What kind of mileage does your Cadillac get?

[35-709]

"Hasn't someone here got a 500 in a Lasalle with and OD trans and he said it didn't help that much?"

I have rebuilt 1971 472 in my 1935 Cadillac, MTS #10 cam, Sanderson headers, 700R4 trans, otherwise stock with the Q-jet.  I drive it at turnpike speeds and do a fair amount of traveling with it.  It gets about 2 MPG better than my stock '73 Caribou, MTS-built stock 472, and rebuilt Turbo 400.
I might have been the one that said that it didn't help enough to warrant replacing the TH 400 with a 700R4 (or 200-4R) on a '70s Cadillac considering the expense and modifications required to do the job.  Since I was starting fresh with the '35 the 700R4 was the only way to go, IMO.

["Cadillac Kid" Greg Surfas 15364]

Chris,
With a "high compression" motor and a #10 cam you should get at least as good a mileage as what the original combination got./  That of course depending upon how many of the horsepower you use, and for how long.  Fuel consumption is just about .48 pounds/horsepower/hour. That works out (if you use 100 HP for one hour at say 80 MPH) to 48 pounds or 8 gallons per hour for 60 miles. That's 10MPG.  Just a mathematical calculation.  I used to get somewhere around 16 MPG at 70 MPH cruise in my 70 CDV. Again, It really depends upon the state of tune and how aggressive your right foot wants to be.
Greg Surfas

[The Tassie Devil(le)]

. How many of us check the oil on every fill up with a new car less than a few years old?

I remember the days when one could set the fuel filler onto the first click of the ratchet, and then go and check the oil and other stuff under the hood whilst the tank was being filled.

These days, all the ratchets have been removed from the handles which make us have to stand there and operate the filling till the tank is filled.

Try and then do other things to the car and you will soon get "told" to move the car to give others in line the chance to fill up.

Bruce.

[Jeff Rosansky CLC #28373]

I would drive home from college in my old Montego.....90 miles or so.  I would take every tool I owned, extra parts, water and oil.  Even had a CB at the time.  Now, I would hop in the Honda and drive cross country without even checking the oil.  My times have changed..... By the way, I had to get gas in the Motego before I could drive the 90 miles back. 
Jeff

[savemy67]

Chris,

I donated my lead foot to Exxon Mobil many years ago.  I would consider your mileage on the low side so I would suspect that your engine is not yet dialed-in, or your combination of aftermarket parts is not conducive to economy, or you still have your lead foot.  You might want to experiment with a vacuum gauge and tachometer to see if changes in driving habits affect your mileage.  Adjusting your foot while using the vac and tach, and trying to keep vacuum levels as high as possible, can reveal a lot about how you drive as well as how the car is operating.

Christopher Winter