Quote:

Exactly
I understand "why" its rich. This is where a carb. with metering rods wins! More gear and or a looser converter would let me drive past the trouble spot. I`ll get as claose as I can then move on.



Good deal!

I'm fighting the same problem as you are... or I was fighting before I (in your words) got as close as I could and moved on.

In my case, I'm definitely cruising on the t-slots, and this is a bad deal... impossible to tune. I also have a wider vacuum difference between idle and cruise than you do, making my situation worse than yours.

So, at the risk of telling you what you already know:


"Close" for me was the following: large PMABs, as-small-as-possible IFRs, and I'm using t-slot restrictors, but IIRC they're fairly large (not much restriction).

I have a stock primary metering block with 2 emulsion bleeds in the "classic Holley" location... I have the primary float level set below the level of the top e-bleed. A better fix would be to buy one of those pretty billet metering blocks and move the top e-bleed above the "normal" float level position. This is an attempt to get the main circuit working at lower venturi airflow, and it works, just not well enough.

I have another baseplate with shorter t-slots, same width as stock... some circle track piece I snagged from eBay. I briefly tried that, and it helped the rich cruise situation, but unrelated problems made me switch it back to the stock one, but there is definitely some potential for improvement there if you can find a similar baseplate with shorter t-slots.

Do everything within your power to increase idle vacuum. One of the easiest ways to get a carb tuned better is to minimize the difference between idle vacuum and cruise vacuum. If the idle vacuum is higher, you can further reduce the IFR size and maybe use smaller TSRs before the dreaded off-idle lean spot occurs.

I have all my specs and measurements on an Excel spreadsheet that I can share with you if you're interested.

Good luck with it.

Jim