MDchanic

Sorry I've even got to ask this, but I don't have any multi-make reference books this late, so I can't confirm it myself.

My "new" '73 Delta convertible has a 260 in it from somewhere between 1977 and 1981. It was set really retarded (as it were) compared to its spec., and runs better now that I've advanced it.

HOWEVER, I have found two (and only two) references to this spec on the web - one says the timing should be set to 20 deg BTDC at 1,100 RPM, the other says it should be 20 deg at 500 RPM.
This is important because the mechanical advance activates before 1,100, and adds at least 4 or 5 degrees between 500 and 1,100 RPM (don't know if it should or if it's got weak springs).

So, if anyone out there has this info in a reliable reference, I'd be grateful.

Thanks,

- Eric

olds 307 and 403

20 at idle is fine. What retard stuck a 260 in that car? I will race you on foot, should be a close one. Get a 455 in there or a 403 at least.

MDchanic

I have no idea, but I doubt he planned to keep the car very long.

The price was right, so I'm not complaining.

As for the 455, having owned a '68 Delta and a '68 98 with high compression 455's, and having felt the acute pain in my wallet that only 6 mpg can bring, I have to say that I'll stick with the 260 for now. I may not be winning any road (or foot) races, but at least I'll be able to roll slowly past the gas station .

Thanks a lot for the response! I'll go out and advance it a few more degrees. When I got it, the thing was set to 12 deg, as specified for 1973, with a non-functional vacuum advance, and, man, was it a joke to drive! New advance unit should come in the mail in a few days, and then I'll try driving it again.

- Eric

olds 307 and 403

A 403 will lose maybe a couple of miles to the gallon but has over 300 ft/lbs of torque stock. I get over 20 mpg with mine, no comparing to a 260. Of course you know that.

MDchanic

I'm impressed by that.

With both my 455's, which I used as everyday drivers and commuters in different years in the '90's, I got 6 mpg, 4 if I was having too much fun.

I'm not even kidding.

And for comparison, the cars were 4-doors, 1 98 at 4,400 lbs and 1 88 at 4,100 lbs, both, if I recall, with 2:56 rears. I believe the motors were rated (pre-1971 system) at about 365hp and 500ft/lbs.

If you're getting over 20 with a 403, either the characteristics of the motor are very different (mixture, cam, ?), or your car's much lighter, or there's some other voodoo I'm just not getting.

If I could have gotten anywhere near that mileage, I would never have sold that 88, but on a 70 mile round trip commute, it was absolutely killing me on gas, and I couldn't keep it just lying around without using it, especially since it wasn't an antique yet, and registration and insurance costs were more than I could afford on a car I couldn't use (in addition, at the time, to my '70 911, '72 Skylark Convertible, and 2 motorcycles... ).

- Eric

olds 307 and 403

My Quadrajet is border line lean and my car weighs just under 3700 pounds. I went up to a 3.42 and with the 2004r I run at 2000 rpm at 60 mph. It actually runs at less rpm than the 2.56's due to the lock up always engaging. 8.3 to 1 performer cam, intake, Sanderson shorty headers and 2.5": duals with a X pipe. About a 2000 stall converter and a no slip in the rear end. Will spin the tires from a roll and go snaky due to the no slip. With drag radials and tuning, expecting low-mid 9's in the 1/8. 10 flat in the 1/8, so far with fuel starvation and traction issues.