New arrival at the BBM-stash, and an exception to my #1 rule... '73 Dodge Dart

[Scott Liggett]

You forgot the fluids running up your arm and into the armpit. I hate that.

[BigBlockMopar]

I thought I would show some progress I've been making on the car after some time has past since the last updates.

I bought and installed a Hellwig swaybar a while back already, because my car didn't come with one at all. Because of the lack of swaybar driving around in the rain wasn't always safe when taking corners and such. Taking a corner on wet streets should be taken very carefully because the nose of the car would dive in considerably, and because of that the rear end would loose traction and just slide out or way oversteer the car.
With the swaybar installed the car feels and is much safer again.




This weekend I will be installing larger 11.75" discbrake rotors from a fullsize Chrysler.
The Dart currently has just about 11" rotors, but they're getting thinner. Also the calipers are rusty inside and 1 of them already became stuck recently. I was able to get it going again by taking it apart and lightly sand the inside and piston, but I don't think it will last very long anymore.
With the larger rotors already on the shelves I just had to buy new calipers and new hoses. I will also use larger caliper brackets from a '77 Dodge Charger.
Another reason for the upgrade upfront is that the current brake-bias of the car is at the rear axle. Since I've upgraded the rearaxle to a 8-3/4" rear end (with larger brakecylinders), the rear wheels tend to lock up earlier than the fronts.
I'm hoping with the larger C-body rotors the front brakes will outbrake the rears again. Otherwise I still need to install an adj. prop. valve.

Mock up...



Lately I've also been trying to get some more decent mileage from the car.
Ever since I've had an Innovate AFR gauge in the car, I've been able to increase the mileage from a lousy 8mpg to a current 15.5mpg by tuning the propane fuelsystem and ignition.
I've modified a stock aircleaner housing in which I incorporated the propane mixer-unit, so I can fab a coldair intake for it.





Today I've also changed the oil. In trying to get some more mileage I went from a 10w40 with some ATF mixed in, to a synthetic blend 5w30 oil.
On the way home I didn't notice a obvious change in oilpressure yet. While cruising the pressure is still 60psi, and warm idle in Drive is still between 30-40 psi. With colder autumn-temps coming soon, I'm tempted to even replenish the oil with 5w20 and some zinc-additive to keep the cam alive.





Next item on the list is the installation of an A518 overdrive transmission.
I hope it doesn't turn out to be another 14 hour pull in the garage, as the crossmember has to altered considerably in the car for this transmission to fit...




Oh, and I also blew some cash at a MegaSquirt-box, ignition driverboxes and propane injection-stuff for the upcoming 5.7 Hemi engine-transplant in the Dart...

[Huskinhano]

Cool stuff but will the 518 live behind the Hemi? Looks like there is a lot of USA stuff available over there?

The price of natural gas has fallen tremendously over here in the last couple of years with the Marcellus shale gas field, I'd be interested in looking at a conversion

[TheSilverBuick]

Looking good! Nice mpg upgrade!

[BigBlockMopar]

We have a fairly large market for US carparts overhere with numerous of partssuppliers and some speedshops scattered around the country. That's mainly because older cars over 25 years are exempt from roadtax.
But most of the stuff I get comes directly from the States. I try to do my part in supporting the US-economy, while our local economy is flushed away to Greece.

The a518 transmission isn't a bad design in itself, as it's based on the earlier bigblock-727 transmission, which was a stout transmission.
I've learned the main problem with the 518 is a possible lack of cooling when the overdrive is in use. But with a large enough dedicated radiator it will live. Also I've read somewhere about a small modification to aid oilflow to a bearing by enlarging an oilfeed in the output-shaft.

A gas is a much nicer fuel for an engine than vaporized gasoline because it can't fall out of suspension in the intake during it's way to the intake valve. Therefore a gas-engine can run much nicer at a slower idle speed. The fact that LPG costs half the price of gasoline overhere helps aswell. :o)

[BigBlockMopar]

Finished the discbrake upgrade saturday. The car brakes nicely, but I need to increase the MC-diameter as the new calipers have a larger diameter.
The brakepedal has a fairly large travel now.

