That’s a loooong post. I think I said before you NEED power valves on the primary side. And IIRC you said the carb builder said to not use them. Either way, they need to be in there and set the opening at 2 numbers lower than cruise RPM.
The second thing I notice is it looks like all 5 emulsion holes are open. There is no way that will work properly. You need 3 MAX and they need to be in the .024 range if you are going to use 3 emulsion.
Why are the carbs 3 circuit? With all the emulsion (and even when/if you correct that) you don’t need 3 circuits. Unless you have HUGE carbs on a small engine or you are using an oxygenated fuel or you are using E85 or methanol.
You didn’t mention idle feed restriction sizing. Are the IFR’s at the bottom of the metering block or at the top? They should be in the lower position. What size are the idle air bleeds? All those things matter. Or Power Valve Channel restriction sizing.
What size is the Main Air Bleed?
I could be wrong but those carbs need some work. You need to pin all those holes and write them down and post them here so we can see exactly what the tune up is.
This is where “Holleyitis” comes from. That thing should drive like a dream but it won’t with no power valves, emulsion that causes “slugging” which you are seeing in your wildly fluctuating A/F readings and that idiotic 3rd circuit.
Of course, these are just my opinions so take them for what you paid for them.
What a freaking shame.
EDIT: I just read your post again. If the 3rd circuit air bleed is blanked (no hole) then you do NOT have a 3rd circuit and that’s a damned good thing.
All the rest of my post is accurate. I’m just glad you don’t have a 3 circuit carb. That makes this way easier and cheaper to unscrew.
EDIT II: I just went back through this thread a few pages and saw pictures of these carbs. I forgot they have down leg boosters. I even mentioned that annular boosters are probably a better choice.
That said, you have what you have and you’ll probably need a SKOSH more emulsion with down leg booster than you would with annular boosters but certainly not all 5 emulsion holes open.
Hopefully that’s my last edit…
With and without power valves it drives pretty much the same.
Carbs came with 76 iab and I also tried using 64, 82, 86 to see what happens. Wanted to get more turns on mixture screws hoping to stabilize the idle.
I will take better photos of the metering block, but it seems 3 of 5 holes are functional. There are no restrictors down low, only on the top and there is a restrictor in main body.
These metering blocks are used by BLP with power valves as they are in their weekend warrior carburetors.
This is it:
BLP Fixed emulsion 3-circuit metering block BLP Fixed emulsion metering block [ 51701B-5R-FE ] - $53.95 : BLP, Xtreme Performance Made In USA
I really don’t know why they are 3 circuit. This is how they were built. Before I bought them I asked the builder if I can street drive with them, he said yes but I assume it’s my English that’s the problem because I heard they were built for racing last time we talked.
I used his advice regarding setting them up.
I know you suggested annular boosters but I think only TMC uses them. BLP, APD, Bigs, Thumper all use downleg which makes things more difficult especially where I am. My access to parts is not existent, all needs to be imported half way across the world with 3 weeks of waiting minimum and I’m taxed to oblivion. 1500$ carb bought in USA becomes 2400$ carburetor after shipping and taxes.
I jumped on these, because with used stuff you sometimes can avoid import tax and I lucked out this time.
I figured if they are essentially BLP I can change all I need in the process to of making them work well on my car.
Also frankly these are expensive carbs so I expected more effort put into metering blocks. I didn’t expect practically off shelf stuff used.
Now I need to either get tapped blocks and set them up with good advice of someone experienced or order finished blocks from someone knowledgeable. I like working on my stuff but every mistake delays this thing working well for another 3 weeks…
I went thru so much crap because of this car that’s sometimes I think how do I still go on with this. I’m literally hated by most neighbors because of noise and smell. Would be nice if the thing at least run good enough to make me not give a damn about all the enemies I made having it here.
I’m sure it can work well eventually but I hoped for something better especially after asking the builder about them before money changed hands.
The good thing is power, I really see that once I setup this stuff right, the car will work much better.
