Transmission Rebuild/ Upgrade

[dkinworthy]

Hello again Guys, Ok, Got the engine bay painted and engine installed, gauges rebuilt and all assembled and tested, now... My question is What to do about the transmission. I have the original 904, 2 truck 727 Transmissions, and I want to add overdrive. Should I have One of these rebuilt with mod kit or just go ahead and buy something new /rebuilt (from?) and already done? The Engine I will bolt it to is a 360 dyno @ 470 hp w/ 500 ft torque. I also installed rebuilt 8 3/4 posi with 323 gear.... any suggestions? Oh, not looking for a drag racer just something to have fun with (see album) and an occasional show if it helps. Thanks

 

[3406pk]

If you have 500 lb-ft torque, you should have the 727 TQ built w good clutches and shift package you want. If you keep the 3.23 rear gear, you shouldn't need OD. If you want the OD then get a Keisler Auto w OD (a modified GM trans made to fit mopar engines). I think the Keisler auto will fit w/o floor/tunnel mods.

 

[moparleo]

Like 3406pk was saying, with a 3.23 diff you don't even want overdrive. If you had it dynoed, what rpm range gave the best torque? That is where you want to be. Since this is a toy, go with a 727 for the LA engine. You will need a special flexplate to compensate for external balance. Being that you are also in So Cal like me, Check with Art Carr down in Orange County. Had him build me a pushbutton TF for an Early Hemi back in the early seventies. He knows his transmissions. Or B&M out in the valley. Bob Mazzolini Racing out in Riverside. A long time S/S racer. Lots of choices. You can play with gear ratios and Torque convertors to tune it.

 

[dkinworthy]

Thanks for the contacts Moparleo, and Thank You also 3406pk for the info. Max torque is at the 4400 rpm range (501) . whats with the non lock up I keep reading on trans adds? Sorry for the what might be dumb questions to some but I am not familiar with mopar :newbie: and cant afford costly mistakes. Oh, one more thing... why would I not want the overdrive if I am going to make highway trips on occasion? Thanks Again.

 

[moparleo]

rpm/mph calculator

:computer: Let me give you a couple of real usefull tools for calculating things like engine rpm vs tire diameter, gear ratio.

http://www.bgsoflex.com/rpmmph.htm

This is a very handy tool. Save it to your favorites file.

3.23 gear with 26" tall tire, 1:1 gear ratio, 4400 rpm =105 MPH.
That is why you don't want overdrive with a 3.23 rear ratio.

 

[dkinworthy]

nice THANK YOU!

 

[moper]

When I talk to customers about trans needs it comes down to the power level expected, and the intended usage. That's because if you are building a high powered, higher peak power engine package, the convertor and gearing need to work with it and because you want to enjoy the car, not worry or get irritated at how it behaves the majority of the time you're in it.
I would suggest the best convertor you can afford (Ultimate Convertor is who I'd recommend) and if you want overdrive I'd run the Gear Venders unit. That requires no mods to the car to fit, and is push button activated. You don't know it's there untill you need it.