A-Body Driveline setup

[mroverlord]

I have a mild 360 in my '75 Dart My engine is a .30 over 360 , 625 CFM Carter, Edelbrock Airgap intake, ported 576 heads, .485/.465 Cam and street headers. I have heard all about the trans debate I have been told a good 904 will work fine, but I have also been told to hunt down a 999 trans - which supposedly is alot more durable and doesn't require modifying the car like a 727. Also my car car has a 8.25 rearend with 2.43:1 gears. My plan is to install a powertrax limited slip unit and 3.21 gears. Is this wise? Will I need heavier axles? Can an 8.25 rear take the power/torque? Will the 904 suffice if properly rebuilt with stall / mild shift kit? The car is intended to be a street cuiser and won't see the track but a few times for reference time slips (this is not to say that it won't be driven hard, just not raced).

[DartMan360]

Stay with the 904. Expecily if that is what the car already has. You wont have to worry about driveshaft length. Just rebuild it put a good shift kit in it and a good converter. The 904 will be faster than the 727 because of less rotating mass. We have alwise used 904's in our race and street cars. I would recmond using the turbo action shift improver and if your going to rebuild it go ahead and use their rebuild kit also. A 10in 3000 stall converter would be ok for your set up. As far as converters we only run and I only recmond Coan. They are expensive than the rest but you pay for what you get. Call and ask for Craig. He is great at what he does.

As far as the rear end. the 8 1/4 will take it. Just get some nice gears and you will be a happy guy. If you do have the extra money you might want to switch to an 8 3/4 but I think the 8 1/4 would be fine. Our convertable is a mild 360 like yours and it only has a 7 1/4 with 2.76 gears and it has been in the car since 94.

One thing for your motor I would recmond using a bigger carb. somewhere around 700-750. A thermo Quad was probly on their which was 800 or 850? I cant rember what the lower one was. This set up should get you deep into the 13's with a good street tire and muffler. Maybe 12's with a street slick and open headers.

[mroverlord]

Well - the driveline info is reassuring- I actually stepped down from the Holley 750 dual line to the 625 Carter Electric choke. I was always in the school of thought that it's better to run a bit lean than too rich and bog the motor down. But then again this is the first time I've ever built a street rod, all my previous work was on restorations - so I've been getting alot of info from more experienced mopar rodders. Also I figured I didn't want a big carb because I didn't want to run rich in the city streets (I do live in Arlington, TX) and I'm not going for all out times at the track.

[DartMan360]

On the tech side of things it is safer to run rich than lean. If you run lean it is still going to bog the motor down or starve it. We have the carter 625 on the covertable for show purposes. WE put the the Holly 750 with alot of jetting and aftermarkit stuff it it was like night and day. Also I have heard than when you run rich you use less fuel.