Reply With QuoteMy dad has duals on his 460, I forget the exact size, and he is also running a fairly aggressive cam. The boat runs great
http://www.supermotors.net/getfile/1...g-029small.jpg
Should I Dual Qaud a 460?
Quastion:
I have a 1968 460 in a Belmont 18, mild v. stock but strong lower end and heads. 68 was a higher compression year. Currently running an aggressive cam (#Â’s not handy)/springs with edelbrock performer RPM manifold and edlebrock 750 carb. Headers. JG pump with A2. Runs good, no idea of top speed yet, peeks RPM of about 4800/5000
I keep getting drawn into SummitÂ’s Dual quad setup for the 460. Weiand Manifold and either 450 cfm or 600 cfm carbs. I know the power band shifts to over 2500 but I seem to be at or above 2500 constantly.
Any thoughts on dual quad setups? Pro's/Con's? Thanks and respect. Frank
My dad has duals on his 460, I forget the exact size, and he is also running a fairly aggressive cam. The boat runs great
http://www.supermotors.net/getfile/1...g-029small.jpg
Honestly, my vote would be no. I switched from a Weiand Stealth and single 850 dp carb to a tunnelram with two 660 center squirters and gained nothing. Obviously my 500 hp mill didn't require any more air/fuel than it was getting with the single 850. If I were to run a different cam, things might have been different performance-wise, but my fuel economy would still suck. Granted the 660s aren't known to be an economical carb, but my gas mileage/hourage went way down. The way the linkage sets up on the 660s, anything over 3000 rpm and the secondaries are opening already.
The 600 cfm vacuum secondary carbs that a couple of my buddies run work well and didn't hurt their fuel economy too badly. However, it didn't help their performance any either. Apparently they had enough air/fuel with their old setups as well. One of them purchased the same setup from Summit that you're looking at.
That's three boats that made the switch and nobody gained anything. All three boats start right up and run great every time out. They just don't go any faster.
From what I've seen, it's purely a bling thing. There are some nice sheet metal tunnelrams, and possibly some other mass produced TRs out there for the BBFs, but the Weiand isn't that great.
If I had it to do all over again, I'd run the Victor single plane and a 950 or 1050 dominator.
http://www.homestead.com/jetboat/motor_shot.jpg
Just my personal opinion from my own experience and that of others I boat with frequently.
P.S. since I sold all my old stuff I'm seriously considering selling the 660's and buying some 600cfm (or maybe even smaller) vacuum sec carbs just to get some of my economy back. Obviously it's not going to hurt my performance much since it's still 1200 cfm if everything opens.
Or possibly some smaller mechanical secondary carbs with a more progressive linkage.
Should I Dual Qaud a 460?
I have a 1968 460 in a Belmont 18, mild v. stock but strong lower end and heads. 68 was a higher compression year. Currently running an aggressive cam (#Â’s not handy)/springs with edelbrock performer RPM manifold and edlebrock 750 carb. Headers. JG pump with A2. Runs good, no idea of top speed yet, peeks RPM of about 4800/5000
I keep getting drawn into SummitÂ’s Dual quad setup for the 460. Weiand Manifold and either 450 cfm or 600 cfm carbs. I know the power band shifts to over 2500 but I seem to be at or above 2500 constantly.
Any thoughts on dual quad setups? Pro's/Con's?Generally speaking, a tunnel ram setup can offer more mid-range and top end power than your current carb and intake for sure; whether or not your particular engine will benefit from the swap is questionable.
Based on the description of your engine, I assume your C8VE-E cylinder heads are unmodified. If this is the case, then yor engine would benefit much more by porting them. With the increased breathability of your top end would come the benefit of the proposed tunnel ram. That being said, tunnel rams on typical (lake boat) jet boats like yours offer about 40-50HP gains, and this is negligible--if even noticable-- at the jet pump (unless you are trying to squeeze every last bit of HP from your engine).
I personally like tunnel rams. I like the idea of having a carb venturi poised over each intake runner, I like the look, I'll even claim the modest performance gain. But, if you swap 2 fours for your Carter gas miser carb, you will downright shit in your pants when you think you just broke down in the middle of the lake...only to find out your fuel tanks are actually bone dry after just twenty five minutes of run time.
Turning 4800-5000 with your current package sounds like a good combo. Not sure how much a T/R will change that. But without knowing your cam grind, I can safely say that you would better benefit from both a cylinder head port job and a tunnel ram with the 2 fours.
http://www.***boat.com/image_center/...r_Overhead.jpg
If you are indeed a naval officer and sitting on a pile of cash from all that military time and now you want a tunnel ram, then plan on using your remaining tens of thousands of dollars on all that fuel for the boat.
