Ben,
Checked with my parts guy this morning, and YEOW! There is a heated carb spacer made by Clifford, and the 4-bbl model # is 08-1856, but it runs about $100. That may take it out of the running in a hurry!
Steve

 

Provided you are running an intake with the heat crossover, it should be enough....assuming that your riser is not effectively insulating the carb from the heat...which the betters ones are designed to do. It does sound like you are in a cold part of the country though...which means that carb needs the heat. I thought powervalve because it sounds like its continously rich...good for wide open, bad for low end. They will idle with a bad powervalve but you should be able to smell it at the exhuast. If you have an electric choke and live in a cold part of the country it will do the same thing though. I had to convert my Holley electric to manual because my electric would never totally kick off. A carb spacer would only magnify this problem. Do you have an electric or manual? I still think we can lick this problem. By the way...I've never gotten an ebok carb to run right on a hot FE...they are great for the stockers though.

 

OK Pro.
yr on! you think that you can solve this LOL, well, ill tell ya once again what I have:

F250 4x4 ('75) with a 390
headers
duals into dynomax bullets --2.5'' system
ignition--stock duraspark except crane dist curve kit--->I forget which springs i have it it--might be a yellow and a standard or blue and standard?? its been a while but i think i have it where the mech advance kicks in sooner--I THINK i did it right!
carb: holley 1850--600 cfm 4 barrel with vac secondaries
mods to carb:
1)secondary metering block conversion
2)50 cc accelerator pump cam in #1 position
3)BLACK spring in vac secondary housing--no need to kick the secondaries open bec i do a LOT of low speed rpm driving
4)1'' OPEN carb spacer (no heated spacer)
5) main jets on primary side could be 2-3 sizes fatter--not sure
6)idle mix--2 turns out per side
7)current shooter=31 **on acceration it now backfires out the exhaust--but 3/4 to full throttle, it doesnt backfire! just at transition throttle!!! *GRRR* lol
*a 35-37 shooter eliminates the backfire but if the throttle is opened at shut rapidly several times, it loads up then clears out
forget anything under a 31 shooter-too lean
8)never checked the powervalve
i think that is basically it.
plugs are a dark brownish--some are a real dark but not black while others show greyish ash deposits
the weather currently is between 15-25 degrees at night and peaks at about 45 during the day.
Sorry about the long post but if i dont get this thing straightened out, this 1850 is a likely candidate for a paperweight! LOL
regards
Ben

 

Almost forgot

all my chokes are manual--I hate electric chokes! with a manual, less to go wrong!!

regards
Ben

 

Darn, your manual choke rules out my easy answer. It really strikes me as odd though that you'd need that #37 center squirter...the 600cfms come with a #25 and they are usually really needed in something as heavy as a truck. The more you describe your problem the less I think its the powervalve though...it COULD be but I think your symptoms would be worse if it was. You never mentioned your intake, but I'll assume you have one with a heat riser and its not blocked...right? Your plugs sound okay to me, I like to run a little rich and its tough to read plugs now a days with our crappy gas. Did it have this problem before you put in the mechanical advance kit in the dizzy? What is your initial timing set at and have you tried retarding/advancing it and what effect if any has it had on the carb symptoms? Let us know regarding the above...I'm sure its one of those simple little that drives you nuts to figure out.

 

I would put the white spring in the secondaries and let them help with acceleration. With a vac secondary carb like the 1850, your secondaries only open with load - if they are locked out somehow you are running a really little 2BBL with a great big pump shot from that 50cc kit.

I run an 1850 on my 390, only performance mod is an Edel performer cam. Set the timing to about 12 deg initial, used a white spring, a # 21 squirter, stock cam (red?) in #1 position, #68 jets. Runs like champ once it's up to temp, a little cold blooded but that's the elec. choke.

