There have been several threads on vac. advance lately, and since I now have my old rusty truck running, I will be wanting to find out what my combo wants. I have a couple of things that may skew the results some, so at least to me, it will be interesting to see what it wants.
First, my combo:
1967 D100 short stepside, lightened a little.
340 based 414 stroker
ProComp heads with the pushrod holes plugged and redrilled for W2 rockers. 210 cc intake ports, 2.08/ 1.6 valves, 50 degree seats.
Solid Roller 251/256 with 640/640 lift on a 106 installed at 105
11.6:1 compression (My chambers ended up being bigger than expected)
KB ICON flat tops .015 above deck
Felpro 1008 gaskets, so, around .025 quench clearance
Holley W2 Strip Dominator ported to match above heads, also some work in the plenum
727 full manual, 8" converter
4.57 gears , 31" tires, on the street
Now, the parts that are maybe a little different from the norm.
First, the only distributor that I have without shot bushings is an old lean burn (factory locked out) unit. I did add a vac pod to it.
Second, and probably the one most won't like, is my 1 barrel carb. (an old 5000 series Predator) I have done a couple of mods to it, the
best being blocking the outermost holes in the spray bar. This cleaned up the idle mixture a bunch. I am also running a 5 percent
leaner fuel cam
Now the kicker, at least for now. My budget is spent. No choice to change distributors or carb. I lost a lot of parts when we moved. I had a tried and true 750 DP that is now MIA. So, I'll be using what I have.
My goal is some decent drag times, hopefully this year. And, to get good enough mpg to afford to drive the thing. To me that is at least 15 mpg.
The Predator may be hungrier than that though.
So, Vacuum advance will have to be a big part of the equation, and I will try both ported and manifold.
Now, I have some work to do, the Predator has no provisions for either ported or manifold, but I will drill the carb for ported, and my spacer for manifold vacuum.
First, my combo:
1967 D100 short stepside, lightened a little.
340 based 414 stroker
ProComp heads with the pushrod holes plugged and redrilled for W2 rockers. 210 cc intake ports, 2.08/ 1.6 valves, 50 degree seats.
Solid Roller 251/256 with 640/640 lift on a 106 installed at 105
11.6:1 compression (My chambers ended up being bigger than expected)
KB ICON flat tops .015 above deck
Felpro 1008 gaskets, so, around .025 quench clearance
Holley W2 Strip Dominator ported to match above heads, also some work in the plenum
727 full manual, 8" converter
4.57 gears , 31" tires, on the street
Now, the parts that are maybe a little different from the norm.
First, the only distributor that I have without shot bushings is an old lean burn (factory locked out) unit. I did add a vac pod to it.
Second, and probably the one most won't like, is my 1 barrel carb. (an old 5000 series Predator) I have done a couple of mods to it, the
best being blocking the outermost holes in the spray bar. This cleaned up the idle mixture a bunch. I am also running a 5 percent
leaner fuel cam
Now the kicker, at least for now. My budget is spent. No choice to change distributors or carb. I lost a lot of parts when we moved. I had a tried and true 750 DP that is now MIA. So, I'll be using what I have.
My goal is some decent drag times, hopefully this year. And, to get good enough mpg to afford to drive the thing. To me that is at least 15 mpg.
The Predator may be hungrier than that though.
So, Vacuum advance will have to be a big part of the equation, and I will try both ported and manifold.
Now, I have some work to do, the Predator has no provisions for either ported or manifold, but I will drill the carb for ported, and my spacer for manifold vacuum.