1968 Plymouth GTX 4 Speed Conversion

[Molson1802]

We are converting an automatic GTX with center console to a 4 speed, possibly a tremec 5 speed. We have to add in the shifter tunnel. Is the shifter tunnel in the same location for all mopar b bodies in 68-69 with or without console? I would like to have the center console.

 

[Chase383]

Yes,

The "add on" tunnel section is the same with or without the console. You'll need the console brackets, and the shift handle is different for console cars.

 

[70mopars]

Don't take my word for it, but I think so. However the console on a manual car has an added fiberglass type plate added on to cover the hole on the hump. And if I'm not mistaken, the shifter hole for a tremec tranny would be more "above" the tranny as Mopar's tranny hole for the shifter is more "on the side". If you use the tremec, I think you can use the automatic console wihout modification, other than the top plate.

That being said, I vote for the Passon A-855 5 speed. A true bolt-in if using factory stuff.

 

[ChargerRTguy]

4 speed conversion

I converted my '68 Charger from an automatic to a 4 speed. Here is a list of parts that are needed, might be helpful.

 

[Daves69]

This is geared to A-body but may have some info and or numbers that are useful...............

http://www.bigblockdart.com/techpages/4sptech.shtml

 

[Molson1802]

Thanks guys. That list should do me quite well, thank you for that.

On a side note, I finally found a decent 68 deck lid, and a really nice 68 hood for my GTX. Almost all the metal work is done!

 

[451Mopar]

We are converting an automatic GTX with center console to a 4 speed, possibly a tremec 5 speed. We have to add in the shifter tunnel. Is the shifter tunnel in the same location for all mopar b bodies in 68-69 with or without console? I would like to have the center console.

If you are going to use a tremec or other transmission with the top mounted shifter then you don't really need the shifter tunnel. The tunnel is for the stock type transmission with the shifter mounted on the side of the trans and adds clearance for the shift rods running along the side of the trans.

 

[Molson1802]

Yeah, we haven't decided if we are going to the tremec yet, I would like to, my Dad is wishy washy on it. So might as well just start down the path of a 4 speed swap.

 

[ChargerRTguy]

My opinion in doing the swap, the 4 speed would be the easiest to do, no mods or hacking up the car is needed. Except cutting the hole for the 4 speed hump. All the drive line parts are readily available. I used mostly all used original parts for my swap. I have not regretted it, it's soo much more fun to drive than the auto. I saved the trans and all the parts, so it could be converted back in the future.

 

[Wijns07]

I love my four speed car...but if you have a built motor...be prepared for a violent drive....

Not for the faint of heart...

 

[Boise68]

I love my four speed car...but if you have a built motor...be prepared for a violent drive....

Not for the faint of heart...

Not sure what you mean....please enlighten. Thanks

 

[Molson1802]

I love my four speed car...but if you have a built motor...be prepared for a violent drive....

Not for the faint of heart...

Just a 440 with 400hp, 500lb-ft torque.

 

[ChargerRTguy]

Mine has similar hp and torque, drives fine. Would depend on the rear end ratio also, i'm using an 8 3/4, 3.23 ratio, there is 3.55, 4.10 etc. The type of shifter might make some difference, most use the Hurst setup. I got a good deal on a complete Inland setup, rods in excellent condition and have had no issues. Some of the early '68's had Inlands before they switched to Hurst. Late '68-'69 used the Hurst with the walnut shifter knob, in '70 all used the Hurst pistol grip shifter.

 

[Molson1802]

Mine has similar hp and torque, drives fine. Would depend on the rear end ratio also, i'm using an 8 3/4, 3.23 ratio, there is 3.55, 4.10 etc. The type of shifter might make some difference, most use the Hurst setup. I got a good deal on a complete Inland setup, rods in excellent condition and have had no issues. Some of the early '68's had Inlands before they switched to Hurst. Late '68-'69 used the Hurst with the walnut shifter knob, in '70 all used the Hurst pistol grip shifter.

Yeah, I haven't even really gotten to the linkage part yet. In the process of rebuilding the diff and front end. I have a 489 sure grip(originally a 742 open diff) going in. Probably going to reuse the axles, the splines match. Sticking with the 11" x 2.5" rear drums for now. Too bad Dr.Diff doesn't have a full diff kit. You can get the gasket kit and axle bearing kit. But you end up with duplicate gaskets. Probably going to keep the stock bearings, no green bearings.

 

[ChargerRTguy]

Sounds like you are making progress. I am using the original power drum brakes, I rebuilt the whole system. Since I have had no issues with the diff, never needed to rebuild it. In the near future there is a company that makes metallic brake shoes and heavy duty parts specifically for drum brakes, I might look into it. If you need any drawings or more info on the conversion, I will try to help.