61 lwb 24 mpg with a tailwind !

[moporridge]

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Changed the distributor in my Mileage King 318 recently, it started running rough and the culprit was the bushing inside the distributor letting the reluctor core touch the pickup which resulted in shavings. Needless to say I was gradually losing performance and mileage. I had a few old mopar electronic distributors laying around in pieces from which I'd robbed this or that through the years. I gathered up the junk I had and built one with adjustable vacuum advance and found an advance plate with a much smaller slots than the other 3 that I had. With the new Junk distributor my mileage is back up and just last week with a strong tailwind I got an amazing 24 mpg ! I was getting 18-20 when I first got it together last year. This is with a 68 318, 88 swirlport heads ,Offenhauser spreadbore dual port intake, 450 economaster Holley ,pacesetter headers 1 1/2 from a 96 Ram , running a 2.76 gear at a steady 60 mph. So my theory with the original 68 pistons and shaved swirlports is that I think I have 9.5 to 10:1 comp..... and the shorter advance slots limit my total mechanical advance and the adjustable vacuum advance backed off allowing me to run a bit more initial advance resulting in better mileage. Its amazing how much performance you can get out of a distributor from just understanding how it works and fiddling with it. Of coarse i need to check total timing, intial & mechanical combined but what the heck, parts out of the junkbox, stab it and feel the timing with it revved up a bit for total advance and then see how she starts once shes warmed up, that did the trick for now.

[elacruze]

I've seen over 20mpg on mine, 318, 4speed and 3.55 gears. I converted to electronic ignition and set initial timing so I can force it to ping on 89 octane, then I run premium (or non-ethanol when I go by that station) IIRC my total timing is 34* + whatever the vacuum advance adds.