I have an older 850 DP on my car and I am going to try and lean my transfer slot (idle feed restriction) circuit a small amount and I think I may just use a small piece of wire as this carb has no jets other then main jets. Yes I could modify it but I want to try the wire in the idle restriction to see how it works. But I am not sure how the wire effects it compared to changing the idle restriction jets on newer carbs. So I was wondering if anyone has done this as I know its an older trick and I was curious what size wire anyone who has done this started with. Thanks , Ron

Do you have a numbered drill bit set that will measure the I.D. of that hole? If so see what size it is now and try and reduce the hole size by 1/4 to 1/2 of what is is now with a small wire, maybe one strand off of a wire brush or wire wheel
I started reducing the idle fuel feed and transition fuel feed holes in the Holley Dominator carbs. I use by drilling and tapping those holes for a number 6 brass set screw and then reducing the OEM hole size by a little les than half the I.D., that really helped clean up the AFR at low part throtlle cruise RPMs Before that I had used a small piece of wire in the idle air bleeds to clean up the idle and slow idle speed crusing, that helped also

You need to know the size you now have like Cab said to determine how much smaller to go BUT there`s a change needed to the idle bleeds to keep the %`s the same.............

roughly what is the ratio of bleed to IFR that we should be looking for?

also, does the idle bleed size affect any timing of circuits like the MAB does?

Don`t have exact ratios on bleed to ifr`s as every motor`s different but on my carb I was at .070 ib and .039 ifr`s and went to .067 ib`s and .037 ifr`s and cleaned it up nicely and got rid of a slight lean spot off idle. A smaller bleed provides fuel further in the throttle opening than a larger one and will maintain a signal at a larger throttle opening than the larger bleed. Large=signal sooner.............

thanks thumper.

Thanks for the replies everyone. Ron

Any time..............

Ron..
Are U aware that the Quick Fuel Technology metering plates actually have idle restrictor jets..
More $ but far more precise..

Just my $0.02...

When you can I agree go billet although you still need to drill n tap the ifr`s into the lower position, clean up emulsion etc. but you can do that w/stock blocks as well............

Yes I know but since cash is tight for me right now I thought I would try this old trick and see how it works. And thanks , Ron