TH350 Front Pump

[Chad E532]

Are there any measurable gains to be had by swapping out the stock front pump on a TH350 for one of the specialty race only pieces made by TCI, ATI, or other manufacturers? Do they require less horsepower to spin?
I still run a stock pump that has not had any modifications and I am doing some winter refurb so now is the time to change it out.
Let me know your thoughts on these high perf pumps.
Thanks,
Chad

[buzzinhalfdozen]

My understanding there are 2 types of aftermarket pumps. First they have an increased volume pump which is pretty self explanitary. Second they have a reduced volume pump which is used in alot of Comp applications, pumping less fluid requires less HP. I believe it would depend mostly on your application. My trans uses the reduced capacity pump however I'm sure there are some applications that it would not work well in. Joe

[Alan Warman]

You can take the pump body to the machine shop have .100 cut off the body and gears. ( The .100 I used is just a example some cut less some cut more) You will have to re cut the pump body O-ring grove or some people just run RTV around it. So does anybody have any other tricks they would like to share.

[Chad E532]

Thanks for the replies.
My application is a 350 powered mid 11 sec Pro ET car that is morphing into a stocker. Are the after market pumps just machined stock pieces or do they offer other benefits?
Thanks,
Chad

[Mike Taylor 3601]

Coan low volume I had was stock 350TH pump gears and housing milled down.Coan told me worth 6HP
@ wheels. I didn't gain 1/8 mile was told would be more of 1/4 mile improvment.I put low gear set in
at same time I think it made my converter that was already on the tight side tighter{lower gear set makes
converter tighter because multiplies torque more} and cost me any gain I should've seen,only difference
I could tell was normally running 45-50psi in front tires had to drop air to 30-35 to slow
reactions times back to same spot on tree.BTW if you want low gear set for 350TH they are made
from 700R4 planertary modified to fit 350TH If you have the skills you can make your own.
Mike Taylor 3601

[Chipper Chapman]

Aren't the 700's a 3.06 low gear not a 2.75?

[Mike Taylor 3601]

I think they are 3.08 in 700 but when in 350 2.75/1.57 we compared 350 low gear set with 700 planetary
couldn't see any difference besides plate w/bushing to adapt it.
Low gear uses both gear sets to make low gear. Bracket that holds park rod was different and I think
rear piston was modified to clear gear set? I did that about 7 years ago so can't remember exactly.
If you have enough skill or have someone that can help you could take 350 and 700 apart and
make your'e own gear set,but if you have to pay someone to do it probaly be as well off to buy
one or buy the first one so you can copy it.
Low buck lightweight drums,250TH looks like 350TH but has band adjust screw on side of case
Has sun shell w/holes in it some have hole horizontally some have vertical and horizontal holes
rear shaft is gun drilled drums are lighter I think about 5-6 pounds lighter rotate weight all together.
Mike Taylor3601

[Chipper Chapman]

Ok good to know, i forgot about the 2 sets working together to make low gear. I have a 250 here for parts and when i build was planning to take it apart at the same time as i heard of using the 250 stuff to lighten them up. Also i have 200 to build but i'm leary of the longevity of it, the car will see frequent bracket racing so i think i'll make the 350 my primary.

[Mike Taylor 3601]

I have 200 turbo action valve body and 200 pump started rework to use 350 converter,housing is bored
for 350 bushing&seal have 200 gears cut for 350 converter need input shaft and stator changed
I was told attach modified 700 shaft to 200 drum. stator from 350 modified to fit 200 pump.There
may be better way but that's what I had came up with.Valve body is used bought from Paul Crowe
he went to PG when he went crate motor.Would sell all for $150.00. Also have some 200 pieces
I'll throw in. Have 350 coan rev pattern manual sell for $100.00.
I'm ashamed to say it but I tried automatics I'm not proud of it but maybe if I warn others maybe I can prevent them from making that same horrible mistake.LOL
I'm a stick man I don't need these auto parts maybe I can turn them something I can use.
Mike Taylor3601

[Chad E532]

This is all very good information on swapping internal components for gear changes, however if I can steer this post back to where we started.
Is it worth the money to go to one of the trick after market pumps or is it a minimal gain for the cost?
I see that TCI lists two options on the pumps one that is more of a modified street version and another that is for "class race" vehicles. Has anyone tried either of these pumps?
Thanks,
Chad