85 Mustang updating

[fshtrollerx@cs.com]

I have an 85 GT that was a fast car in its younger days. I bought it as a rolling chassis to have fun with.
Car has 10pt cage 7.5 cert. Mosher 33 spline axles, 4.10 gear, ssm lift bars, mac rear end cover, comp engineering adjust uppers, racecraft wing, fuel cell msd 7al2 tubular control arms, aerospace front brakes, rear dic, coilover on stock struts.
Engine is Roush 347 500HP@6000 Hyd cam carb (780) Solid engine and motor mounts, elec fan and motosport radiator.
Tranny is chevy pg 10" TCI converter and Tbrake.
Street legal and run thru the Headmans and 3" flowmasters.
Car runs 11:70@115 on Street slicks. 1.63 60's, 4.7 330's and 7.40 1/8.
I am being told that I need more HP (I don't want that) or put in a 3 speed C4 or Turbo400. Also to up the gear to 5.46. The 400 might be an easier swap since it already has a plate for the glide.
I want to do this in steps and I am looking for suggestions.
First change is to up the RPM from 62 to 66 and see what happens.
I am an old racer and this is my first ride without a clutch. I don't understand the Auto thing, but I sure enjoy the ride. I race out of Ubly dragway when I get a chance.
Any suggestions?
Thanks

[powerjames]

Welcome to the site. Sounds like a nice project. Just a FYI - 10 pt cages now only cert to 8.50 instead of 7.50. For 7.50 you need to have a 25.5 spec cage.

I will tell you now - at your power level; the PowerGlide is killing you. You need to go with a C4 without a doubt, unless you up power into the 750 hp range. The Turbo 400 is not nearly as efficient as a C4 and you'll give up lots of power.

The C4 will bolt right up.

Originally Posted by fshtrollerx@cs.com

I have an 85 GT that was a fast car in its younger days. I bought it as a rolling chassis to have fun with.
Car has 10pt cage 7.5 cert. Mosher 33 spline axles, 4.10 gear, ssm lift bars, mac rear end cover, comp engineering adjust uppers, racecraft wing, fuel cell msd 7al2 tubular control arms, aerospace front brakes, rear dic, coilover on stock struts.
Engine is Roush 347 500HP@6000 Hyd cam carb (780) Solid engine and motor mounts, elec fan and motosport radiator.
Tranny is chevy pg 10" TCI converter and Tbrake.
Street legal and run thru the Headmans and 3" flowmasters.
Car runs 11:70@115 on Street slicks. 1.63 60's, 4.7 330's and 7.40 1/8.
I am being told that I need more HP (I don't want that) or put in a 3 speed C4 or Turbo400. Also to up the gear to 5.46. The 400 might be an easier swap since it already has a plate for the glide.
I want to do this in steps and I am looking for suggestions.
First change is to up the RPM from 62 to 66 and see what happens.
I am an old racer and this is my first ride without a clutch. I don't understand the Auto thing, but I sure enjoy the ride. I race out of Ubly dragway when I get a chance.
Any suggestions?
Thanks