4spd to auto conversion

[fasttrax91]

I want to swap out the 4 spd in my 440 powered 68 for an automatic, what do you guys recommend, and what stall converter is best for the street...   does any one have list of parts i'll need for my conversion

thanks

[cudaken]

 Fasttrax91, we will need details on the car. Cam sizes, rear gear's, street car or race. One thing I will tell you, to much stall on the street will make the car feel slower. Take's longer for the converter to spool up unless you power brake the car.

I have a mild cam 461 and 480 lift in my 69 Charger and run a 400 police converter and 2.76 sure grip gears. Work's very well, gives me around 2400 stall.

Welcome to the site as well.

                                      Cuda Ken

[fasttrax91]

Fasttrax91, we will need details on the car. Cam sizes, rear gear's, street car or race. One thing I will tell you, to much stall on the street will make the car feel slower. Take's longer for the converter to spool up unless you power brake the car.

I have a mild cam 461 and 480 lift in my 69 Charger and run a 400 police converter and 2.76 sure grip gears. Work's very well, gives me around 2400 stall.

Welcome to the site as well.

                                                        Cuda Ken

thanks cuda ken...
the motor was just rebuilt (.030 over bore) to stock specs....
the car will see mostly street duty with the occasional romp at the track.. i don't know what's in the rear but i plan on installing a new posi / locker unit and 4:10  gears for that seat of the pants feel 

[Troy]

I know you'll need cooling lines to the radiator, a different trans crossmember (and possibly mount but they may be the same in 68), and kickdown linkage. The driveshaft should be the same length. You can buy a nice new trans from places like TCI and they can recommend a converter to go with your combo. It will help if you provide the rear tire size as well. If you go with 4.10s I really hope you don't do a lot of highway driving.

Troy

[max]

If you go with 4.10s I really hope you don't do a lot of highway driving.

Troy

i have to agree with that. i have always like the 3.55 ratio for the street.

a local fellow that i know bought a 440 powered 1967 GTX a few years back and it had 3.23 gears and an automatic. he wanted to step it up as well and he asked me what i would use and i told him the same, use a 3.55 set up and it would work great.

well he worked for an auto parts store and i guess he thought i didn't know what i was talking about so he bought a 3.91 set and had it installed. 4 months later he had them removed and went back to the 3.23's and told me later that he wished he had listened to me.
sometimes we have to learn the hard way though, and i'm just as guilty

[Ghoste]

I have 4:10's and they're fine for highway driving.  You just can't do a lot of "high speed" highway driving. 

[cudaken]

 Fasttrax91, the converter I told you about would be great. But again, more details, is it a steel crank or a cast crank? 74 Polices converter is a cast crank converter, with out knocking off the counter weight you will shake your teeth out and waste your mains as well.

I personal think 4:10's is to much gear and will slow down in the quater mile. Engine will fall out of it's power band to quickly.

If you post the height of your tires top to bottom on the car and will do the math for you.

3.55's or 3.71's would be better.

                                      Cuda Ken 

[fasttrax91]

Fasttrax91, the converter I told you about would be great. But again, more details, is it a steel crank or a cast crank? 74 Polices converter is a cast crank converter, with out knocking off the counter weight you will shake your teeth out and waste your mains as well.

I personal think 4:10's is to much gear and will slow down in the quater mile. Engine will fall out of it's power band to quickly.

If you post the height of your tires top to bottom on the car and will do the math for you.

3.55's or 3.71's would be better.

                                                        Cuda Ken  

I'm going to try to fit  275/40/18 out back for street use and 28x10.5 slick for the track... the crank is steel
thanks for all of the advise
 

[cudaken]

 Fasttrax91, here is some figuers for you with 4.10's. On the street tires I need to know how tall they are, I have no idea how tall  275/40/18 are.

At 3500 RPM's with 28" tall tires you will be doing 71 MPH.

At 100 MPH with 28" tall tires you will be spinning 4920 RPM's.

A pure stock 440 will live at 5500 RPM's for a while but will be hurting the Rod bolts. Peak HP is at 5200 RPM's.

Here is the math with 3.55's and 28" tall tire.

At 3500 RPM's 82 MPH

At 100 MPH 4260 RPM's.

My self, I like playing on the interstate. My 69 Charger has PR 265 R 60 15's and are 25 " tall. I run 2.76 sure gripp rear end. At 100 MPH I am turning a whole 3709 RPM's. You see me on the interstate, not the places to want to play with me. Poor guy in a W-30 Olds found that out the hard way.

                         Cuda Ken