Carbs for 468

[DEL51]

Hi folks, I bought a different boat and I am getting my freshened 468 ready.I have 2 1150 doms but feel they are too much for what I intend to do. I purchased a tunnel hull,19ft centurion, with an ab cut impeller.I was told this pump turned 6500 rpm with a tunnel rammed 477 chev.My 468 turned an aluminum A @ 6300-6400 rpm,Max tune,in my old sanger. I want to underdrive the blower and make around 600-650 horse and keep the rpm under 6400. I want to get experience in the "new" boat before adding more power.I hope to run 7-8 lbs of boost, littlefield 871, nice heads, headers,etc.I am considering 2 edelbrock 800 carbs or holley 750's.I don't want to mess arund with boost referencing power valves.All suggestions welcome.
Thanks,DEL51

[Fiat48]

I have had friends that have tried to use the big dominators for mild blown lake use and have been unhappy. I sure wouldn't want to get smaller than 750's though. I beleive Holley made a #6109 750 cfm that could be mounted end to end, saving linkage problems and were quite adequate with mild lake blowers. Don't know if they still make them or not. Hope this helps.

[Heatseeker]

I heard the 6109's are discontinued. There was an ad on dragboats.com for a set of new in the box 6109's. You might check there. I'm running 4223 850 center squirts. I squared the jets and blocked the power valves. Seems to be just right for now. I am making some larger squirters to try and get rid of a small cough on hard acceleration.

[sgdiv7]

Hey HEATSEEKER, how far is the butterflys open, is there more then .010 showing of the idle feed slots? if there is drill the butterflys .090 to start and increase as nessary so you can close the butterflys more so they don't dry up. a blower motor will suck those slots dry if the butterflys are open to far which will give you that cough. If that doesn't totaly cure it increase the idle feed restrictors .003 at a time until it goes away. I perfer the the boost ref. power valves my self because you can tune the motor to be more efficient crusing when not under boost. Some people have deep pockets and don't stray far from the gas docks. What size are your squirters now?
Bill

[blowncarrera777]

Del, I'm also running a 468, mega blower with 750 double pumpers, 5lbs boost with 4.5 p.v.. makes about 625/650 hp and runs and idles great all the time. them 1150's sound awful big for what yu want. My 02 worth. I'm running an arneson sur. drive at about 5600 w/ 26" prop. goes to 6000 w/ the smaller 23 on it

[DEL51]

Carrera,Did you have to boost reference the power valves?Do you have the part number? SGDIV7, could I use one 1150 dom ,model 9377,?

[Infomaniac]

DEL51: Hope you like the new boat. It will turn more RPM's just because of the impeller difference. If you are not having problems with your old carbs. I would keep them on and just underdrive the blower until you get the power you are looking for. Pulleys are much less expensive than carbs.
Any size carb. is never too much for a blower. An 8-71 will draw more air than any 2 carbs will flow. The only thing with doms is they are not cruise effecient unless they have intermediate circuits.
I would be willing to bet it will not be long before you will want to haul some serious ass. If you detune and buy smaller carbs. you will not be happy when that time comes.
If for some reason you buy smaller carbs. I would fork out for 1,000 CFM holley HP double pumpers. They are more cruise effecient and will flow plenty if (when) you decide to step it back up. You can tune them down easily for underdriven conditions. We can fix you up with carb. jetting etc. if you buy Holleys. No need to boost ref on your type of boat. I cannot provide any help with Edelbrocks.

[sgdiv7]

I don't think one 1150 would work on a blower not enough cfm. I bought my carbs new and they came boost ref. they were not cheep carbs, hp 950's for blower motors & 8-71 superchargers. When you get them you still have to do some mods (like power valve restrictors holes) because they are mad for drag racing. I have them dialed in now and I have the best of the power and economy world now. Its easy to do if you understand how carbs work.
Bill

[DEL51]

Thanks for the advice,I am going to put both 1150 carbs back on and run the jets a little big,(98), squared and see where I am at.Stock was a (94) I now realize that I should start somewhere familiar and make changes if needed.I can alter jet size if needed. I will try to get some pictures when I finish.I do think these carbs have an intermediate circuit.I looked at the holley website and they said it has 3 circuits. Take care.Thanks!
[This message has been edited by DEL51 (edited June 16, 2002).]

[Heatseeker]

Originally posted by sgdiv7:
Hey HEATSEEKER, how far is the butterflys open, is there more then .010 showing of the idle feed slots? if there is drill the butterflys .090 to start and increase as nessary so you can close the butterflys more so they don't dry up. a blower motor will suck those slots dry if the butterflys are open to far which will give you that cough. If that doesn't totaly cure it increase the idle feed restrictors .003 at a time until it goes away. I perfer the the boost ref. power valves my self because you can tune the motor to be more efficient crusing when not under boost. Some people have deep pockets and don't stray far from the gas docks. What size are your squirters now?
Bill
Bill,
I haven't ever really paid that close of attention to the transfer slots. I will definitly look next time I have the scoop off. I just got done installing some squirters I made up. They are 35's. It had 25's with the nozzles before.
I'll eventually go the boost ref. route, when my next blower motor is done. Then I'll try drilling the butterflies and if neccesary. the idle restrictors.
Suprisingly, the old Heatseeker doesn't do too bad on a tank of gas.
Thanks for the tips.
John
[This message has been edited by Heatseeker (edited June 16, 2002).]