After a couple of years with my 1850's, I have decided to give some Holley center squirters a try on my tunnel ram. I rebuilt both to factory specs and have them on the car. On the initial start, it is definitely rich. I am about 2 turns out on the idle mixture, but I am thinking I am going to have to place some restriction (wire) in the idle circuit to get it leaned out enough. The factory main jetting is 76, and I am leaning toward going down a few steps but am curious what others have done with them.

I've got about 6 lbs of pressure on them and it is idling around 1k. This a race only 451-10.89/123 mph.

They should lean out fine, mine did anyway

Are you planning on putting wires in the idle air bleeds on the top of the main body or the idle fuel restrictors in the metering blocks, if yourmetering blocks have them? If in the idle bleeds the wires will reduce the holes and make it run richer at idle, not lean it out. If you want to reduce the amount of fuel at idle and the mixture screws won't reduce it enough try opening the idle bleeds up say .002, .004 and then .006 a little at a time until you get it the way you want it I have a set of 660 C.S. that I bought that I haven't used yet, they have been modifioed with metering blocks on the secondary side so you can change jets instead of the metering plates like they came with stock. I'm thinking of converting them to four corner idle also to see if that will help control the idle mixtures better I'll probally run them they way they are first and then decide if they need fine tuning and modifications or not

I'll put the wire in the idle fuel restrictor in the block. I will likely try Grumpy's recommendation and use a .017 wire to start. Like I said before I am also considering leaning out the main jetting from the stock 76 setting. I am hoping that by reducing the mains to maybe 73 and inserting the wire, I can tune from there with the idle mixture. The secondary plate are basically 73, so basically I would have them all square. Quick Fuel makes a modified secondary plate that accepts jets, so I may go that route if necessary before going to a full block in the back because if I go full block I will have turn them sideways and I would rather not have to deal with the linkage unless I have to.

Thats a lot of CFM.....

Where is it fat at... idle or top end

I ran a pair of them inline. I used only one to idle on. Both had .018" wires in the slots in the blocks.
Also ground some of the secondary cam off to retard opening of the secondaries. I didn't have a really good converter.
This is old school, but it worked for me 30 years ago.
My

They dont respond much to jet changes for some reason, sounds funny but true. The last set I had didnt respond very well to most any changes, like jetting..
So far I believe they run best with the factory settings, jets, restrictors etc.
I picked these carbs up for a a few hundred bucks last winter, I took ten apart and blow out the holes, thrown on some used gaskets on them turned the idle mixture screws out abut 1 3/4 - 2 turns.
They idle very nice, they will come around even better with some more tuning. and set the timing on the engine..
No stumbles or flat spots.
BTW
These will be for sale some time later on when I get the car sorted out some.

I used to run 660's on my last race Hemi, they were a pain to get to run consistant, sent them to Chuck Nuytten to have them "matched" and they became the best carbs I ever ran. never had to futz with them and my ET were very consistant.

It is fat at idle, it blackened up the plugs in just a few minutes of run time, so I was a little concerned it might load up pretty badly just driving through the pits and in the staging lanes. I have heard that this has been a problem for others.

If you have to idle up enough to get into the idle transfer slot, the idle mixture is rich enough that the idle mixture screw cannot completely correct it, thus the need to reduce the fuel via the wire in the idle restriction hole.

I have also heard the same that they are not extremely reponsive to jet changes and that there is not a lot of tuning to perform on them. As someone has already said also, they tend to run better in near stock form.

Where did most of you wind up on main jetting? Grumpy's book stated that you should be able to find a home somewhere between 69-75.