Well, I finally pulled the Slant from my '60 Dart to start on my first re-build.

I have a good idea of what I want to do to it based on what I have learned from all of you here on the Forum, but would like some more input specific to my car and motor.

First of all, this is what I have:

225 Slant, Carter 1bbl
904 Push Button
7 1/4 Rearend (I haven't checked personally, but I read that 3.23 gears were the standard ratio for 1960 7 1/4 rearends). Can anyone confirm?

What I plan on doing is:

Having "the works" done to the head (ported, oversize valves installed with hardened seats, milled with a min. goal of 9:1 compression).
Installing a larger cam
Offy 2X1 intake
Dutra duals
Electrinic ignition

I'm not looking for a race engine, just a little more power...keep in mind that this is a 3200lb car. And I would like to keep the current tranny and the rearend, at least at this time.

My questions are these:

Since I have the motor out, should I go ahead and bore the cylinders? The motor was well taken care of and only has 120K on it. I'm going to check the compression this weekend, but it does run smooth.

Suggestions on cam size?

What about rearend gear ratios? I mostly drive this around town on a regular basis, but a few time a month I drive it to work, which is a 40 mile highway drive, one way. Currently, it's a chore to keep it at 55/65 on the highway.

I talked to my mechanic and he said the head work would be no problem. What info should I provide to him? Should I have any cylinder work done ahead of time so that he can determine how much to mill off the head?

Also, I believe at one time I saw a chart, here, that told how much to mill the head based on cylinder bore and the compression that you wanted to have. I tried a search but couldn't find. Anybody recall this?

Again, thanks for any and all input.

Bill

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Bill

'60 Dodge Dart Pioneer

Vivian

After you have it apart, I'd check the bores. If they need to be bored, then I'd probably go 60 over. If they don't need to be bored, I'd leave well enough alone.
I like my 270 Erson.
3.23's sound ideal for your intended build and usage.
This table does exist, but isn't terribly accurate because stock chamber sizes differed by so much. The ideal way to do it would be to get the bottom end built, and then measure the deck height. From there, you will need to measure the existing chambers and determine how much material needs to be removed to get you where you want to be.

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Used to own:
'82 Dodge D150
Erson 270 Cam, O/S valves, mild port work, ~9.5:1 compression

Currently fighting with an '85 VW Cabriolet

My other passion

Explane why it a chore to keep it at 55 or 65 on the highway i doint understand that statement rpms or what. Thanks Ron Parker












It Aint Over Until I Win

Ron,

Yeah, exactly. Seems like the RPMs are somewhat high at highway speeds. I didn't mean to make it sound like anything major, just noticable.

I assume that this is normal since it is such a heavy car and takes a bit to keep it moving along.

Thanks!

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Bill

'60 Dodge Dart Pioneer

Vivian

Have your mechanic check-out this ebay SL6 head for some ideas on what to do to make a performace Slant Six head.

You will need to measure the bores to see how much taper is in them, more then .007 and the cylinders should be rebored and fitted with new pistons.
DD

Available ratios in the 7¼" rear in '60 were 3.23, 3.55, 3.91. But, are you quite certain you've got a 7¼" rear axle? I'm away from my office (and manuals) right now, but I am fairly certain the 7¼" was used only in the Valiant in '60, with the larger cars (e.g. Dart) getting an early 8¼" design that is of no relation to the familiar '73+ 8¼".

You're getting good feedback already in this thread. I'm curious: What's your overall goal for the car? How do you intend to use it? Reason I ask is that if you're not trying for high-RPM zoot, there's little reason to put in oversize valves. The stock-size valves are plenty adequate for mild builds, and their relatively small size improves low-RPM engine characteristics by keeping port gas velocities up. Increasing the compression a little is a fine idea, but be careful not to go too high, or you'll get pinging and have to buy expensive high-test gasoline. The "twin breathing" in and out (Offy 5041 and Dutra Duals) should make a nice combo that is period-correct for the car. Pay careful attention to the distributor advance curve, because a lot of power, driveability and economy can be found by making sure this is just right. Think carefully about camshaft selection; it's very easy to buy too much camshaft and kill your low-end torque and economy in exchange for high-RPM breathing you'll never use. Me, I distrust the Comp 252° cam, and I like the 244° Mopar Performance cam (no longer available from Mopar, but Doctor Dodge's cam guy can grind it). DD also has done extensive experimentation with cam grinds and so is a good guy to talk to about a cam for your particular purpose.
As has been advised: Check their condition carefully. You may need anything from just a light surface hone to break the glaze, to an overbore.
Please explain. What makes it a "chore"? These cars in the stock configuration don't have a problem keeping up with traffic at 75 mph once they reach that speed, unless something is the matter. Optimal final-drive gear selection is dependent on several factors, not least of which is tire size.
Careful there, too. Porting is more an art than a science. I certainly don't know how to do it beyond just easy/obvious cleanup of casting lines. It's easy to do more harm than good with a die grinder!
Well, you'll want to measure the combustion chamber volume on the actual head you'll be using, so that you can determine how much to mill off the head (or, maybe preferably, the block!) to attain your desired compression ratio. There's no magic number, because the CC volume varies greatly from head to head. If you are going to put the effort and money into building up a head, see if you can without too much hassle start with a '68-'74 head, which has a somewhat better-shaped combustion chamber. The difference is minor, though, so don't feel you have to go to great lengths to do so.
See above, such charts are useless because of CC volume variation.

