View Full Version : Some help and recommendations
Kinetic Dan
11-06-2007, 06:51 AM
Hello folks!
Can anyone help me, I'm trying to figure out what autobox I have behind the factory stock Chevy 305 in my 79 Cutlass. Its a 3-speed column shift.
I'm going to be purchasing a crate 350, probably built to around 400hp, can anyone recommend a new autoto suit, since I might as well get a recon'd box at the same time?
astroracer
11-06-2007, 08:46 AM
TH350...
You may want to consider stepping up to an O.D. trans. A lot of potential for rear gear changes and keeping the RPM's livable on the street.
Mark
My 79 Caprice had a TH250 unit, this was pretty standard. They are very weak. Sorry I cannot tell you how to ID the difference from a TH250 from a TH350.
GetMore
11-06-2007, 06:18 PM
I second the recommendation to go with an overdrive unit.
Your stock transmission could be a TH-350, which is relatively strong, and may hold up to your crate engine, or it might be a TH-250, which is rather weak.
When you drove the car, did it seem to have 3-1/2 gears? The TH-250 had a lockup converter, so it would shift up through the gears, and then at light throttle, over a certain (low) speed, it would lock the converter, dropping the rpm a few hundred rpm. It wouldn't drop as much as a gear shift, but it was noticable.
The overdrive transmission that will probably be the best (easiest) fit is the 200-4R. It came stock in those cars in the mid 80's.
The 700-R4, also called the 4L60, and then when electronic control was added, the 4L60E, is a popular upgrade.
The 4L80E is the strongest, and as such, the most expensive.
Both the 4L60E and 4L80E require a controller, which will add to the cost.
One of the biggest questions is how much do you want to spend, and what is available to you?
I don't know what parts are available to you, or if you are planning on having the transmission shipped over to you.
Kinetic Dan
11-07-2007, 04:54 AM
I reckon I have a TH-250, as it indeed seems like 3.5 gears!
I'll probably find someone who's rebuilt a 200-4R in the States and ship it over, any recommedations there?
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