rennoc442

Ok I need to get my 70 cutlass a better trans, a turbo 400 is stout, but my wallet for gas is not. (I plan on driving 75-80mph 100miles round trip on weekends)

What would be cheaper/best way to go, a 4spd auto that can live behind a 455 with about 500 lb of torque, or a 5 speed tremec?

If I were to get the 200r-4, or a 700, I would want to replace my console shifter to a dual gate, with the provision for the 4spd setup.

If I went the manual way (fun way!) I would need to set up the crank to accept the throw out, and possilby modify the tunnel area. That and modify my console to accept the manual, be it a rubber boot, etc.

I already have a bellhousing for a manual, and the clutch petals to add to my 70, but would need linkage or I am going to guess go hyd setup.

So any suggestions/ideas? I think I saw on ebay some stores selling a complete t-500 setup for under $3,000. Im sure if I went with a 700 it would be more then that (mind you the shifter).

rennoc442

OH also the rear is a fresh rebuilt chevy type 3:73 posi.

Rickman48

4L80E would be the best of both worlds, and I believe they also have console adapters!

MX442

Real hotrods have 3 pedals.

rennoc442

4l80E??!! Thats a huge ! lol I think I would shy away from the e, and maybe just get the 700r4. Same trans but no electric to worry about.

But then again in the future when I run an EFI system, adding in the E would be a breeze

What do you mean console adaptors?? I would get rid of the shifter now and put in a dual gate, or some rods!!!

rennoc442

Thats where im leaning towards! I love the feel of a 5 speed manual!

67cutlass67GS

While the stick is fun & looks good we all know what happens when that nanno second of clucth kicks in & the automatic walks on by...LOL. Equally matched of course...

garys 68

The TKO will require cutting the tunnel. If that's not an issue, go for the 5 speed.

Rickman48

Unless you know how to powershift!

67442HT

I have installed many TH700R4 transmissions in performance cars and trucks and have one behind a built up Big Block Chevy in my very heavy 77 ElCamino now. I have run the dog out of it for 18 years with no problems. They
can be easily built to hold up to a Big Block, and will fit in your car with the least amount of modifications, no tunnel or console changes and you could then add the dual gate shifter.
ps: I own an automotive and transmission shop and would be glad to help you with your change over if you need any advice. Charles

ATrain1

I would run with a 4l65 instead of a 4l80. The 4l80 will rob you of more HP. I would say you could go with the 700r4 if you want to deal with the TV cable, it is not fun. If you go with a 4l65 or 70 I believe they have 5 planets instead of 4. I used to rebuild all of these tranny's for racing. I owned BP performance and that is all we did. Just get the controller so you can run it with an older carbureted engine. Good luck

Nilsson

If it doesn't have a clutch you don't have much.

ATrain1

I guess it really depends on what you are using it for. My brother seems to think with the right close ratio 4 speed a guy could out shift a automatic, I strongly disagree. It has been my experience that a built automatic will get the job done in the 1/4 mile much faster than a manual. Now as far as manual transmissions go I think they are a lot more fun to drive. I would love to own a 78 Cutlass with a factory manual transmission. There is also the fact that you do not have to run a stall converter with a manual trans, so I guess it really depends on the application.

hotrodpc

I'm a 4 speed guy through and through. BUT, as bad as I miss them, I run automatics. They are dime a dozen, cheap to build and can still be a bit fun with the right shift kits, tweaks and a nice ratchet shifter.
As far as your question, the Tremec 5 speed has a chance in hell to hold up, the 700r4 Does Not. You can do some mods to the 700r4 and make it take a little more abuse but nonetheless, don't expect years and years of service out of it.
I'll agree with the 4L80-E suggestion if you're deadset on an OD trans. Can you get around the E? Yes you can. I'd say you obviously won't mind if you're willing to work a 5 speed and a clutch. The trick to running a 4L80-E without the E, is to run a full manual valve body and shift it yourself. No electronics needed then.

z11375ss

You need a lot of parts to convert that car to a manual. It was worth it to me. I am planning on a Tremec in the winter. The builder is 6 weeks out at this time and it is Hot Rod season here in Chi Town. Gotta drive em when you can. I have a friend w/ a 700R4 from Bowtie Overdrives that so far has been fine. Crossed fingers and all. It would be MUCH easier to stay with the auto than convert to a manual. Just my 2 cents.

allyolds68

So you're looking for better fuel economy for 5200 miles a year. At 14 MPG that's 371 gallons. If you get 20 MPG that's 260 gallons. The difference is 111 gallons or about $389. That's if you drive 5200 miles a year.

I guess that what I'm trying to say is if your looking for better gas mileage any standard trans is going to set you back a minimum of $2500 (and that's for your basic Muncie that isn't going to give you better gas mileage). I don't know what a good auto tranny with an overdrive costs but probably less than that. Either way it's a lot of years of driving your TH400 the way it is.

hotrodpc

That's the way I think. I've got trucks with 4.56 and 4.10 gears. I consider Gear Vendors overdrive units. After the math, I'm ahead of the game instead of making the investment that would take 11 years to get back. And that's if fuel prices stay where there at, if they get better takes even longer, if they get worse, it might not a year or 2 off the payoff. But. that's why I've decided if I do anything, I'll go with Full Manual VB 4L80-E, just non E.

Shradezz70S

I am doing a swap right now 1970 S 455 550 FPT 500 HP TKO 600 I little work, a few parts BUT a loy of fun...Take your time do your home work and do it right. GOOD LUCK