Thinking about....

[MAINEVENT]

going from a dual carb high rise set-up to a single carb set-up for gas economy reasons....I think i am way over carbed for a stock bbc i am running a high rise weidland (sp?) and 2 demon 750's and i only have 2 small tanks maybe 24gals total and it does not last that long My question is will i lose alot of horsepower if any??? and will it make a noticible difference and how much running around i can do IF I WENT DOWN TO A SINGLE CARB???
TIA
MAINEVENT

[Aluminum Squirt]

Hey Mainevent, way off topic, but when you say Oak Park, CA, do you mean in the 95817 or is there another Oak Park....?-Aluminum Squirt

[djunkie]

I used to have a tunnel ram setup on my old jet boat with an olds in it. It used gas like it was going out of style. I changed it over to smaller intake (single plane) and it not only got better mileage but it had more power. Tunnel Rams are good for higher RPM's and mine never turned past 5000. With the smaller intake it gave me more torque and I even gained a couple mile an hour. Also it seemed to idle a lot better. The tunnel ram sure looks a lot cooler though but the single carb intake may run a little better with your stock motor. Hope this helps.

[Mr.&Mrs.Budlight]

I second that opinion Budlight

[Jake W2]

You guys that put stock carbs on you motor combos should really think about sending to a carb shop to be set up it will make a huge diffrence in idel and responce.
I had a single Offey TR and I ran a Biggs set up(stage 3) 750 DP mecanical secondaries carb it ideled great and had a hell of a responce and this was on a singel TR not the best preforming manifold .And for you guys that think these are not responsive manifolds I could hop my heavy 77 Bubble deck Tahiti out of the water to the nozzel in two pumps of the gas.You can not set up a jetboat with a stock vac carb it will never preform as good as it could.
Mainevent I could see where you would like the single carb for gas reasons.

[kojac]

Join Date: Jun 2004
Location: Oak Park CA
Posts: 808 Thinking about....
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going from a dual carb high rise set-up to a single carb set-up for gas economy reasons....I think i am way over carbed for a stock bbc i am running a high rise weidland (sp?) and 2 demon 750's and i only have 2 small tanks maybe 24gals total and it does not last that long My question is will i lose alot of horsepower if any??? and will it make a noticible difference and how much running around i can do IF I WENT DOWN TO A SINGLE CARB???
TIA
When I got my first jetboat I put a 468 chevy in it with a healthy roller cam and 12 &1/2 to 1 compresssion . It had Hi performance chevy closed chambered heads and I ran aviation gas for eight years. It had two 750 double pumpers with a wiend tunnell ram on the top.
It pulled a B stainless impellar reworked by Don's pump service to 5700 rpms and the boat ran 95mph at that time.
I experimented with a single 850 cfrm, double pumper, a single dominator, and two dominators.
of course in all of these experiments I had to use different manifolds.
I never got any more than 5700 rpms just changing the carb configurations or went any faster.
One of the dominators that I tried was a Barry Grant 1050 that I borrowed from My machinist friend and it gave me the best response time. It was on a edlebrock dual plane manifold with the dominator flange. But no more rpms at the top end.
It was not until I put the engine on a dyno and experimented with a lot of different combinations that I saw any difference.
One of the conclusions I found was that I could only make 25 more horsepower maximum on a 468 cubic inch with the additional carb and other modifications.
Your basic stock 454 will not make enough horsepower difference with two carbs to notice the difference. The pump absorbs so much horsepower at the upper end of the rpm range that all you will see is more gas usage and less response from your motor at lower rpms.
In order to see a big difference in top rpm's you have to do more than change carbs. You have to change the whole combination.
I still have that boat and it runs 117 mph without the juice at 6800 rpms.
I have found that edelbrock RPM dual manifold with a healthy reworked fine tuned 850 double pumper is the best combo for your present application.
At least that was my experience.
Hope this helps.
kojac

[MAINEVENT]

Thanx everyone but i tink i need to explain myself alittle bit i am not trying to get more rpms i am just wondering if i will LOOSE HP by going down on my carbs i am not gonna build this motor to run alot quicker its just a cruiser for the fam (plus its paid for :D ) but my main questions are probably Am i over carbed for a stock 454????and Will i loose any ponies by going to a single carb setup????

[OMEGA_BUBBLE_JET]

you will use MUCH less fuel and loose no measurable hp. you may even gain some torque/hp in the range you operate in. you will be pleased with the results. I recomend a good dual plane manifold as well with a mechanical secondary carb. I personally run an edelbrock performer RPM with a holley 750dp. I am very pleased with it and I can run all day and only use half of the 22 gallons I hold. I spin my BBF 5400rpm on the big end.
tunnel rams seem to be very popular on the west coast and you should have no problem selling your current setup. I say do it and don't look back.
Omega

[MAINEVENT]

you will use MUCH less fuel and loose no measurable hp. you may even gain some torque/hp in the range you operate in. you will be pleased with the results. I recomend a good dual plane manifold as well with a mechanical secondary carb. I personally run an edelbrock performer RPM with a holley 750dp. I am very pleased with it and I can run all day and only use half of the 22 gallons I hold. I spin my BBF 5400rpm on the big end.
tunnel rams seem to be very popular on the west coast and you should have no problem selling your current setup. I say do it and don't look back.
Omega
Thanx for the info i will look into how a set up will run me and how much i can get for my set-up now
1 high rise
2 demon carbs 750's might keep one though and just use it on the new manifold