Hi Guys,
anybody got any experience/advice whether or not an 800 cfm spreadbore holley 9023 double pumper/ mech secondaries,has any redeeming qualities for a 9.2:1 454 BBC/268H comp xe? I picked one up at a local swap meet for $100. appears to be in great shape. Threw a kit in it, although I kinda had to piece it together as they are kinda an obscure carb. Could possibly be a marine carb. Got it running reasonably well, playing with the jets. started with a 61 that was stock in the primaries. has 86 stock in the secondaries. bumped it up to 72's on the primary side, but I think I might back it off to 65's tomorrow. has a power valve front and back. the kit came with 6.5's, but it was originally 8.5 front and 6.5 rear. What I am thinking is with those tiny primaries it may be fairly economical on the street until you open it up to those great big secondaries? think this will work, or should I just scrap it and get a sqaure bore carb of some kind? please let me know what you think!

I haven't messed with an 800 speadbore but I have a 650 speadbore that I had good luck with for street strip use. If I were you I would not richen the jets until you run it with the stock jets. Often they are a little too rich to begin with. Holley doesn't want to have someone burn up a motor because they took one of their carbs out of the box, bolted it on and went racing. It's been so long since I had run that carb that I can't remember what jets I ended up with but I do know that the primary jets ended up being around a 57 when I hit the best mix of power and gas milage.

454s come from the factory with a 750 spreadbore. The 800 may be a little large but can be jetted down. Still may not idle great.

yeah,
it did take a little coaxing for the idle, but I think I got it now. I had to balance the secondaries to the primaries very cautiously.It's pulling 15" vac at idle, so it seems happy. I had a bit of a stumble at first, so I had the jets kicking around for testing. The 72's definitley got rid of that. I advanced the primary pump cam from position 2 to 1. It has a white cam right now.It has 30cc front pump and 50 cc back pump. I am wondering if the small diameter bores up front might have some negative characteristics. I am thinking jetting it down to 65, and getting a 10.5 power valve instead of the 6.5 currently in there. whaddaya think, compromise with an 8.5 and go back to the stock 61 jets?

I run an 800 spread bore on my 350 small block and it is the best carb I've used and I have tried many different carbs over the years. The second best carb I've used is a model number 4010 list number 84013 which is a 750 double pumper. The spread bore is great for street/strip because the small primaries will give you great throttle responce and when you mash the gas those huge secondaries kick butt. You will be happy with your purchase.

Get th 4011. It is the new version of the 800 CFM spreadbore. It is far superior to the old style.

well, I just got back from a cruise thru the beach strip and it behaved really well. even in stop and go. It did have a slight surge at very light throttle holding 2nd or 3rd at a very slow 10-15 mph. More of an occasional hiccup. It is cruising at about 16-18" vacuum at 40-50 mph (cruise not mashed of course). stuck a vac gauge on it driving and it drops down to about 5" at a full primary 1/2 mash on the throttle. seems very crisp and a little lighter on torque, which right now is not a bad thing as I have problems connecting on the launch. The top end compared to the 650 dbl pmp I had on there is night and day! wow! now I just need the suspension to handle it all. maybe just a skid pan for those country bumps! welcome any more input for the jetting and power valve selection given these variables. seems to have a spot in the transition from idle to main circuit with the 72 jets up front and 6.5 " power valve (not real big but subtle stumble-momentary).. could be indicating over rich? I have not seen the plugs yet. a little early to tell, and I feel like drinking!(not wrenching) Thanks.

for those who care,
to follow up I went with 65 jets and a 10.5 power valve in the primaries.set initial timing to 12 degrees, running 20 degrees mechanical and 20 degrees of vacuum,fulltime manifold. recurved the distributer with silver/blue spring combo and installed an adjustable vacuum advance, which I am still dialing in. I still have a little detonation when I mash on the throttle at 10 mph, but it's getting better. So far, I like it, but it's still too early to tell. anybody got any tips for adjusting the vacuum can for a BBC? how many turns do you figure?

i looked it up and came up with 64/90 for stock jet sizes.i have always liked the quadrajet and have always wanted an 800 spread bore but haven't come across a deal on one yet you lucky dog you.