Timing curve for my big-cam 451?
In a word... success :D
Today I received the 18/9 cam plate...decided to take the old 26/13 and weld up its slots on the inside, and grind them back out to .390 length. Unfortunately when I put it together, it was obvious that there was too much preload on the (gold) spring and not enough slot left before the OEM heavy loop spring engaged.:p
So I put the 18 deg plate in, as noted with one gold spring and one heavy loop spring, reinstalled the 8L can (16 deg max), and fired 'er up. It works great and is stable (although choppy as usual). 24 deg initial, 37 total and it maybe loses 1 degree during a rev to 4500. With the vac can connected and adjustment full CW, idle is 34 deg and almost 9" of vacuum. Rev in neutral to about 52 deg. Idle mixture on the AFR meter is almost half a point leaner. May have to tweak that a bit too. It's imperative not to put any load at all below 1100 rpm or it drops and stalls.
Took it out for a quick low-speed test (up to 40 mph) and immediately noticed a great improvement in off-idle and part-throttle response. No pinging anywhere, although it would be hard to hear over the 3" X-pipe dual exhaust. Will have to take a close look at my plugs after a highway run, but shouldn't have pinging there either. :)