I plan on taking the '78 on the 2014 national corvette caravan and I want to at least be able to keep up with all those dad-gummed, fancy, new fangled phiberglass chariots.  On the 2009 caravan, once we got close to Bowling Green, we had a state trooper escort and we were doing over 80mph behind him for 20-30 miles.

VikingVette said:

yetanother dumb question from me.  What is the difference between a 2004R (like extreme automatics sells dor $1,496 and a TH700R4?  Is one a true 4 speed automatic and the other an overdrive unit?  I am like a lot of people in here.  I am not too concerned about the mileage, but I do not want to run for any length of time at 3200 - 3300 PRM (doing between 65 - 70 mph). 

 

Basically, a 200-4R is derived from a THM200 with better internals which in itself was derived from a cheaper version of the THM350. A 700R4 is derived from the THM400. The 700R4 became the 4L60 and then the 4L60E in the 90's and was used in Vettes, Camaros and trucks. I'd say the 700R4 is a tougher tranny.

My car is an '82 so it came with the 700R4 trans, I just rebuilt it. I'm sure either the 3.36 or the 3.55 rears would work fine, I just like that little extra kick off the line.

Just more info for the mix.

Dave

Thank you for that information.

 

Dave,

Thank you for your input too.  I remember your car from Charleston and it is a beauty.

 

First I need is a new radiator and getting the A/C working, but before the 2014 caravan, I would like to upgrade the transmssion and based on what you two jsut told me, I think I will strive for a 700R4. 

 

Again, Thank you both for your input. 

Excellent point.  Thank you.  Shortly after I bought this car (15 years ago) the original exhaust system broke.  When I got this car, there was absolutely NO pollution controls on it.  The exhaust place I took it to had nothing but straight sections of pipe.  He put my car on a lift, eye-balled a piece, got a piece of straight pipe off the wall, mandrel bent it, held up up to make sure it was OK (and it always was...he never used a tape measure), welded everything into place and spray painted the welds with high temp silver paint.  So I have a true dual exhaust.  When I had the ZZ4 put in, that guy installed Hooker Headers, so I have no idea how/if any piping would need to be re-done.  But you brought up a VERY good issue.  Thank you. 

Case75 said: This Wikipedia article explains it pretty good: http://en.wikipedia.org/wiki/Turbo-Hydramatic

Adams' Apple said:
I been kinda following along on this one, but I had to jump in...sorry...I just cain't help meself....


" itself was derived from a cheaper version of the THM350"
Uh...not....
Other than the steel checkballs in the valve body, and the use of Dextron fluid, there is absolutely nothing in a 200/2004R that is derived from the 350 series transmissions. These are two totally different transmission designs.

"A 700R4 is derived from the THM400. "
Uh...again...not...
The 700 is closer to the 350 trans, and even uses the same low/reverse clutches and steels, as well as the center support/low-reverse sprag. The 350(non-lock up) and 400 transmissions can use the same torque converters, but the 350 usually has a smaller diameter converter. The 400 converter will NOT fit the BOP(Buick/Olds/Pontiac) 350s, due to the shape of the bellhousing on those units.

All things being equal, and they rarely are, I would always go for a 700 over the 2004R. Yeah...I know...the 2004R is an easier swap, but the 700 is a better overall trans, with better 1st and O/D ratios. I've heard all of the guys claiming how stout the 2004R is, "They used them in the Burick Grand Nationals and T-Types". This am true, BUT...those transmissions had a LOT of upgrades done, and they still failed.
I do quite a few 700s for guys that are swapping them out for their 400 or 350s....I have yet to have anyone ax me to build a 2004R for them.
This am all just my opinion....I got no dog in this hunt, so....just trying to add a little more info.