I have a 72 Cutlass with a 350 and 3 speed center console trans (TH 350?). Transmission is starting to slip. I will upgrade engine to 455 within a year and wondering about getting a trans that will fit both engines so...

1) Will a TH 400 fit both a 350 and 455?
2) Suggestions on transmission (old/new school) to put with a future 455. This is a daily driver so contemplating additional overdrive to attempt to squeeze out some mileage in the teens.

 

yep i run a th400 on my 350 and it will bol right up to a 455.

 

Excellent. Thank-you. Any ideas on adding an overdrive in the mix to the TH 400?

 

That's a common thought. Yes you can hook up a 200R4 or 700R4 for overdrive. It will bolt onto either of the 350 or 455's and give you that extra overdrive gear you're looking if economy on the road is your goal. Mind you a 455 is not designed to be economical.

 

As usual - I was able to find some pretty dead-on threads with a little more research - anyone see testimony as to actual mpg results of the 455/200-4R combo as opposed to 455/TH 400 (13ish with very soft feet).

 

Well, I can't speak to actual. I did a little on line searching on this for you and found this over on the Chevelle forum

Note: final drive is transmission Gear ratio X axle gear 3:73 or 3:42 in this example. If you are running 2:73 or 2:93 (likely if it's a Cutlass 350) the final drive will be even lower. The 455 will simply give you way more torque and HP over the 350. So it will move your car nicely when you want and still stay practical for highway. You should be able to determine what gear ratio you feel comfortable with. Don't see any problem with you getting decent mileage in the teens even if you just went 455/400.

 

Thank-you for the ratios. I will check mine and confirm my suspicion of 2.73. The goal here is to get 300/tank on nice driving or so I can get to the beach without stopping. I.E. 15 mpg with a 20 gallon tank when I am on good behavior. (It is 20 gallons? I guess I could add a fuel cell but do not want to make a huge mushroom cloud.)

 

My experience is with a '66 Chevy full size wagon with a 427 and 3.55 gears.

15MPG highway with the TH400, 19MPG with the 700R4. The locking torque converter increased urban/city driving a couple MPH (14 to 16MPG). I drive it rather easy to get those numbers.

 

I still like the Turbo 400 for ease of install.
I have both a 700r4 and a 4l80E and just don't want the electronic headaches of the lock up converter.
How many of you guys have done this swap?
Any other tips appreciated.
I really like the strength and performance of the original Turbo 400.

 

200r4 and a 700r4 aren't electronic they run off a TV cable and the only electronic part is the lockup torque converter which runs off a pressure switch inside the transmission. I just put a 200r4 in my 65 and it was very easy to install and make work properly with a few simple aftermarket parts.

 

More details please.
I would like to run overdrive,but don't want to burn up the trans either.
I have a 1991 700r4 out of a truck.
Thanks.

 

There is nothing "electronic" about the 700R4 or 2004R converters. A simple switch will do. The lockup selenoid 's power is either on or off. Factory installations controlled it's power (or ground) via the ECM.

If you wish to become a little more elaborate, power to the selenoid wired through a pressure switch(s) will give a bit more automatic function to the converter locking/unlocking. A 2004R conversion I did I also used a pressure switch plumbed into governor pressure to lockout the converter clutch below a certain MPH.

 

You need to rebuild either a 200r4 or 700r4 if you want it to survive behind a 455, so it doesn't make much difference what it came from to begin with.

I think adding the overdrive to my car was a very good investment.

 

I wouldn't spend the cash on a 700 rebuild,as they are probably more expensive than a Turbo 400,which are nearly indestructible if you take care of them.
I tend to abuse my Transmissions,but I change the fluid a lot.
Lots of high speed down shifts coming off the highway,and hard 1-2 shifts...Like to show off.
I have the 700r4 sitting here collecting dust,so I may try it out and see how I like it.

 

Shifting gears a little. Riddle me this one - all things being the same, if my 0-60 is 8 seconds with a 2.73 rear, what do you think my time would be (abt) with a 3.73 rear end? Just curious.

 

Faster?

 

I would think, but by how much idk? 1/2 sec. can anyone else chime in?

 

Have to use this and rpm as your shift points.
Knowing the top speed in each gear and torque peak/rpm should make a good estimate.

http://www.catherineandken.co.uk/sti/tyres.html

 

No, but probably QUICKER...

 

The 700r4 will give you quicker acceleration with it's 3.06 first gear, but some will argue the difference is too much going into second gear.
I personally think the low RPM torque of a 455 can handle it with ease, and can really help if you've a rear gear in the mid 2's to mid 3's!
Prices have really come down on these, both in stock and modified form, too.