[Canuckwr]

I am looking to retrofit an overdrive into my 1967 Bonneville to increase fuel mileage and make it long haul friendly. It currently has a T400 and the motor is in the process of a rebuild from 400cu/in to 462 cu/in with a mild cam and some ported KRE D-ports, not 100% sure of rear gears but it felt like mid 2s. It will end up fuel injected and I know that these choices will need a TCU.

So, what will make the behemoth more happy and live for a healthy amount of time behind +500ft/lbs? I have no intention of racing, its a b-body, but having some snap would be nice. Nothing like shaking down some young punk with a new mustang.

I am leaning toward 4l80e as it will not need to be upgraded to handle big torque and the heft of the road couch.

Will a 4l60e handle this combo long? What would I be looking at if I went 4l60e and wanted it to last? I don't really have much experience with the electric autos in anything with power.

[69camarox]

just do the 4l80e and do it once 4l60e is weak

[Steve Barcak]

You a '87-92 era 700 r4 and save yourself a fortune and also have a lower first gear fr much snappier acceleration. I use them and tow with them, they work very well.

[Qball]

Is it possible to use a lock up torque convertor with a 700-R?

[madokie]

60 is derived from thm350.80 is derived from thm400.i would go with 80 , both are going to cost some bucks..a cheaper non-ecm way is to add gear vendors OD,diy capable,very reliable ,strong,no mods to carb ,or shifter linkage, or kickdown.my dad bought a 67 executive new ,4 door, thm400,400 2 bbl,big car, huge trunk,it was called the Batmobile at my high school.

[Cliff R]

+2 on the 87-92 4L60 deal.

We have several customers using 4L60's with zero issues anyplace. One in particular has a 69 Chevelle with a 500hp 454 engine and has logged over 50,000 miles and the car is raced frequently. I would use an 87 or later unit, as they already have all the upgrades. A 4L60E would be equally as good, but will require electronics for shift function.

Most folks with BOP engines go the 200-4R route as they have the correct bolt pattern and don't require an adapter. They are more costly to set-up than the 4L60's being pretty weak in several areas.

All of them can be set up for lock-up, although I prefer to use non-LU converters to simplify retrofitting. I've ran them both ways in my own vehicles and they just work better all the way around if an efficient well chosen converter is used for the application.....Cliff