[BigBlockMopar]

Exchanged the master cylinder today for a larger aluminium one I had laying around. The old MC had a 15/16" diameter. The new one has 1-1/32" diameter. Brakepedal and force feels good again.

It's starting to look more and more like a proper car now





Up next is getting 'myself' ready for the transmission-swap.
The driveshaft tunnel needs modifying (grinding/welding, some denting aswell maybe), along with that I need to replace 2 freezeplugs at the rear of the engine. One of them is seeping some drops of coolant every now and then.
Also the driveshaft needs shortening 'again'. Same as last time, I will do this myself as I want to try to get the car running again that same day and be able to take it home.

[BigBlockMopar]

Well a couple of months later I was finally mentally ready to start with the transmission-swap.
I went from a 904 to an A518 transmission. The A518 is a 'bigblock'-transmission with a smallblock bellhousing and overdrive. Later tranny's also have a lockup-function, but mine didn't have that. This means I can use a regular '60s stall convertor.

Because a 518-transmission is more bulky than the 904, some considerable modifications are needed in the car like the driveshaft-tunnel and rear transmission crossmember. This is because these overdrive transmissions weren't available on these cars and years yet.


Pic of the removed 904-transmission, which had developed some slow 2-3 shifting issues;




Pic of the 518 waiting patiently;







The top half of the transmission-crossmember had to be completely removed, otherwise the transmission couldn't be mounted high enough in the car.
The 518-transmission also come stock with a deep oilpan, so to keep enough ground-clearance, a proper transmission height was mandatory.




To restore proper stiffness, the top of the crossmember will be welded from inside the car later on.

The bottom half of the crossmember was modified to accept a simple Chevy mount which I happen to have laying around in the garage.




After a lot of trialfittings with the transmission, it was finally time to install it properly.
It was then time to renew the coolerlines, as these transmissions have 3/8-lines, as opposed to 5/16 used by the 904.
Then it became apparent the stock speedometercable had become too short now, so a new, longer one was ordered.

With connecting the 'kickdown'-linkage, I had to lengthen it about an inch to get the proper travel again.

Also the console-shifter linkage had some issues now.
Because of the bulky body of the transmission, the linkage could not go straightdown through the tunnel anymore. But with a slight tilt of the linkage I managed to get alongside the transmission again. Another small modification was done before I was finally able to shift through all the gearsettings again.


Finally it was time to shorten the driveshaft (again). I had shortened it before when I swapped the rearaxles.
The 518 is about 5.5" longer then the 904. So out came the pipecutter again.
After measuring twice, I cut the driveshaft also twice :o)
I cleaned up the yoke on the lathe and tapped it back into in the driveshaft tube again, were, after some slight correctional taps, it was welded into place again.




All this was done a week ago.
My main concern was to get the car drivable again as soon as possible.
So I've only just managed to (electrically) get the overdrive unit working when I found a suitable plug.
I rigged up a simple switch on the console where I can (for the time being) control the overdrive myself.

I must say it was a pleasure feeling that overdrive-unit kick in for the first time during driving in this car. Also because I didn't know anything about this transmission other than the PO said it should work alright.

Even with the 2.94 gearratio in the rearaxle, turning on the overdrive at cruisingspeeds above 35-45 mph makes for a nice and quiet driving car.
The motor doesn't turn a lot of rpm's anymore at these speeds, so getting on the throttle is not advised ofcourse.

It was a lot of work, but seeing how much it has improved the ride-quality of the car, it was well worth it.

[BigBlockMopar]

Yesterday I decided it was time for the front of the car, to meet the rear of the car, and persuade them to do the same movements together when driving.

So, I cobbled up a set of subframe connectors and welded them in place under the car.

The difference is very obvious. The car feels much more rigid and sounds more solid, and quiter aswell.
Also the front suspension is more noticable now in the car, especially the springs feel like the have just a tad more springload.

Anyway, I'm quite happy I took the step to fab up a set, for next to nothing in costs.