Update: Saturday I pulled the IAB's and found out they were .072 not the .078 that I had written down. I now remember doing that, but for the life of me can't remember if i actually tested afterwards. Then i went and broke the ever so important rule. I changed more than 1 thing at a time.
#1 Seeing that i used to run my vac advance with manifold vac i went back to that but left the fast curve in it,
#2 i put .070 IAB's in, adjusted mixture and idle, so the tune for most recent test is this:
P/S
.031 IFR .031
.070 IAB .070
.085 TSR .080
.046 PVR -
.036 MAB .036
74 main 80
10.5 PV
Emulsion stack from the top:
1) .028
2) blocked
3) .028
4) blocked
20* Idle timing 34* all in at 2300rpm and 14* of vacuum advance @ 15" of vac. vacuum can starts to add @ 6" of vacuum.
The results:
MPH RPM AFR VAC
35 1500 14 15"
45 1850 15 16"
55 2250 15.5 16"
65 2800 15 16"
70 3000 15 15.5"
Now there wasn't a big change but it was much better sounding and feeling. No longer feels flat in that transition area. The only negative thing was a popping out of the exhaust from say 40-60mph. I suspect that the timing is coming in too fast and is almost maxed out at 50mph. my next test will be to slow the curve back down and retest. It's definitely much better by the ear and butt dyno.
Sunday I slowed the advance curve by changing springs in the dist. I was unable to graph the curve at the time due to being by myself. Took it for a spin and the “popping” is all but gone and she’s running well. Smooth from idle to any cruise speed and stable at any cruise speed. Hopefully the weather mellows out this weekend and I can get some help graphing the timing curve. Probably put some fresh plugs in it and test some more. So far the butt dyno results are encouraging.