 

boy am i forgetful!
i have an edelbrock performer intake NOT the performer RPM. believe it or not, the truck used to run better with the stock manifold and stock motorcraft 2BBL. As for that curve kit, I dont know what the advance is set to honestly. I put the lighter springs in and then timed by ear. I dont like the lights because they dont take into acct. dizzy bushing wear/slop/play!
On a lighter note, going into school this morning, i had the opportunity to really floor it and hold it there. Guess what? now it breaks up like its starting to starve for gas. I never noticed this before. Im starting to wonder if its bec I have the black spring in the vac secondary? OR is it bec of the open plenum spacer? Should I ditch the spacer and go for a 1 inch 4 hole spacer? I am really getting tired of this! Heck, Ill just spend the $$ and get a 4 into 2 adapter and put a holley 500 cfm 3 barrel on it!
ANy more ideas? suggestions?
thanks for yr insight guys
regards
Ben

 

If you have to have a spacer, try a half inch four hole aluminum. This will conduct heat better which I suspect is a small part of your problem. Frankly, the way you have your carb set up is just darn curious. It should run great on your engine with the stock settings, and yes, yank that black spring out of there. Did you modify everything then have these problems? How did the carb run in stock form...or did it run poorly which is why you modified? I ask because I've known folks to get a new carb out of the box and then tweak it seven ways from sunday before they plop it on there block....and you've tweaked yours allot. Important to know the sequence of things. You also really need to check your timing, both initial and full in, sinch you have a mechanical advance. This can magnify or mimic carb problems. You've gotta get a timing light and check it out...a vacuum gauge is also a big help. Yes, I trust my ear first and foremost too, but to nail these things town you've got to use the right tools. This is a pain in the neck, I know, but its a great way to learn

 

Maybe that 600 cfm is just too small. I run a 1in. 4 hole spacer under a 750 vac. Holley and about the only problem I have is snapping off dana 60 axle shafts. I have to agree about the edelrocks .I ran a carter afb for a while and it just didn't have the power for the kind of hauling and towing I do with it. Got a little better mileage tho.

 

Guys
I think I am going to procure a 4-hole 1-inch spacer this week some time and I am going to install that instead of the 1 inch open spacer. Hopefully, this will help. I am contemplating going back to the stock metering plate setup and taking out the block conversion. I'll decide what to do when I pull the assemby. However, I do know that I will keep the 50 cc pump installed
As for the edelbrocks not having power? on the top end. that is curious. I wonder if it is a tuning problem? Interesting to say the least!
regards
Ben

 

Guys
I finally got around to pulling the carb again ans swapping the 1'' open spacer for a 1'' 4-hole spacer. I also went back to the 31 shooter. Turns out the 28 is too small (lean backfire) and teh 35 is too rich. So, I know I have the right shooter. I kept the black spring in the vac secondary bec I really dont need them opening that much since I do most of my driving below 4000 RPM. I understand that the 600 will in essence be a 600cfm 2BBL but that is OK.
I reset the float level. The mix is set 1.5 turns out per bank. I kept the metering block conversion. However, I also backed the fuel level down on the sec side bec with the black spring in the vac housing, those secs will most likely stay CLOSED below ~~2800 RPM. SOO, with all this said, guess what? I STILL have that nagging transition throttle hesitation. I am just going to resign myself to the fact that this carb will always be like this. Never in my life have I had soo much trouble tuning a Holley. I can set up a 2300 2 BBL with my eyes shut, so I dont know what is wrong here!
I kept that 50cc pump too. I read somewhere that I should use the BLACK cam to get max pump action with the 50cc pump? I have the 2 cams that came with the kit. I installed the one that said #1 What is the difference between the cams that come in the 50cc kit vs the Black cam in the accel. pump cam tuning kit?? I wonder if this is the problem? One final thing, can I swap a 2300 series center hung float bowl assembly for the side hung float bowl on the 4160 series?? I apologize for the long post
regards
Ben

 

Have you tried advancing the timing? No matter how well you tune the carb, if you don't have enough advance you will hesitate when you hit the gas. I didn't read this post all the way through so I'm sorry if this has already been mentioned.

 

With the black spring you have something like a 250CFM 2BBL, I suggest you go to a white spring. Until you let the carb work as designed it will probably always have some weird problem.