56 chevy 7004r trns

If want to up grade my trans from the 350 to a 7004r, anyone know what are the best years to look for at the wrecking yard, it will go behind my 350 stock cam 4bbl. Also , what torque converter to use and can I just use a toggle switch to lock it?

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56
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Reply to
gnospammurray

I think I'm with the other fellow--the late Turbo 350 is much more dependable than the 700R4. Unless you have an awfully good reason, I'd leave the 350 in there. If the current 350 is shelled out, rebuild it or find another one at a salvage yard. The 350 will be cheaper to buy and cheaper to rebuild.

Free advice, worth every penny you paid for it.

Reply to
myford100

Reply to
Jay Anderson

What about changing the rear end to a high gear ratio

Reply to
sparky

Because I really want the original question answered, I guess no one knows how to answear it.

Reply to
56

An 88 or later 700r4 is pretty good. Most of the bugs had been worked out of them by then. Even so, I have an 84 that I rebuilt and updated a few parts in. Wasn't very expensive either. You can pull a 45 degree 700r4 out of any astrovan and it will work just fine. I would use the stock converter.

Reply to
omicronelectronics

Thank you. would the v6 trans work as well as one from a v8 car? I have a line on one from a Cadillac.

Reply to
56

I went this route in my '70 Blazer and am very pleased (after a few testy times). I have a lower first gear and the higher overdrive. Be sure you get a "heavy duty" (for trucks) torque converter.

First choice would be for you to get from a dealer, a rebuilt 3yr/36,000mi warranty for around $1200, with a manual shift valve kit installed (if possible). I believe this would be for a year before '88 and possibly '86 or before. In any case---pre computer. I believe the only thing you might need extra would be the adjustable bracket that mounts on your intake manifold to support the shift cable. (There is no vacuum shift on the 700R4).

2nd choice would be a "good" rebuilt with the same 3 yr/36,00 warranty. I would NOT recommend a non rebuilt unit. There were problems with the early ones, just like the early 350's and 400's, improved with different valving, materials and parts. Post here in this news group if you need more info. LD

Reply to
LD

Unfortunately the v-6 and the v-8 bell housings are vastly different in size due to the fact that the v-6 is a 90 degree engine while the v-8 engine is 45 degree (the v-6 bell housing is much narrower than the v-8). The only exception that I an aware of would be GM's 4.3L v-6 which is the

45 degree design. Also, GM's 3.8L is also a 45 degree design But am unaware of any rear wheel drive vehicles that used a 3.8L. I am curious....what size and year is that caddy tranny you have access to?
Reply to
omicronelectronics

Also, regarding lockup....A toggle switch in line with a brake switch (you need the kind that opens a second set of contacts as well as closing a set of contacts for the brake lights when you mash on the brakes). You should be able to a switch out of just about and mid to late eighties gm car or truck. But if not go to a parts store and ask for a brake switch for an 84 firebird w/auto tranny or similar car. The reason for this switch is that you don't want the converter to be locked when you start braking so the switch will interrupt the circuit and unlock it. Another thing is there is a 3-4 switch in the 700 that is used to make sure the converter doesn't lock up before 4th because the converter needs to be unlocked while the tranny is shifting. There are kits available to handle the lockup of the converter that cost around $70.

Tpiperformance.com seems to have a nice little kit for this.

Reply to
omicronelectronics

Also, regarding lockup....A toggle switch in line with a brake switch (you need the kind that opens a second set of contacts as well as closing a set of contacts for the brake lights when you mash on the brakes). You should be able to a switch out of just about and mid to late eighties gm car or truck. But if not go to a parts store and ask for a brake switch for an 84 firebird w/auto tranny or similar car. The reason for this switch is that you don't want the converter to be locked when you start braking so the switch will interrupt the circuit and unlock it. Another thing is there is a 3-4 switch in the 700 that is used to make sure the converter doesn't lock up before 4th because the converter needs to be unlocked while the tranny is shifting. There are kits available to handle the lockup of the converter that cost around $70.

Tpiperformance.com seems to have a nice little kit for this.

Reply to
omicronelectronics

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