Driveline options

[Jon M]

65 Polara 383/ 727
Hey all, looking to improve the drivability of my car for more highway driving.
Current setup is all factory, 8.75 rear, power drum brakes.
I’ve looked into converting to a manual trans but parts are hard to come by.
Auto options are just as pricy or far more fab work than I’m capable of.
My father in law suggested I put steeper gears in the rear for power rpm and a higher stall on the trans to help off line acceleration.
Anyone ever done this? Combos that work?

 

[Polara_500]

Gears are easy, maybe a 3.23 for off the line oomph yet highway friendly. The converter issue is harder as the input splines on the 65 transmission are different than later ones and ...... you guessed it........ they don't make many options for the earlier ones. Of course you can rebuild your transmission and update it to play nicely with the later torque converters, but it do add $$ to the mix.

 

[CBODY67]

383 2bbl w/2.76 rear axle ratio and 215/75R-14 tire size? Which should be about 27.5mph/1000rpm in 3rd gear, on the road. Should have the 252/252/.390" lift cam, same as the 383/315 4bbl that model year.

With that rear axle ratio and tire size (equivalent), the torque peak is about 85+ mph, which means it's about where it needs to be to cruise with current Interstate traffic (75-85mph, by observation) easily.

If it still has the original distributor, and a 2bbl, the advance curve is pretty much where it needs to be, but might be quickened a bit.

One of the easiest, least expensive things you can do to make the car feel happier in normal driving . . . BUT some in here might disapprove of . . . was suggested to me by an old-line Chrysler service manager at our local dealership. He'd done it to his personal '67 Newport 2bbl and I did it to the '66 Newport I was driving at the time. Which caused NO issues with durabilty, due to the fact that it's a small change. What is it?? Remove the kickdown linkage from the carb pin, then ADD 2 more turns of preload into the linkage (lengthening it slightly). Then put the rod back on the carb pin. What that will do is raise the min and part-throttle upshift speeds in "D" about 3-5mph. More acceleration with less throttle input. The car will feel happier when accelerating as the after-shift rpm will be a bit higher than it used to be. Min throttle 2-3 upshift should be about 29mph with the 2.76 gears and 24mph with 3.23 gears. It's worked well for me with NO transmission durability issues on the '66 or the other TF727s I own that I've done similar with. Try it and see. If you don't like it, it's easy enough to put back like it was.

Other than that, another 2.5 degrees BTDC added to the base ignition timing spec. Ensure the carb's accel pump is working well. 30psi in the tires won't hurt either.

In the "spend money" aspect, a good 2.25" dual exhaust system with '72 Imperial mufflers should help a bit. A new quality timing chain is "cheap insurance" for engine longevity. Then an Edelbrock Performer intake and 600-650cfm carb of choice. Some good HD shocks can make it handle the 75-90mph (natural) cruising speed on the road, too.

Make it run as good as it can, right now. It'll NEVER compete with newer 4cyls with an 8-speed automatic (and their 4.50 low gear ratios!) car, so don't even try to do it. Unless you want to swap to a GM THM700 automatic w/OD and complement that with a 3.55 or 3.91 rear axle ratio. Which also might need a Sure Grip addition to the rear axle, too.

Just some obervations and experiences,
CBODY67

 

[Big_John]

65 Polara 383/ 727
Hey all, looking to improve the drivability of my car for more highway driving.
Current setup is all factory, 8.75 rear, power drum brakes.
I’ve looked into converting to a manual trans but parts are hard to come by.
Auto options are just as pricy or far more fab work than I’m capable of.
My father in law suggested I put steeper gears in the rear for power rpm and a higher stall on the trans to help off line acceleration.
Anyone ever done this? Combos that work?

Sorry, but this isn't making a lot of sense here.

You want to "improve the drivability of my car for more highway driving", and then you talk about "steeper gears in the rear for power rpm and a higher stall on the trans to help off line acceleration"

Pick one.

You haven't said what engine is in the car. 4bbl or 2bbl. That's kind of the first thing that would help.

Never listen to your father in law. I've had three of them (just 2 wives though). All of them were idiots when it came to cars, so I expect that is how they all are.

 

[cbarge]

I'm with Big John on this one.
Are you trying to make a car with 57 year old technology act like a newer car?
It can happen with loads of unlimited funds.

All I can share is what I did to my car to make it street and highway friendly.
Add part throttle kickdown to your trans valvebody. This little mod makes a huge difference. Trans will shift better be more effecient and reduces wear. Also the engine will not lug and eliminates the need to manually downshift when accelerating down an interstate on ramps and when climbing hills
I am running 2.94 gears and a 28 inch tall 23570r15 tire.
I am Running a Comp cam 268H which is the limit for stock convertor (though works best with a 2200/2500 stall)
The cam and part throttle kickdown combined I dont really NEED a stall convertor as when I need to accelerate it down shifts on its own and the engine is in its "powerband "
I get 15.4 MPG all day long running at 65-70 MPH. Plus a joy to drive in around town.

