Finally got a tach hooked up in the tilted T, and find I'm running about 2300 at 60mph. Without having done any research yet, anybody have an estimate on upper rpm limit for sustained highway driving?

Roger

My brother's 83 Dodge shorty van with 3.2 rear gears runs about 2500-2700 at 60-70 MPH on the highway. It can do that all day long.

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Casually looking for a Clifford hyperpak intake for cheap.

If rebuilt properly with good parts and your carb mix and timing are worked out I don't see 4K as anything to sneeze about...Stock engine that has been well taken care of and the bearings and tolerances are good, I think 3K should be more than fine for hours of driving if needed...

I would think 2300 @ 60 is about perfect.

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Yeah....Im the one who destroyed this rare, vintage automobile.....

hi sages- how about 1800rpm at 60 in a featha dusta with a 2.9 rear and a .73 od 4th yielding a final drive of 2.14. actually pumped 33mpg on the hwy. only way to beat that would be if you transplanted in one of those 2.45 rears, but not sure it would run with that. sounds like too much gear. anybody ever do it? regards bob f

OK, guys.....thanks. Maybe it's just that the engine is hangin' out there in the breeze, and I can hear everything, that makes me think I'm winding it a bit tight.

Neglected to mention that the rear has 3:08 gears, and the car weighs in, in the neighborhood of 1500-1600. (Haven't actually had it on scales yet.)

Roger

I used to cruise my 64 Dart all the time at 34-3500, including CA to OH to WI and back. Stock type rebuild, but balanced bottom end. It would get about 20 MPG (904, 80 MPH). Now it's more like 23-26 MPG with the 5psd and 2.46 final drive in 5th.

Lou

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Home of Slant6-powered fun machines since 1988

I have 3.55 rear gear, run at 3000 rpm @ 60 mph. 70 mph is 3500 rpm, and it runs fine at 3000 to 3500 rpm for 70 to 80 mile stretches of interstate driving, being about the longest rides I make with that car. Translation I don't have the need to travel over 100 miles very often.

What I have noticed since running at Maine's recently reposting of speed limits on I-95, 70 mph south of me, and 75 mph north of me, is the engine consumes more oil; about one quart per 1000 miles. I attribute this to PCV system sucking some oil from valve cover, and not poor oil ring or valve seal problems. Previous to running car at higher rpm, driving at or below 3000 rpm it would get 1500 to 2000 miles before a quart was added.

Years ago I had a night job making snow 6 pm to 6 am at a nearby ski slope, and water for said activity was pumped about a 1/4th mile from a stream utilizing a propane fueled slant six powered water pump which ran continuous twelve hour cycles night after night at around 4000 rpm. To my ear at the time it sounded like it was red lined within its protective small pump shack and about to blow its top, but the thing never missed a beat.

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67' Dart GT Convertible; the old Chrysler Corp.
82' LeBaron Convertible; the new Chrysler Corp
07' 300 C AWD; Now by Fiat, the old new Chrysler LLC

Yeah, these engines are just loud. Especially if you've got an exhaust leak under the hood from a bad manifold or flange seal.

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Somehow I ended up owning three 1964 slant six A-bodies. I race one of them.
Escape Velocity Racing