700r4 torque converter question...

I'm a few $'s away from rebuilding my 700. The rebuilder was talking about 2 different routes to go with the torque converter. One is a stock type that locks and unlocks. The other one does not lock/unlock. He prefers to put in the latter style and said he used to run one in his 500 hp 'vette. I'm wondering what the difference is between the two (drivability, mileage, longevity, etc...). The tranny is going behind an RV cammed 350 in a 51 Merc. The tranny will also have a shift kit/improved kit in it and be non-electric.

 

I run a stock type with low/stock stall behind a 454/700R w/3.42 gear. It's also going to run hotter if it doesn't lock-up

 

non-lockup will get less mpg, generate more heat and have a shorter lifespan.

For your use, go with a plain 700r4, install a few minor updates like a hardened sprag and a vette servo, shift kit, etc. Then maybe opt for a slightly higher stall speed, maybe 2200 rpm. Be sure to keep the factory lock-up function working through a brake switch. (no taggle switch!)

You'll be very happy.

Maybe find a new transmission guy first....

 

Thanks Scotty, I'll nail down the specifics when I talk to him again and ask for the upgrades you've suggested.

 

I put a hydraulic lockup converter in the 700 used in my o/t car at the advice of the valve body builder. Basically it locks up at 50 mph and kind of makes the box feel like a 5 speed. It's great for highway cruising but it would be nice to have an unlock feature when downshifting. The benefit here is no wiring to screw up and cooler operation. The electric kits offer an unlock feature but are arguably more complicated to hook up. I cannot comment much on putting a non lockup converter in a 700 for street use. At first glance it would seem like it's going to run hotter and get lower fuel economy.

 

The electric lockup kit is not at all hard to install. Run the one with the vacuum switch too.

 

I have a Bowler lock-up in my 700R4, it works great except when going slow, if the tranny stays in 4th, the lock-up stays locked up also instead of unlocking as a vac setup does. Hope this helps.

 

pressure switch that locks / unlocks when 4th engages or downshifts. No hassles and use a monte ss converter, stall performance should be just right.

 

x two on this input,