P30 chevy car hauler

[hillguy]

have 1980 P30 turning into car hauler 454 engine w/400 turbo thinking of changing to 700r4 or adding gear vendors overdrive. Ideas on which would be better?

[95 S_Trucker]

Originally Posted by hillguy

have 1980 P30 turning into car hauler 454 engine w/400 turbo thinking of changing to 700r4 or adding gear vendors overdrive. Ideas on which would be better?

What is your top speed you want to drive? What is your rear axle ratio? Height of rear tires?

A 700R4 would be a poor choice in anything that weighs more than 7,500 pounds.

A TH400 with 3.73 or 4.10 would be able to cruise at 60-65 all day long. 4.56 + would be another story.

[sweetk30]

no to the 700-r4 in that weight class.

if over drive go 4l80-e or gear vendors .

gear vendor is 0.78:1 and no lockup drop of 200ish rpm and cooler running trans .

4l80-e is 0.75:1 and has lockup for more rpm drop and cooler running trans from no slipping hence lockup .

4l80-e has same gear ratios as th400 but overdrive gear and convertor lockup to drop rpms by around 800ish at highway speed.

if 4l80-e check these guys out . www.usshift.com for stand alone controler .

and play with this for your rpm's at a given mph . http://www.grimmjeeper.com/gears.html

rpm's @ 70mph with 215/85/16 common size in the 80's

3.73 = 3050
4.10 = 3353
4.56 = 3729

if 4l80-e overdrive locked up installed gets you . remember these #'s drop back to above if pulled out of 4th overdrive gear . minus around 200rpm for lockup .

3.73 = 2165
4.10 = 2380
4.56 = 2647

remember tho you need to hit your middle power band of the engine at cruising speeds so the engine is not bogged down to much and has room to climb before top out of torque curve falls off. so lowest is not always best in a work truck hauler .

you might even wana go deeper than 4.56 if you run overdrive so it gives you a big power advantage like a longer pry bar .

[cal30_sniper]

I tried a nicely built 700r4 for towing behind a 454, it didn't last long. Not recommended.

I like the TH400, I wish I would have kept it instead of doing the 700r4 swap. In the end, I went to an NV4500 and never looked back. Awesome trans for towing with a big block.

[Pyrotechnic]

I've considered a gear vendors many times, but given the super high price it sells for and the fact that after all that you still don't get a lock up converter, they are simply not worth the money.

Keep the Turbo 400 and deal with high cruise RPM's, or get a 4L80E and a shift computer.

[95 S_Trucker]

Out of curiousity, what is the GVW of your P30? Most are 10,000. By the time you but a cab and bed on, you'll be around 7500-8000 pounds(more if you are using a moving bed). That doesnt leave much weight for a car on the back.

[truckfan]