My latest Toy: A dodge AT4 with a difference

My 1939 Oldsmobile, weighing in at more than two tons, with a 307 Chev V8 running fuel injection heads and a 600 cfm aluminium 4 barrel, used to return 20mpg towing a caravan - and that was with a crappy old two speed powerglide! Used to upset a lot of the other caravan types at the time with their 351 Fairlanes, and the like, running anywhere from 12 - 18 mpg. :pinch:

Reckon you'll romp it in.

Hi PDU
Crappy old powerglide is a bit harsh unless I had a freak.Powerglide behind a 186 in a HD Premier had to really flog it to get worse than 25 mpg 30/32 on a trip and the trips were never what you’d call steady

I did a quick calculation.

The rear tyres are 235/60r14 which gives a diameter of 25.1 inches or 638mm according to this site
tyre size calculator

The diff ratio is 2.75

I plugged the data into this RPM calculator
and it came up with 2347 rpm at 100kmh.

as an Exercise i put the XP tyres of 185/70r13 tyres into the calculators
it gave a diameter of 23.2 inches (589mm). it's diff is 4:1 giving 3600rpm at 100km and I know flat out is 107kmh at 3853rpm

The comfortable cruise on the XP is around 80kmh is 2881 rpm or roughly 500rpm more than the dodge will be doing at 100km. at 80kmh the dodge will be 1878rpm.

Of course the dodge is 400kg heavier at 1600kg while the XP is around 1200kg.

I know from experience that our AU Falcon with it's 4 litre 4 speed auto chewed about 1litre/100km more than our manual 5 speed 2 litre Mondeo. However a 6x4 trailer on the drawbar put the AU 1litre/100km in front as it didn't change consumption as the Falcon didn't notice it while the Mondeo did. The heavier the trailer the more it swung in favour of the AU. It is possible we may see something similar between the Dodge and the XP. Time will tell.

Back on the powerglides I thought they had a reputation of being bullet proof. For many years they were the gearbox of choice in drag cars

Still used in Drag Racing but not too many stock parts in them.

Interesting point is only the Aussie built Powerglides had removable bellhousings.

The ones made in the States were one piece construction.

Power glide where good for lots of adapted uses take the torque converter of and plumber around using the pump for drive and shifter

They were known as "Power Slides" when I was a boy.

I didn't mind the powerglides but those Hydramatics were the worst They went slow then slower.

Any automatic on the back of a grey motor is going to be slow.....!

Jarrod.

They were very brave for trying it.

Normally would have to agree on the Hydromatic but did see an EJ many moons ago that went like the clappers. No idea if it had been play with but it was a surprise.