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

In the end...my goal is more performance, a nice exhaust sound, and a unique looking motor that goes with the Forward Look era body. It is basically a hobby/project car that I plan on driving on a regular basis, but not as a daily driver to/from work. Also, maybe a cruise night or car show now and then.

Clear as mud, right?

I have thought about just cleaning the motor up, hitting it with a nice coat of paint, and going with the 2x1 intake and the Dutra Duals, along with a MP 244 cam (from DD's cam guy, possibly?), and a shave to increase compression, and not even mess with the internals (as long as they check out OK). Why fix what's not broken?
But then again, that's part of the fun.
No, I'm not certain of that. I'll have to look in my service manual. Though, I thought that they had a chapter on the 7 1/4" rear end. Let me know if you find any info on this, if you think of it. Thanks!
Interesting, I hadn't thought of that. Good to know.

Noted. I'll make sure to have this checked.


Thanks All!

Now, if I can just make a decision. There's just too many fun things to do with/to the Slant 6.

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Bill

'60 Dodge Dart Pioneer

Vivian

The "clean it up, maybe mill it a little, new valve stem seals, MP244 cam, 2x1 intake, electronic ignition and the Dutra Duals, drive and enjoy" idea has a lot of merit to it. You could certainly check the timing chain for slack, and of course you'd want to do whatever gaskets are leaking and/or particularly easily accessible during this work, but beware of feature creep! It's usually less costly, more fun (car back on the road quicker) and much less hassle to plan-out a "next round" of upgrades than it is to go back and undo something you did 'cause you got carried away with all the fun stuff that's out there to buy/install.

Feature creep usually leaves you sad, frustrated, poor and, in extreme cases, unable to drive or enjoy your car. Been there and done that, too many times. It doesn't always work out that way, see e.g. here. But unless you have an awesome shop and a big bank account...ya gotta watch out for feature creep or it'll bite you in the tuchus!

Make a plan...stick to it...and let other ideas and other projects wait for other plans.

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

My Chrysler parts catalog for 1960 states that 8 1/4 and 8 3/4 rear ends were used intermittenly in production.

- If the diff carrier has 1828 448 on outside, it should be the 8 1/4
- If the diff carrier has 1820 657 on outside, it should be the 8 3/4

Additionally, I'll bet with a driver and fluids, you'll probably weigh in near 4000#'s.

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Cheers!
Al T

"Feature Creep"

That's a good one Dan, only because I know that I'm guilty. I'm constantly trying to reel myself in and think practical about what I should, or shouldn't do, to my Slant.
You make a some real good points. I'll have to sit down tonight and come up with a plan...and stick to it.

Al:

Thanks for the info on the rear end size. I'll have to crawl under there tonight and look for the number.


Did Chrysler make a Sure-Grip for any of those sizes that year? If so, are they still available from anyone?

oops! there I go "feature creeping" again.

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Bill

'60 Dodge Dart Pioneer

Vivian

Sure-Grip, yes, butchya don't need it and it's very expensive. Spend less on better tires and wind up happier.

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

As I suspected, you guys got it right, Al and Dan.

Buried in a chart in my service manual, it says that I have an 8 1/4" differential with 2.93 gears.

Missed that the first time I perused through that chapter.

Thanks again, everyone, for your input and advice!

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Bill

'60 Dodge Dart Pioneer

Vivian

I would agree that your car most likely has a 8 1/4 but based on your comment that the engine seems "pretty busy" at highway speeds, I would guess that it may have a 3.31 gear ratio. Time to get under the car with a wire brush to see if you can find a ratio tag hanging off one of the center section nuts.

The good news is that the 8 1/4 housing is the same as the early 8 3/4, the bad news, these have a funky taper axle set-up that is hard to work on.
DD