700R4 torque converter questions.....

[Smokintire70]

Some one told me a 700r4 does not use a torque converter. I have also have heard that they do use one. If one could specify whether they do or don't that would be sweet. I want to put a cam (272 or 292 Comp hyd roller ) in my ramjet 350. Thanks guys.

[LongBox]

the 700R4 does use a TQ. Think of it as a TH 350, with an overdrive gear, and a lock up torque converter.

[Low69CST]

Without the lock up feature OD is pointless. The rpms will be below the stall level and the converter will allow slippage.

[hugger6933]

Yep does have a converter. My thinking is on the cam is the cam gonna play nice with the ramjets electronics? I thought they were non-programmable.

[Bigdav160]

I would think a little more stall in the converter is warranted with those cams. The lockup feature can be done without electronic control if the controller won't handle it.

[davepl]

It does have a TC, normally a lockup unit in factory config. For a 292 cam, you might need/want a looser converter.

[Smokintire70]

Originally Posted by davepl

It does have a TC, normally a lockup unit in factory config. For a 292 cam, you might need/want a looser converter.

What is a lockup? Does it lock the engine and transmission at a certain rpm?

[leftybass209]

Since you don't know much about the overdrive transmissions, you should go to bowtie overdrives website and do a lot of research. Putting an OD trans in a vehicle without understanding what's going on can result in a vehicle that runs like crap, a transmission that will burn up, or most likely both.

You have to consider cam spec, rear gears, RPMS for stall, 1st gear ratio, throttle valve connection, driveshaft length, transmission crossmember.... it's not a bolt and go affair 99% of the time.

[leftybass209]

The show Trucks! Once installed a 700r4 behind a 6 in a 49 chevy, you may want to search for info on that as well.

[davepl]

Originally Posted by Smokintire70

What is a lockup? Does it lock the engine and transmission at a certain rpm?

Yep. Strategy varies by model, but in most cases they won't lock up unless the transmission is in D and you're at a certain output speed. And there's usually integration with the brake switch so that it unlocks whenever you touch the brakes.

Ideally you'd never feel or know it's doing it, but it helps for mileage as there's then no slip, as opposed to just a little.