tunnel ram or single carb edelbrock 850

[YeLLowBoaT]

My experiance with off road says they don't like to bounce, and spill fuel easily. Just my observations, wouldn't want that prob with my boat.
that would be a very good reason. never had one in a boat, put one on my mustang and never had a prob with it.

[LakesOnly]

Why don't you care for the edelbrock carbs? more just wondering then anything else.The Holley 850 will almost invariably make more power and can be more precisely tuned for upper rpm fuel delivery.
I like Carter (Edlebrock) carbs and have run them on other vehicles...in this particular case (jet boat) it's more a matter of the most appropriate carbuetor for the application. Best analogy right now would be the point of running the (upper rpm applicable) Victor 460 over the (low rpm applicable) Torker, which is just not right for the jet boat.
LO

[speedymopars]

that would be a very good reason. never had one in a boat, put one on my mustang and never had a prob with it.
I've run them in plenty of street cars (and they worked well), but always had a problem with them in off road situations.

[gas Hogg]

okay so it looks like I want to go the tunnel ram as long as I want to fill the two tanks up ALOT. Being that I take my boat out of the water every time that will not bother me that much. As far as the other set up it's a 850 marine edelbrock. I thought I would be safer with the marine model. The two holley 600's where just rebuilt and should be ready to go. I was just worried about breaking in the engine with trying to tune in two carburetors. Chris Zootis in Healdsburg built the motor for me and he said he would set up the carbs but it will take awhile before he can fit me in.
I had built this engine wanting to go with the tunnel ram. I realized the gas problem but my company can pay for most of it. So with what you are saying I'm thinking of going that way.
But would it be better for the engine to break it in with the single carb?
Thanks again your web site looks great and you will hear from me soon. There's a few more parts I could use.

[thatguy]

Are you a racer? Do you get time slips?
If not, who cares if you give up a little dyno power. (I don't think you will)
Run The TR! Every time you launch with the 4 bbl and some guy slips his boat in with all the goodies and a tunnel ram, well, you may wish you had it on.
Face it, we LOVE to show off our boats, AND go fast!
I did the same thing. Agonized over which to put on. I went with my polished TR and the 2 660's that came on it. Best move I ever made. (454 w/Brodix Al. Heads)
Boat hauls arse! AND looks killer. Now it may or may not go faster without it, but it starts and idles perfect, (1000 RPM), goes 86 GPS'd, and the girls love it and their boyfriends are jealous!
Yeah, I know the gas pump guy by his first name, but so what?
Do the right thing. TR.
Tommy

[Squirtcha?]

Here are links to some threads (archived) where this subject has been covered before. I just didn't want to type all that stuff again.
To summarize................Been there done that. Switched from a Holley 850 dp and dual plane manifold to a tunnelram and two 660s. Gained nothing and was further awarded with some really piss poor mileage.
http://www.***boat.com/forums/showth...ight=tunnelram
http://www.***boat.com/forums/showth...ight=tunnelram
There are some more under the search header, but much of it is repeated.
http://www.***boat.com/forums/search...archid=2023320
Good luck with whatever you decide.

[LuckyDaze]

I have heard people complain about fuel economy with their Tunnel Ram and that tells me that their engine is over carbed. I have TR and I get GREAT economy. However people tell me that I am under carbed. I launched from Topac, ran my boat down to the sand bar, then down the the Havasu channel, screwed around and did a couple of high speed full throttle fun times on my way to copper canyon, then back up to the channel, then back to the sand bar, and play'd around some more and then back to Topac. Total usage for the day was 11 gallons. I have two 11 gallon tanks in my boat and I had a smidge under 1/2 when I pulled her back on the trailer. That was with my tunnel ram and lots of fun for the day.
I am running an old school Offy with dual 450's on my 454. Im running about 10 to 1 with a fairly lumpy cam and she pulls 5200 RPM with an A impeller. I couldn't ask for more. I love the setup. So, Go with the tunnel ram and carb according to your needs, too much and you'll be wasting fuel. They look great and my boat is like driving with fuel injection. My engine pulls so hard on those little 450's that it is responsive as all hell.
~Brian

[speedymopars]

I can only relate to street cars but - An engine takes a specific amount of fuel to make a specific horsepower. A jet takes a specific hp to drive a specific RPM. If you have too much fuel, then you get poor mileage. If you don't have enough, you don't make enough power.
A tunnelram itself will not make your mileage go down, but if you throw too big of carbs on there, then you will make the carbs rich (change in metering signal), and you will have poor milage. Performance, mileage and response can be gained back by changing the jet size to a smaller set on the carbs.
On my duster, when it had the smaller engine in it, I saw a 1 mpg increase in highway fuel mileage with the tunnel ram once everything was tuned.
Now, this is assuming you keep everything the same.
If you bump the carbs up in size (total CFM), you can flow more air, hence more fuel at WOT, and there your mileage may go "down" but it's the same if you went from a 600 cfm 4 bbl to an 850 DP. It all gets back to brake specific fuel consumption. You are making more HP, so you need more air, and the additional fuel that goes with it.
If you ran a 900 CFM single 4 bbl on an intake, then converted to 2 450CFM's on a tunnelram, you would make more HP everywhere do to the efficiancy of the intake, but you would see little to no change in mileage. It's all in the carb tuning.

[pw_Tony]

Have had a lot of success with the 450 Holley Double Pumpers

[gas Hogg]

Well it looks like I now have a 850 marine edelbrock carb for sale. New in the box as the saying goes. I'm bolting the TR up tonight, thanks for the input. Sounds like I have a new boat anchor with the manifold. Paid a hundred for it then bead blasted it so no big loss. :idea: