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THM350 vs 700R4

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EDNY:
Jef

Thanks for sharing your knowledge.  I'm kinda a fan of the 700R4 tranny and TPI, the combination allows me to use the ECM to shift and lock up the OD tranny.  I still see a lot of guys building cars with the old reliable 350THM (without overdrive?).

For the guys running carbed engines doesn't it just seem more practical to run a 700R4 or if you can locate one a 200R4? Are they just as strong as the THM350 or even THM400 for street use?

FYI: I'm installing a 1995 LT1 engine in my sons 37 Chevy and will be controlling the 4L60E via the ECM.

Thanks
Ed

Cool53:
Hi Ed,
I find a lot of people still running the 350's for the simple fact that they are a great transmission and there are plenty of them still around. One step better is a THM350C. The lockup converter on the C reduces converter slippage about 18% on cruise. But I hate to sacrifice speed, especially quarter mile speed, and the best way to go quick is with a lot of rear gear. I run 4.10's in the truck with a 25" rear tire, and with overdrive and lockup I am only turning 2800 rpm at 70 mph. I build a lot of 700's, and have some really fast cars running them with no failures. The last couple of years I have switched to the electronic versions, the 4L60e and 4L80E to have more fun and to have a more versatile transmission. I recently built a 4L60E for an 800 hp BBC in a deuce. When you get to those numbers the transmission parts get expensive, but for transmissions under 500 hp with slicks most of the stock hard parts are just fine.
Another thing nice about the E transmissions is that you can buy a really awesome controller, UsShift, formerly Optishift, that makes even a stock E transmission a butt kicker.
So if you want to go quick you need gear, if you want economy put an overdrive trans with lockup in front of it and you've got the best of all worlds.
I will follow this up with some info about picking out a converter soon. Jef

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