I'd save your money and just tap the blocks you have. Its not hard.
Timing is at 19 initial. I didn't have a buddy with me so i can't check when it all comes in.
You should be able to do this without a helper (even though its always nice to have one). However a tachometer is crucial.
If it is 19 at idle, but idle is 950 rpm, then its still possible the initial base timing is 14 degrees. Here's the issue; its not a biggy but it can make it a little more difficult to get a consistant idle. When the car is warming up or put in gear the engine slows a little, to say 800 rpm. Then if the timing drops off with rpm, at 800 rpm it is only 16 BTDC.
To check the curve without a helper, use the idle speed screw to open the throttle. That way you can read the timing and rpm, write it down, then open the throttle a little more. I try to record every degree or every 200 or 250 rpm. It really is whatever is easiest with what you're working with.
I adjusted all 4 idle mixture screws until they were out just under one turn. They were out around 1 1/2 turns. Idle speed did pick up some so i was able to back off the idle speed screw.
Good.
At 900 RPM my afr gauge says 12.5 or so in park. When I put it in drive it goes to 13.5.
Vacuum is still around 15 at idle.
If what you're seeing on the AFR gage is real, it is due to the engine rpm slowing from the slight increase in load. As mentioned above, lower rpm *might* be accompanied with less advance. It almost certainly is also losing a bit of manifold vacuum. Think about what happens when there is less vacuum (pressure difference) across the idle circuit with no other changes. So that's probably why you're seeing that on the AFR gage.
My idle air bleeds out of the box are .025. Right now I have .027 for all four. I have .030 available that I can put in if it might help.
Check that. Those seem small for idle (except two corner idle secondaries). Those sizes are more like Main Air Bleeds, at least for the 4150/60s I've worked with.
I know it sounds like a pain, but be sure the primary side t-slot relationship is ballpark correct before making changes to the bleeds. Have you read yet that the T-slots are an air bleed too? So if that t-slot to throttle blade relationship is changed after changing the idle airbleeds, you will almost certainly have to change the bleeds again.
When it comes to larger air bleeds or smaller IFR, you'll probably have to experiment methodically. Just remember a larger bleed can sometimes cause the fuel to start moving earlier, making it richer when you expected it to be leaner. Vizzard's books and the posts at Racing Fuel Systems will help with that.
As a few others said above, idle circuit tuning is important but time consuming.
I haven't pulled the plugs out lately but the last time i did they were black.
Try to clean 'em. When the AFRs are looking better, definately get a clean set in.
