Aluminum Slant 6 engine

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vntned said:
In my '64 Dart 170, with the stock 170cuin/3spd manual, 3.23 gear, I'd average 23mpg. When I went to a 4spd OD and 3.55 gear I was averaging 27mpg. Most of my driving is in town too.

Now with a 360/4spd 3.55 I average about 12mpg.
Click to expand...
years ago i got 24 mpg round town and highway in a 66 coronet /6 didn't know gear ratio! this time i know i have a 2.94
 
66fs said:
The funny thing is I have found the opposite is true for mpg. I have always built for dependable power, the unexpected result is much better mpg if driven sanely. Of course you can go too big or race oriented and go the other way. My 170 was a really nice high winding engine producing plenty of power to pull a 4 speed Barracuda along and get great mileage cruising on the highway. I can't remember if I was running the O/D at the time. No experience with the Al block.
Click to expand...
I got 32mpgUs out of an 11.2/1 HO 360,
 
Hyup
Final drive ratio; 3.55 x .71x.78=1.966, 65=1588rpm, and over 185psi cranking pressure.
I used an 1850/ 600Holley, with wires jammed into the idle feed restriction until it wouldn't hardly maintain more than 65, PV left alone, secondaries delayed, and mains downsized, maybe 64s, then cranked in the timing, from the front seat, with the timing gizmo until she reached max mph.
All this done in the weeks leading up to the trip.
Then sat back and cruised it straight South to Minneapolis Mn for the 2004 CarCraft Nationals, about 10 hours.
At destination; pull over,put 750DP back on,lol, return timing to normal, and ripchitforthreedays.
Monday morning, reinstall 600 for return trip, and crank in the cruise-timing.Going home we were lighter cuz we had burned up all the Manitoba 87E10gas,that I had brought along, just in case .
It's not rocket science; it's been said you only need in the neighborhood of 40hp to maintain 65mph.I think the Barracuda might be pretty slippery when lowered, and I had spent some time reducing driveline friction as best as I could.
So going with 40hp@65@1588 rpm, this is theoretical requirement of perhaps; (40x5250)/1588= 149ftlbs. Apparently, my engine makes that,............ probably mostly on the transfers..........or, my chassis has a less than 40hp requirement;
else it woulda slowed down and not have been able to maintain 65.
I give much credit to the mucho cylinder pressure, the minimum coolant temp of 205*F, and and the tuning skills of my mechanic, not to mention the fabulous engine design.
This combo also went 106mph in the qtr, with the 750DP, full exhaust,3.55s, and on 245/60-14 street tires..I again,credit the pressure.
 
There was a guy on Moparts who put a Neon engine in a 64 Dart and was in the 29/30 range. It was actually a pretty interesting build.
 
AJ/FormS said:
Hyup
Final drive ratio; 3.55 x .71x.78=1.966, 65=1588rpm, and over 185psi cranking pressure.
I used an 1850/ 600Holley, with wires jammed into the idle feed restriction until it wouldn't hardly maintain more than 65, PV left alone, secondaries delayed, and mains downsized, maybe 64s, then cranked in the timing, from the front seat, with the timing gizmo until she reached max mph.
All this done in the weeks leading up to the trip.
Then sat back and cruised it straight South to Minneapolis Mn for the 2004 CarCraft Nationals, about 10 hours.
At destination; pull over,put 750DP back on,lol, return timing to normal, and ripchitforthreedays.
Monday morning, reinstall 600 for return trip, and crank in the cruise-timing.Going home we were lighter cuz we had burned up all the Manitoba 87E10gas,that I had brought along, just in case .
It's not rocket science; it's been said you only need in the neighborhood of 40hp to maintain 65mph.I think the Barracuda might be pretty slippery when lowered, and I had spent some time reducing driveline friction as best as I could.
So going with 40hp@65@1588 rpm, this is theoretical requirement of perhaps; (40x5250)/1588= 149ftlbs. Apparently, my engine makes that,............ probably mostly on the transfers..........or, my chassis has a less than 40hp requirement;
else it woulda slowed down and not have been able to maintain 65.
I give much credit to the mucho cylinder pressure, the minimum coolant temp of 205*F, and and the tuning skills of my mechanic, not to mention the fabulous engine design.
This combo also went 106mph in the qtr, with the 750DP, full exhaust,3.55s, and on 245/60-14 street tires..I again,credit the pressure.
Click to expand...

I always went for power, the mpg was an unexpected bonus. Running too lean was what the Factory did. I was never a fan. Ran 160 degree thermostats and 20-50 Racing Oil. I always had High Performance small engines, built very efficiently to get the most horsepower I could, be very driveable, and stone axe reliable.
 
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