Carb question

[396_WAYS_TO_SPIT]

I am putting on a new tunnel ram on my 455 olds along with the new rebuild. The motor will be a mild 455. I think the new cam will be around 230@ .50 duration with a 110-112 lobe sep and .510 valve lift. The comp should be around 9 to 1. What carb should I run? I have 3 carbs laying around. They are 2 750 cfm holley vac sec, 1 750 doulbe pumper(needing rebuild). I have a 750 vac sec on it now and it ran good. The tunnel ram is set up for single carb. I dont want a dragster. This boat will be my little cruiser with a large rooster. What do you guys think. Some people out here at a local shop told me that the 750 vac would be fine. Another guy told me I would need a very large carb (No matter what kind of intake) because 455's love huge cfm and they will run alot faster with more cfm. I dont want to spend $500 on a carb for my little cruiser.
Any info woul help, thanks guys
396

[BigGmarine]

The guy I bought my boat from said that he tried
a tunnel ram on it and it performend like DOG $hit.
It is a built 455 motor with an old stealth intake on it now with a 850cfm double pumper . It runs great and I can run away from those dudes with chevys :D :D :D :D

[Dennis Moore]

You can't use a single four barrel on top of a tunnel ram base (I know they make em but it doesn't work, bad fuel distribution). I think it is really cool for an Oldsmobile to run two fours on a tunnel ram because of the intake port layout, in fact I was going to suggest you run the Offy tunnel ram.
BUT
You GOTTA have two four barrels. The plenum is divided so you have to run two carbs in line. Your going to have to step up and buy a couple of 600 Edelbrock Marine carbs. But it will run good!
Dennis Moore

[396_WAYS_TO_SPIT]

I totally understand where you are comming from Dennis, but I see jordanpaulk's boat at the lake every weekend and he has a tunnel ram and a single carb. His boat runs like a bat out of hell.I dont know his set up but his boat really runs well. I dont second guess your input dennis but I really dont want to put too much $$$ into this boat untill my other boat(454) is finished. So my question is why does jordanpaulk's boat run so well with one carb on a tunnel ram?
396

[rktpwrd]

What kind of head work is done and what kind of exhaust are you running? Huge carbs don't necessarily = more hp. Too big of a carb for a given engine gives lazy velocity in the venturis. Less velocity has less signal to the boosters which gives you less throttle response. Been there lol.
The big block olds was designed for low/mid range torque hauling around large heavy vehicles. I would not use a tunnel ram, it's more for the show factor and that's about it. If your turning 6000+ with ported heads alot of guys prefer the single plane; Edl torker, Holley street dominator, Offy port o sonic and with a dominator carb a Offy super sonic. Either way all of the intakes are outdated designs.
With stock heads or even mildy ported heads and a max 5500 rpms. I'd go with a Performer intake manifold, 3310 carb or 750 dp, and maybe try a 1 or a 2 inch carb spacer. Less hassle tuneup wise and alot of torque probably could get close to 600ft lbs with that cam, headers and some head work. I'd go with the 110 LDA or even a 108 LDA.

[396_WAYS_TO_SPIT]

Head work will be a standard 3 angle valve cut and my exhaust is basset open headers.

[Hotcrusader76]

396_WAYS_TO_SPIT:
Another guy told me I would need a very large carb (No matter what kind of intake) because 455's love huge cfm and they will run alot faster with more cfm. I dont want to spend $500 on a carb for my little cruiser.
Any info woul help, thanks guys
396If you are after a cruiser type of boat, stick with that vacuum secondary carburetor. When properly tuned it will serve you well. Do a 4150 conversion on it so that you can have adjustable secondary jets, mill off the choke horn if you do not plan on having a choke, do a nice overhaul on it and you can have a perfectly rebuilt carb under $75 or so. Otherwise your looking closer to $200-250 for a specialist to perform the same, but without the hassle of doing it yourself.
Good luck on your set-up!
-Ty
[ September 26, 2002, 10:42 AM: Message edited by: Hotcrusader76 ]