Hah ..... my '77 that I recently started messing with in earnest ..... I recently put a new carb on, and today decided to see where it was timed, hadn't timed it "recently" that I could recall.

Crawled underneath and cleaned and marked my lines, years ago I had added a 35 degree mark as well. Unplugged vac line and plugged it and put the light on it. about 10, maybe 11 degrees initial at slow slow idle, and up about 25 degrees total. I was really happy to see the timing mark near rock steady, that timing chain ain't so loose it seems. I think I used a Mr. Gasket advance kit in the distributor back in the '80s, maybe changed the total advance some? It does use up what advance is in the distributor really quick, by 2000 rpm anyway.

Well, in view of how much better the truck has been running since I changed carbs and how much better the steering is with a new drag link, I wanted to try a few more degrees. I was thinking these motors liked nearer 35 than 25 so I decided to settle on about 30 total mech advance.

Got my special wrench out and loosened the hold down bolt and ..... damn distributor was stuck. Seemed welded in place.

I ended up pulling cap and cap adapter and rotor and vac canister off so as to NOT break something. That AC mount wasn't helping. I wiggled, pulled, was afraid I'ld break the housing at times. I sprayed penetrating oil all around the base, let it soak, wiggled more .... no budging that I could see or feel. Good news, shaft was snug with no excess play and air gap was perfect.

Finally I used a small nail puller and wedged a little under neath between the Distributor housing under side and intake and with a little pressure, it popped up 1/8" which was all I had loosened the bolt.

Give it a few twist and turns and she's free now.

Checked the vac diaphram, it's original, and still works like new. No vac leaks.

Re-assymbled and started it and set base timing at 16, checked at higher engine speed, total is about 30-maybe 31 degree now. Reset idle, double checked with light, looks OK ..... hooked up vac line and fine tuned idle which speeded up when I pulled the plug and stuck that vac line back on (manifold vacume, not ported).

Didn't realize my timing was so slow until today, I must have ball parkedit years ago and never checked it. I last had the distributor out in 1991 while swapping heads after burning a valve. I had a spare set rebuilt and new guides and etc as I was building my house and could not let truck set for long. Anyway .... she runs a bit better, good response for a low 8. compression 351M with likely more cam than needed.

Crusie control started working again too .... it hasn't worked in a few years and I thought must have thrown magnet off driveshaft or some other glitch but today while test driviong it I tried it and it works like new? Maybe flipping the switch a few times helped? Maybe it likes the Edelbrock carb better than the Holly?

What total mechanical advance figure do some of you use?

 

I run 12 initial, 26 mechanical, for 38 total, plus 12 vacuum (ported).

 

Thanks! ..... I'm in the ballpark.

I'm thinking that I must have used the spring kit and a limiter of some sort, no where near 26 degrees in the mechanical advance mechanism. I'm only seeing about 15 degrees from initial to full advance with vac plugged. I remember something about a bushing limiting advance? Thought maybe I was recalling a Chevy truck I had before this F-150, but that was 1986.

Since my prior post, I went back and set total at 34 degrees, (well, I was shooting for 35 but when I snugged the bolt back my wrench must have nudged the distributor so I'll leave it there). now initial is very close to 20, I'll call it 19 degrees.

Until I drive it some, I put the vac back on the ported vacume outlet. I am unsure of vac degrees available .... no marks up there but easily between 10-15 degrees aditional.