 

[Jon M]

First off, really appreciate the input.
Car is a 4bbl Edlebrock AFB.
Big John, pretty sure I didn’t word correctly. I do trust my father in law but he’s more familiar with GM stuff. I never got to know my first 2 fils. Lol
By steep gears, I mean numerically lower. Higher stall was to compensate for the sluggish take off.
Do I have any options with my carb like what was described?

 

[Big_John]

First off, really appreciate the input.
Car is a 4bbl Edlebrock AFB.
Big John, pretty sure I didn’t word correctly. I do trust my father in law but he’s more familiar with GM stuff. I never got to know my first 2 fils. Lol
By steep gears, I mean numerically lower. Higher stall was to compensate for the sluggish take off.
Do I have any options with my carb like what was described?

OK, now we've got something to start with.

I wouldn't mess with the convertor. You've got a heavy car and the loose (high stall) convertor isn't where you want to head.

I assume that the car also has a dual exhaust. If not, that's a really good addition.

The part throttle down shift is a great option, although there's some more work involved with the '65 trans as you need to marry the later valvebody with the older cable shift valve body. I just did it on my '65 Barracuda and it's great, but getting the cable adjusted again was a bit of a nightmare, so it's not as simple as the later cars. It isn't so much the procedure as it is dealing with the 65 year old cables that have worn into their happy places.

What you can do is some simple stuff... First, get everything running right. That's huge. So many cars that need "mods" to make them go fast will get their tails whipped by a stock car that's just tuned right. Your 383 Polara isn't going to be a rocket ship, but it should move alone OK. Does the secondaries open all the way on the carb (for example) Still running points? When is the last time they got attention or the plugs?

You can also wake the car up a bit with some distributor recurving. If you do that, you might as well convert it to a more trouble free electronic.

Lots of things like that... Once you open Pandora's box of mods, it gets crazy and suddenly the car isn't any fun to work on or drive, so you need to proceed cautiously.

 

[Jon M]

Wow I had no idea the potential started with the carb.
Yes it does have dual exhaust. 2.5 through glasspacks.
I’ve wanted to convert to electronic ignition but haven’t had any luck finding anything.
Tell me more about the valvebody.

 

[cbarge]

I’ve wanted to convert to electronic ignition but haven’t had any luck finding anything.

Summit Racing has a complete electronic conversion kit that includes a nicely recurved distributor.
Works well in my 383..
1965 DODGE POLARA Proform Parts 66993 Proform Electronic Distributors | Summit Racing

 

[cbarge]

Ok,when you go electronic,with your 2.5 exhaust and 4bbl carb you will have to fine tune everything.
Advance the timing more than stock,fatten the mixture or change metering rods or jets.
Factory specs go out the window.

 

[70bigblockdodge]

Tuning and timing chain will produce amazing results.

 

[Big_John]

Wow I had no idea the potential started with the carb.
Yes it does have dual exhaust. 2.5 through glasspacks.
I’ve wanted to convert to electronic ignition but haven’t had any luck finding anything.
Tell me more about the valvebody.

Get everything right first and the ignition as recommended is a decent choice.

The part throttle valve body allows the car to downshift without pressing the accelerator to the floor. I've done it to both my '70 300 and my '65 Barracuda and it's great for me, especially because I live in very hilly country side. It became standard in Chrysler products around 1973(?) or so.

From 1966 up, it's a straight forward mod. You pull the valve body in the trans and add the pieces, bolt it all back in and you're done. For a 1965 car, like yours, it's more involved. The 1965 trans is cable shifted and now to do this mod, you remove the valve body, and use the upper pieces from a later valve body. It's not rocket surgery, but it does involve getting deeper into it, removing and replacing some of the "guts" and that can be a little intimidating to someone who hasn't messed with this stuff.

Then there's the reinstallation in the '65... It all bolts back together, but I had problems getting the cable adjusted right. It took me several tries and I'll blame it on cable wear. Finally, Mrs. Big John sat in the car and worked the shifter (should have done this to begin with) and I figured it out. It all works great now, but keep a couple things in mind, I've done a transmission or two, and I have a lift in my garage. In other words, would I recommend this mod? Yes. Would I recommend this mod be done by a guy that's never done it, laying on his back in his driveway on a '65? Ummm... Not so much. Would any trans shop be able to do this mod? Probably not. Got to be someone that knows these cars.

 

[Jon M]

Tuning and timing chain will produce amazing results.

I don’t believe my engine has been rebuilt. New timing chain?

 

[Jon M]

Get everything right first and the ignition as recommended is a decent choice.

The part throttle valve body allows the car to downshift without pressing the accelerator to the floor. I've done it to both my '70 300 and my '65 Barracuda and it's great for me, especially because I live in very hilly country side. It became standard in Chrysler products around 1973(?) or so.

