I'm trying to understand the best possible scenario for initial timing for my '85 351W, but I can't seem to make it all make sense in my head.

Here's my setup:

Stock block with E7 heads. All smog stuff was already stripped off when I bought the truck (F-150) last summer. Previous owner replaced the distributor with a P.O.S. AutoZone unit, the cap wobbles no matter how many caps I've tried with it. EGR pipes exiting out from the back of the heads were cut short and crimped over. Air pump removed. Accessory vacuum system was in shambles. Stock intake with Holley 600CFM carb.

Engine seems to be in good shape, even with the above problems. Uses NO oil, coolant looks great, no leaks anywhere.

So here's what I wanted to do. Finish up the removal of the now nonfunctional smog system, plug the back of the heads where the EGR stuff attach, replace the dist with a ProComp 7000 series dist /w vacuum advance and it's matching "eCoil", and change out the intake with a Performer manifold.

I do most of my driving in the low RPM ranges. All I want is low-end torque. I hardly ever get in the highway, and mostly limit my 55MPH driving to county roads. I'm using regular gas.

I've read so many opinions on initial timing, I getting confused. Anywhere from 6-15 degrees BTDC. I've also read to open up the spark plug gap to .050-.055

So, where should I start with initial timing? What do I look for to fine tune it from there? What about the plug gap? Any other ideas?

Thanks for any suggestions and/or info!!

Kevin
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Start at 10 degrees base timing. Plug gap should be ~.043".

There's no reason to buy a new ignition, the Duraspark is good for what you're talking about. Just get a new dizzy from NAPA

 

My wife already bought the ProComp dist. last week for my birthday...I bought the Performer for myself this week.

I'll start at 10 degrees, but what do I look for to fine tune it from there? And again, I've read SOOO many opinions on the plug gap....and they usually gravitate toward increasing the gap significantly. Why is that?

 

Increased plug gap is only good if the coil output voltage also increases.. otherwise you will likely create a misfire problem. The basic rule with timing is to give the engine as much as it will tolerate without detonation, keep throwing more at it until you hear audible pinging under load and then back it off a enough to make it stop.

 

Thanks all. I think I have what I need now for my timing question.

Oh, now that my coil is outputting significantly more spark, should I change the plug heat range or anything like that? I'm using 25's right now.

 

10-4 on what Paul said, the theory is that as spark energy increases the plug gap should (or can) increase with it to give the biggest spark/best chance for combustion. Start at .045", drive it, if there's no stumbles then try .05", drive it and check for stumbles, etc.

Just use plain old Motorcraft spark plugs too. Fancy plugs are just a crutch to help disguise the effect of a poorly operating ignition system.

Another trick with timing is to keep advancing it until the engine tries to push back (i.e. cranks slow) when you activate the starter. Then back it down 2 degrees and you should be spot on.

Heat range has nothing to do with spark voltage, use the recommended plugs.

A vacuum gauge is a great diagnostic tool for shade tree tuning, too.

Don't forget to slather the dizzy gear with assembly lube.