>How are you gonna fit a 29" tire on a 65Dart? Does that even work?
To fit a 29 on 67 up will require the axle to be moved back.jus saying
>It only requires in the range of 40 to 50hp to push your 65 thru the air at 65 mph. It's up to you to set your cruise speed at the lowest rpm that the engine makes just enough power, at a modest throttle opening This is easier done with a tiny single barrel or better yet a 2bbl with two venturies.
1) Do a tune-up on the engine including a compression test and a slightly baggy valve lash; say .013/.023 at say 60*F ambient degrees. Make sure the numbers are even. Make sure the Vcan is working. Install new plugs and prove the rest. Make sure the engine runs over 180*F. Check that your exhaust back-pressure is less than 4psi at your cruising speed, going down the road in top gear. Less than 3 is better.
2) Gear the car with the lowest number gear you can find to a minimum of 2.76s. Install "normal-sized" radial tires on it. Like say 27s or thereabouts, and put some extra air in them.
3) drop the nose under the K-member about 1 inch, from level at the rockers.That is to say; level the rockers, then drop the nose one inch.
4) install a dash-mounted, dial-back, timing retard box, with a range of at least 15 degrees. With 27" tires and 2.76s, 65 will be 2230 at zeroslip, perhaps 2350 on the tach. Your engine will be wanting a ton of cruise timing, perhaps as much as 50* at 2350. Your D will be hard pressed to deliver say 30* which will send your fuel economy plummeting. With the dial back, you can almost give her what she wants.
5) Get the car up to cruising speed, then lean out the cruse until it starts bucking or won't hold a steady speed, and then put a lil fuel back in. Now, on flat, level, hard ground, with no wind or hills, get her up to speed again, then read your speed-O, and write it down. Then with the Dial-back, add about 5 degrees, (guessing is fine) continue driving and watching the Speed-O. If the speed increases, slow the car down back to the starting point. Wait for the speed to stabilize. Then add another 3 to 5 degrees, guessing is still fine. and watch the speed-O. Repeat until the car no longer increases in speed, or you run out of timing adjustment.
If at any time, the speed of the car does not increase with the addition of timing, back the dial up to the last time it did, then get her back up to cruise speed, and wait for the speed to stabilize. Finally check the rpm and write it down. Pull over and put a timing light on it. Rev it up to the recorded rpm, and read the timing; write it down. Jump in the car, back up the dial back to zero and go home.
What this does is find the exact right timing for the chosen roadspeed and load. Now you just have to build your distributor as close to that as possible, and later during the trip, dial in the rest with the DB tool. The trick is to remember to dial it out, whenever you lay on the gaspedal!
Now you can go back and finish futzing with the carb.
6) if you make any changes to the load or the cruise rpm, you gotta start over.
No other tricks will come close to, in fact I would venture to say that All other tricks together, will not reap the benefits of exactly correct cruise timing.
Factory timing can be incredibly conservative; don't be surprised to see only 10/12* in the Vcan. You may need to get the basic power-timing worked out first. Typically, the Vcan has less than 12 degrees in it. You can grind off the stops to get more but I think it tops out at around 22/24. If you put in much less than 2.76 gears your engine may not have enough vacuum to pull it all in. In which case the change may bring negative results. IMO 2.76s is the lowest I would go. Cruising at 2350 for fuel-economy is very doable.
Here is what I do with SBMs; How it may translate to slanty's I cannot say.
Put a vacuum gauge on the intake. In neutral slowly rev the engine up . watch the vacuum. when the vacuum reaches it's highest, for fuel-economy in a given combo, that is your lowest cruise rpm.
Now Tee the vacuum gauge onto the spark port. Roadtest it in top gear. Begin at 1800rpm or so. Slowly increase your speed. When the vacuum reaches it's highest level at steady speed, that is the highest cruise rpm, that you should consider...... because after that your cruise timing MAY begin to drop out.
Happy HotRodding.
my '68 took me over 3000 in 9 days last summer. I've done numerous 1000 mile weekends with absolutely no problems whatsoever.
I had to replace the original starter while on the trip and fought a clutch that didn't like to disengage after 50 miles of driving. That ended up being a bad transmission input shaft pilot bushing. I've had friends that wouldn't go on a road trip without a trunk full of parts that are available at any NAPA store. I did throw in a basic toolbox that came in handy for that starter replacement.
