Car: '70 Dart, 225 super six, auto

The longer I own this car and get used to how it drives, the more I am able to notice how the various improvements (or changes from stock if you prefer) have changed it's performance (for the better). Overall though, I still am having a hard time figuring out what a really dialed in, reasonably stock slant should perform like.

I have noticed that when I am driving on the highway and already going 55 or so, if I floor the gas say to pass someone, I get nothing but a sound that seems like the engine has more to give but something is holding it back. On the other hand, I can build up continuous acceleration slowly unitl I am going faster than I comfortably want to, at least until I come to a hill. Then, on the hill, no matter how far down I press the gas pedal, it will only give so much.

Are these just symptoms of a three speed transmission and "highway" gears? I know the slant has a low redline, and I have driven stick shift cars my whole life until this one ( so i'm used to being able to downshift at will and run up the RPMs as much as I want), but I can barely even get it up past 3000 rpm even if I manually shift it into a lower gear on a hill, which is not something I feel is a good idea.

What I would like to achieve is a car that is fun off the line, has plenty of power throughout it's RPM range, and can cruise at 21st century highway speeds easily. That's not asking too much for a car built in 1970 is it ?

My winter project is going to be installing a front Dutra manifold and modifying the rear as per the instructions on this site and putting a dual exhaust in, but I fear that that will only go so far and that an OD trans with deeper gears is what I should be thinking of next...

Any thoughts or similar experiences/desires/solutions would be welcome.

I know exactly how you feel (at least I used to). I can't help much, though — I cheated. I skipped the process of getting my combo running right and just bolted on a Super Six and Dutra Duals. Night and day difference. Completely different car — I feel like like it runs the way it always should have.

So, the experts can get your stock combo running at its peak, but if that's not enough, fear not. A 2bbl and Dutras will CERTAINLY accomplish your goals.

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vm

Super Six it and start passing people! Especially if your doing duals! I was shocked how much i gained. Living in Ca everyone drives warp 6 or so and before i got the super six i was on impulse power ( slow). Now i have no problems keeping up and even passing when needed. Oh yea gas mileage got way better too (2-3 mpg improvement).

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63 valiant v200 Wagon 9.5, Schneider cam, E.I. 22 mpg all day

Please tell us more about the upgrades you've already done, and the present configuration of your car. The more detail you can give, the better. What kind of carburetor, what kind of ignition, what size tires, etc.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

What is the rearend gear ratio?
Have you checked the distributor's total mechanical advance?
Your (lack of) performance description sounds like a vehicle with slow or stuck mechanical advance.
DD

He already has super six.

I've got a 71 Dart single barrel auto 225, and mine is completely stock except for the 2.25" exhaust. I've run my engine a but over 4k without much problem, so if yours is stuck around 3k, then I would say it is being choked. If you have a stock exhaust system, that is insufficient for a 2 barrel setup. You would need the recommended 2.25" header pipe, and then after the muffler you can taper it back down to 1 7/8" to keep the exhaust gas velocity if you wish. Mine is 2.25" all the way back.

For example, I helped StephanieBrite77 with her car (65 Dart w/74' 225) and the super six setup. The car ran well with just the stock 1 7/8", but WOW what a difference just going to 2.25" made. With duals ( I want a dutra for the front and stocker for the rear as well) it will make a wonderful difference.

It sounds to me like your exhaust is choking the poor girl down, or youve got a serious dizzy malfunction. (As Mr. Dutra suspects)

~THOR~

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1984 D100 Shorty Custom
Certified Auto Appraiser - RevItUp Classic Appraisals
President - Cherry City Bombers CC
Part of Tyrde-Browne Racing

Thanks for the thoughts and comments. It has a super six but stock exhaust, has a Carter 2bbl, 7.25 rear that howls (have an 8.25 to replace it with but it has 2.71 gears so those will have to go first), tires are 195/75/14 on all four corners, front disc/rear drums...who knows how many miles on the engine, but I doubt it is original to the car. Most work done so far besides the super six has been tune up stuff, valve adjustments, etc. I've never looked at the distributor, but it can't hurt to make sure that is it top form.

A better exhaust system will likely help considerably. Any room in the budget for a set of Dutra Duals? If not, a significant improvement without excessive noise can be had by just putting in a 2¼" headpipe running to a Walker #21206 muffler (one of their premium "Quiet-Flow" types, specced for Chrysler products with the bigger V8s), and a 2" tailpipe.

By all means, now would be a great time to pick up a new electronic distributor and upgrade to HEI. You may also want to review the Tune-up parts and procedural recommendations in this thread.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

I've got a front manifold from Doug last spring and am planning on installing it this winter. I'll look into the dist. upgrade as well.

Not sure, but the rearend is just about shot, so I'll be upgrading tha tas well.

I have always been impressed at how much improvement can be made to an engine just by fine tuning the timing. I would (1) check for timing chain slack, (2) check if your dampener has slipped and is no longer reading TDC correctly, and (3) upgrade to HEI (but keep your stock distributor for the governor, springs, and vac advance). Gap your new plugs to .040 (I like .045) and make sure your timing is set correctly.

Start with that before you go nuts. I always like to get the stock setup working right before changing things. It makes it easier to diagnose problems and figure out what to do next.

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Casually looking for a Clifford hyperpak intake for cheap.

That's exactly what I want to do too. These are all great tips!

Um-uhhh...how's he going to upgrade to HEI and keep his stock (points type) distributor? :shrug: He'll need an electronic distributor, and the "remanufactured" ones from the parts store are junk, so a new one's the best way forward. I do agree he should start with a stock-type electronic distributor, rather than the MP unit with its race-only curve, or something needlessly exotic like a Mallory distributor without a vacuum advance. Is that what you were getting at?

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

Sorry, I guess I didn't make myself clear. He needs to get a electronic ignition distributor, but i recommend swapping the springs, governor, and vacuum advance from his current points distributor to the EI distributor to keep the factory timing advance curve. Once he gets the rest of the motor all dialed in, he can spend the time to play with the advance curve. I was just trying to keep him from installing a distributor out of a vehicle tat has a different advance curve than his stock one.

Actually, I am trying to figure out how to adapt a points distributor to electronic ignition. I bought one of those really nice early 60s points distributors with the oiler for the bearings at a junkyard and I want to convert it to EI. I have the guts of several EI distibutors, I just need to find the time to get out to the garage and futz with it.

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Casually looking for a Clifford hyperpak intake for cheap.

Ah. I'm not sure I'd spend the time and effort to do so (in fact, I'm sure I would not). He could install a new factory stock electronic distributor and have a good working street curve to drive around and eventually modify if he wants. There's nothing sacred about the particular specific curves his particular 1970 distributor (if it's original) has, and since he's swapped in a Super Six he's already altered the overall system such that the distributor originality is a moot point (or set of points! ) Swapping the original parts doesn't address that they are old, and possibly contributing to the current driveability problem.
Just for the oiler...? Why? The oiler was discontinued after '68, and the '69-up distributors work just fine without the oiler. But if you're bound and determined, it's not hard; just turn the distributor lead wire into a slot, replace the breaker plate with a pickup plate, and replace the point cam and governor with a reluctor cam and governor. It looks like Chrysler Australia at one time offered a parts kit to do just that, minus the need for slotting the wire pass-through. Chrysler USA never offered such a kit. The linked kit has no reluctor/governor; that'd need to be bought separately.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.