LO
From what I've seen, it's purely a bling thing. There are some nice sheet metal tunnelrams, and possibly some other mass produced TRs out there for the BBFs, but the Weiand isn't that great.
.
The Weiand out of the box does not work very well. It needs alot of plenum work as well as a good port match. After several hours with a carbide burr and a rather large pile of aluminum chips on the floor my Weiand tunnel allowed the engine to go from a very lazy 66-6700 rpms to over 7500 effortlessly, no other changes to the engine. [this is in a v-drive with a BBF- 2 850 d/p Holleys]
The Weiand out of the box does not work very well. It needs alot of plenum work as well as a good port match. After several hours with a carbide burr and a rather large pile of aluminum chips on the floor my Weiand tunnel allowed the engine to go from a very lazy 66-6700 rpms to over 7500 effortlessly, no other changes to the engine. [this is in a v-drive with a BBF- 2 850 d/p Holleys]
I should've quantified my response. I haven't even so much as gasket matched my TR. Nor have the other two guys that I boat with. No doubt performance could be improved over the stock piece if somebody knew what they were doing and worked it accordingly.
However, even taking this into consideration, part or our problem (being jetters) is that we're somewhat limited by impeller/pump. I don't think my motor could ever pull that kind of rpm without running a C or D cut Berkeley or equivalent. That being said..........I'd more than likely not be able to hit the rpm range where the setup could really benefit from the TR.
With an AB Aggressor impeller I'm only turning 5300 rpm on the motor, and 5600 with a 150 shot. I've already sacrificed some holeshot due to the smaller impeller cut (in the form of slippage) and wouldn't want to go much smaller.
Thanks for the input 058. I don't suppose you have any pictures of the before and after?
P.S. not to be glib, but how's your fuel economy? I realize that it's not exactly a primary concern and I know you're probably doing better than us jetters, but I'm curious as to how much difference a prop would make over a jet pump.
Bootom line is that duals are very high on the bling factor but the need for them at modest RPM/HP levels is questionable. It takes a pretty stout motor to need more than a Victor with a 1050 on it. No doubt there are plenty on here who have an excellent running TR set up that is pretty worry free but it has to be more difficult to set up duals than a single, from tuning and cleaning to float adjusting, jet changes and parts replacement. I vote for a good single intake that is port matched, put a spacer in there and get some dyno time to make sure it is jetted spot on, I think that will be money better spent than going to a TR. If you can't resist the bling factor, have it polished and put a scoop on it. Just my $.02-Aluminum Squirt
PS-(if you're a fly boy) thanx for dropping those 2000 lb'ers where we need 'em, the boys on the ground appreciate it
Should I Dual Qaud a 460?
Quastion:
I have a 1968 460 in a Belmont 18, mild v. stock but strong lower end and heads. 68 was a higher compression year. Currently running an aggressive cam (#Â’s not handy)/springs with edelbrock performer RPM manifold and edlebrock 750 carb. Headers. JG pump with A2. Runs good, no idea of top speed yet, peeks RPM of about 4800/5000
I keep getting drawn into SummitÂ’s Dual quad setup for the 460. Weiand Manifold and either 450 cfm or 600 cfm carbs. I know the power band shifts to over 2500 but I seem to be at or above 2500 constantly.
Any thoughts on dual quad setups? Pro's/Con's? Thanks and respect. Frank
it's not worth it as stated in the aboveformentioned.
Thank you all, learned much. Guess I'll stick with what I have. Runs good, economy is excellent and still has enough to scare the friends not used to these types of boats. Have to GPS and see what I'm getting - just now finishing test runs. Bling is cool, right combo is better. Damn Summit with that picture every magazine!
Guess I'll search ebay for a fixer-upper flat bottom v-drive for top end speed. But this jet with a mild v-hull (and reverse!) is an awesome thing when you see an ocean liner making sSSSwelllllllSSSSsss on the lake.
Thanks and respect.
Frank
Thanks for the input 058. I don't suppose you have any pictures of the before and after?
P.S. not to be glib, but how's your fuel economy? I realize that it's not exactly a primary concern and I know you're probably doing better than us jetters, but I'm curious as to how much difference a prop would make over a jet pump.
Sorry, No pics of the before and after, never been big on photo documenting stuff....dunno, I guess I never think about it, I just kinda jump in, do it and WA-LAAA....its done. Fuel economy is not a big consideration esp. when its 110 ERC race fuel. I will say I can make several good passes and still cruise around and I've never ran my 1- 10 gal. tank dry.I will suggest the next time you have the manifold off the engine you might want to get into it as it may yield some good gains. Might save ya some $$$ on N2O.
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