Vintage Mustang Forums banner

10 degrees or 6

684 Views 4 Replies 2 Participants Last post by  adamg69
I have a 351c 4v, I'm trying to set the timing. I have a mustang repair book that says the timing for a 351c should be set to 6, but other people have told me it should be set to 10 like other fords, suggestions? Thanks, Dave
1 - 5 of 5 Posts
It all depends where it runs best at. That will also depend on the compression ratio, the kind of gas and the cam to name but a few. I have mine set at about 12 deg initial and 31 total using an MSD distributor with the quench heads. If you have the open chamber heads I imagine you could run at 12 initial and about 38 total on premium gas.

69 Sportsroof, 351C, 4spd toploader, Restomod BOSS 429 clone - the one and only (?) 1969 BOSS 351
Toss out the timing light and set to the highest rpm/vaccume at idle. Drive it for a couple of days. If you get any pinging, then back it off a bit.

This will get you seat of the pants performance. There were several post about this on the old forum if you want to do a search.

UCLA (Upper Corner, Lower Alabama)
Thank God it doesn't snow this far south!!!
1965 Convertible, 351W, Tremec, 9", continuous "improvements"
1996 Explorer XLT - daily driver
2000 Taurus - wife's driver
exactly...reason being, the outer ring of the harmonic balancers tend to slip a little bit over the years...therefore the timing marks are most likely not right anymore. Thats why they make timeing tape. Find the REAL TDC and mark it , then apply the timing tape. After that, your method might work better...and I'd go 12-14 degrees...

1970 Fastback, 4V 351C, various colors with black interior
My case of 12 deg initial is true 12 deg, when I put the new balencer on I tapped and inserted a locking stud to make it impossible for the outer ring to slip (I put one either side to keep the balence). This guy should not trust the timing marks as you say and find out if his outer ring has slipped. Timing seems to make more sense when set by ear anyway (keep pushing the initial until you get ping under heavy acceleration then back of a tad).

69 Sportsroof, 351C, 4spd toploader, Restomod BOSS 429 clone - the one and only (?) 1969 BOSS 351
1 - 5 of 5 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.