From 1966 up, it's a straight forward mod. You pull the valve body in the trans and add the pieces, bolt it all back in and you're done. For a 1965 car, like yours, it's more involved. The 1965 trans is cable shifted and now to do this mod, you remove the valve body, and use the upper pieces from a later valve body. It's not rocket surgery, but it does involve getting deeper into it, removing and replacing some of the "guts" and that can be a little intimidating to someone who hasn't messed with this stuff.

Then there's the reinstallation in the '65... It all bolts back together, but I had problems getting the cable adjusted right. It took me several tries and I'll blame it on cable wear. Finally, Mrs. Big John sat in the car and worked the shifter (should have done this to begin with) and I figured it out. It all works great now, but keep a couple things in mind, I've done a transmission or two, and I have a lift in my garage. In other words, would I recommend this mod? Yes. Would I recommend this mod be done by a guy that's never done it, laying on his back in his driveway on a '65? Ummm... Not so much. Would any trans shop be able to do this mod? Probably not. Got to be someone that knows these cars.

Ok do I need to find a later valve body or is there a source for one? I know some Mopar folks who should be able to make the swap. I definitely agree about not doing it on my back although I’m really curious about seeing the transformation.

 

[Jon M]

Ok,when you go electronic,with your 2.5 exhaust and 4bbl carb you will have to fine tune everything.
Advance the timing more than stock,fatten the mixture or change metering rods or jets.
Factory specs go out the window.

The carb is set up great now. No flat spots, crisp response. I really hate to mess with it but will do it in the name of improvements.

 

[Jon M]

OK, now we've got something to start with.

I wouldn't mess with the convertor. You've got a heavy car and the loose (high stall) convertor isn't where you want to head.

I assume that the car also has a dual exhaust. If not, that's a really good addition.

The part throttle down shift is a great option, although there's some more work involved with the '65 trans as you need to marry the later valvebody with the older cable shift valve body. I just did it on my '65 Barracuda and it's great, but getting the cable adjusted again was a bit of a nightmare, so it's not as simple as the later cars. It isn't so much the procedure as it is dealing with the 65 year old cables that have worn into their happy places.

What you can do is some simple stuff... First, get everything running right. That's huge. So many cars that need "mods" to make them go fast will get their tails whipped by a stock car that's just tuned right. Your 383 Polara isn't going to be a rocket ship, but it should move alone OK. Does the secondaries open all the way on the carb (for example) Still running points? When is the last time they got attention or the plugs?

You can also wake the car up a bit with some distributor recurving. If you do that, you might as well convert it to a more trouble free electronic.

Lots of things like that... Once you open Pandora's box of mods, it gets crazy and suddenly the car isn't any fun to work on or drive, so you need to proceed cautiously.

On the exhaust, would it benefit from an X pipe or H pipe? No difference? Reason I ask is I happen to have the X pipe section left over from an earlier project that never made it on.

 

[cbarge]

The carb is set up great now. No flat spots, crisp response. I really hate to mess with it but will do it in the name of improvements.

Once you do the upgrades you want, the engine will tell you what it needs.

I am speaking from my own experiences.
Going with electronic ignition you may or may not experience a lean condition.
You carb may be perfect now but will need adjusting afterwards. Maybe an extra shot from accelerator pump--- but listen to the engine. Use and read the vacuum gauge, timing light, and read the spark plugs and she will tell you what she wants.
Hope this helps.

 

[cbarge]

On the exhaust, would it benefit from an X pipe or H pipe? No difference? Reason I ask is I happen to have the X pipe section left over from an earlier project that never made it on.

Any H or X pipe will help balance the scavenging of the exhaust producing a nice even tone. The most obvious difference is it will be quieter at cruising speeds.
Two of the main reasons why I use TTI C body systems for example.
Cheers.

 

[Jon M]

Once you do the upgrades you want, the engine will tell you what it needs.

I am speaking from my own experiences.
Going with electronic ignition you may or may not experience a lean condition.
You carb may be perfect now but will need adjusting afterwards. Maybe an extra shot from accelerator pump--- but listen to the engine. Use and read the vacuum gauge, timing light, and read the spark plugs and she will tell you what she wants.
Hope this helps.

Yes, thank you. Been a minute since I’ve messed with all that on these old cars but I can get familiar again.

 

[bnz84]

On the exhaust, would it benefit from an X pipe or H pipe? No difference? Reason I ask is I happen to have the X pipe section left over from an earlier project that never made it on.

I have an H on 3" pipes and it immediately took the drone down at 35-40mpg on up. At 55 its almost quiet, I can talk to the person next to me with the top down. But below ~35 I still have some work to do - likely need some resonators or Magnaflows instead of Flowmaster. Anyway there is much debate over H vs X with most modern cars going with X. But the guy I was working with (has the welder) has worked on a variety of older V8s suggested H. If you have highway drone I think you appreciate it.