is what kills them, so I rarely recommend them behind big blocks or in really heavy cars or towing applications, but in a small displacement car, do it and don't look back. You'll be happy.

I hope others chime in with some other opinions too....
 
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