More out of the hole

[RonnieK]

I've kept most of my purchases with the idea that I would keep my '68 Charger street/strip in the past but I have desires to start crafting the old girl towards race only mode. Step one is get it out of the hole faster which I know is a tough task at it's weight. It's a slow 2.1x '60 and I'm looking for thoughts and ideas on converter and gear ratio. Would like to push it as high as I can.

Current specs: 383 with the Isky Mega cam and Edelbrock Performer RPM heads.
Reverse manual valvebody 727. Car weighs 3500 racing. Footbrake car and prefer to keep it that way.
670 Street Avenger Carb. Runs on pump gas.
Caltracs suspension both front and back with 28x10.5/15 slicks to handle the starting line.
Car is open headers and has the Detroit TruTrac, Moser rear-axles.

Currently is a 13.6 car with a 2500 Hughes and 3.91. Thinking 3400-3500 on the stall and to go through Ultimate or BTE. Thoughts on 4.56 (Too steep?) and play with tire diameter for the traps? Maybe 4.30? I feel like 4.10 from 3.91 isn't a big enough jump but hence why I'm asking the questions. Thanks in advance!

 

[493 Mike]

I will suggest a 4.57 rear gear and then call a converter manufacturer for a recommendation.
Mike

 

[Black_Sheep]

390171 is a small block cam. That said, Isky recommends 3.70 - 4.10 gears and a stock converter.

 

[RonnieK]

390171 is a small block cam. That said, Isky recommends 3.70 - 4.10 gears and a stock converter.

Whoops. Must've had the wrong number.

 

[R413]

At what altitude is your track?

4.30 gears, more converter and a bigger carb.

Does the throttle pedal open the carb all the way? Check with a person push the pedal and see it you are WOT at the carb. Don't operate it by hand underhood.


Is it vacuum secondaries? If so try to speed up the opening.

Where is your timing initial and total?

What fan is on the water pump and is it belt driven or electric?

What rear wheels do you have, steel or aluminum?

 

[Curiousyellow71]

First..for race only my concern is what valve body and the transmission itself. Does it have low band apply or a bolt in sprag? Transmission blanket or shield? Not a big deal now at 13.5....but becomes a matter of safety as you proceed w slicks.
If it's race only and your not worried about driving there are plenty of convertor options both loose or tight.
But my suggestion would call PTC and order a 9 1/2" and shoot for 4500-5000. We also have a ultimate..they sell it as a 9" but it measures 9 1/2...marketing I guess. Also like our Dynamic.
9 1/2 are pretty streetable as well.

 

[493 Mike]

First..for race only my concern is what valve body and the transmission itself. Does it have low band apply or a bolt in sprag? Transmission blanket or shield? Not a big deal now at 13.5....but becomes a matter of safety as you proceed w slicks.
If it's race only and your not worried about driving there are plenty of convertor options both loose or tight.
But my suggestion would call PTC and order a 9 1/2" and shoot for 4500-5000. We also have a ultimate..they sell it as a 9" but it measures 9 1/2...marketing I guess. Also like our Dynamic.
9 1/2 are pretty streetable as well.

My Dynamic was great on the street, even in OD.
Mike

 

[PRHeads]

Which mega cam?
What’s the CR of the engine?

Fundamentally, my suggestions are 4.56’s and an 8” converter.
Then I’d go to a DP carb.

Running at tracks much closer to sea level, my 3670lb race weight 68 Satellite went a best of 1.51 60’ with a 906 headed 383.