I am helping my father inlaw build a 32' Roadster and I have been swapping around some of my parts with him to get some components for his ride. He traded me a BBC for a SBC that I have, to install in the 32'. He really wanted a multi-carb setup to use with the SB. I have a tunnel ram that I told him he could have but then he decided he wanted a tri-power setup. He just picked up a edelbrock intake and rochester carbs setup complete that he is planning on using. After some looking at my Weiand tunnel ram and a BS session, we were just thinking of modifying the dual four upper plenum into a tri-power. I had a look around on the internet and have found a couple of setups like this. It seems like it would be pretty cool setup and should have potential to run hard. The single centered two barrel carb should be able to work on the street as well. Seeing as the tunnel ram is just a giant paperweight, sitting on my shelf for many years, and I like to fabricate things, I think I might give this project a try. I think I will trim away the big casting lugs for the four barrels then machine the top flat. I will probably make a bolt on top plate with mounts for three carbs spaced about the same as the edelbrock tri-power. I am thinking 1/4" aluminum top with a 1" thick spacer under the carb. What do you guys think? Am I waisting my time. It seems that a Weiand tunnel ram for a SBC is worth piss-all anyways. Why not make something unique. I think it would look pretty cool under the hood of a 32'. I believe we could tune it to work pretty well with my solid cammed 350, 4 speed and somewhat low rear gears. Anybody have experience in something along these lines? Greg
see dashman here on hamb for custom machine work........ don't stop there make it a real tunnel ram .... ben at dashman also made some phelonic spacers......
Now that is really a tunnel ram alright. That is super high. How does it run on the street? I was more thinking of something like this. This one was done with a Edelbrock manifold. I am not crazy about the full polish or the air filters but otherwise it is pretty cool. Greg
Greg I ben thinking about doing the same exact thing. Wasnt sure if Rochesters or Strombergs but cool idea. Heres where I'm at. Scott
That is exactly what I had in mind. It looked like that casting is plenty beefy to machine flat and bolt to. Now that I see your picture I am sure that will work well.(or did you weld a flat piece to the top) Looking at your picture I am quite sure that I could just use a piece of 1/4" or 3/8" plate to bolt across the top of the opening like what you have there. I think I will then just use 1" spacers under the carbs to give clearance for linkage and such. Should work sweet. You could basically make a couple of tops if you want. One for Strombergs and another for Rochesters or even Holleys. I might do this for a winter tinkering project. (like I need another project) Thanks for posting. Greg
When Hot Heads designed his early Hemi tunnel ram, he made the top plate the same mounting pattern as the carb adapters for 6:71 blowers... so any top plate that bolts to a blower would work on his tunnel ram. That's a nice design parameter to keep in mind. Less fabrication, and readily-available parts that are cast and look factory-built. Backing that up, he then designed his own top plate that mounts 3 Holley 2bbl carbs like those found on Mopar 340-6 and 440-6 Pack cars. The carbs and linkage are readily available, and any factory Mopar 6-pack air cleaner assembly will work, including reproductions. You could do the same thing with Ford or Corvette tri-power carbs, though that's probably more expensive. Food for thought. The Holley Mopar 6-pack carbs are rated at 1350cfm: 350cfm for the center "driver" carb, 500 cfm for the two outboard carbs. It should also be noted that the cfm rating of a 2bbl carb is NOT the same as a 4bbl carb. They are measured at a different Hg level... I think the conversion is 1.4:1, so 1350cfm of 2bbls is equal to a 964 cfm 4-barrel. Basically, you're running a Dominator, but driving around on little bitty butterflies until you tip in the big'uns. -Brad
Here is one of the plates that Ben did for me. Also shown ( top and bottom) is the HotHeads 3x2 top plate.
The first top (in red) is almost exactly what I had pictured. I was just going to do the carb spacers separate and bolt them down to a plate. I would also do a four bolt Rochester carb flange. I wish I had access to a milling machine still. I used to use the one I had at my old job plenty. It would be a fun machining project. Greg
I have built two of these. One for a sbc and 1 for a bbc. I used a edelbrock71151 and the holley version of this for a sbc. They both have a large single plenum. For the sbc I set it up with 1 normal and 2 dumpers. It worked great. The bbc 454 I set up with two normal rochesters and 1 dumper in the middle. They both use a single plate which I made of1/4 inch aluminum plate. I used a progressive linkage on both. Very simple. No problems. Good luck.
Have any pictures of your combos. So you ran two normal carbs with idle circuits and all on the big block. That seems like a good idea for feeding a bigger engine. How was it to tune? Thanks for the info. Greg
On a sbc , a single center carb and 2 dumps will run better than the 2 carb with circuits and 1 dump . You really don't need that much carb for a street sbc engine to run good . Just don't over carb your set up or it will be a pain in the ass to to get running right . 3 GM's will be a really nice set up but you will have fun finding 3 side feed carbs at a fair price . Holley 94's will be the cheapest way and 97's will be more costly than 94's . The 94's & 97's will give you that more old skool look . really depends on what look you are going for . Just my opinion . Retro Jim
I totally agree about the sbc and having only one carb with idle circuits. We will likely use three rochesters that my father in law just bought as a complete tri-power setup and then play around with the tunnel ram as well for fun and experimenting. I was just intrigued with the two having idle circuits and one dump for a big block. I also have a big block 496 with undesignated home and have a buddy with a Weiand BB tunnel ram taking up space on his shelf. I was just considering building a combo for the big block as well, if the small block one works well. Thanks again for the info. It really is too bad that the carbs are so pricey. I would kind of like to try 3 holleys from a 440 six pack on a big block tunnel ram. I think that would work well on the street and look cool and probably run well. Lots of projects, so little time and money to play them out. LOL Greg
iwent the otherway. I took a wiend SS manifold for a six pack cuda and made a 2x4 tiop. it worked very very well. That manifold is a crossra m/tunnel ram if you will but the work would be the same. I made it first in 3/4 plywood. Sealed it wth garage floor paint (oil /fuel proof) and ran it on the car. When the ET slip said YES!!!!!! I took the wooden part to the local foundry and had it cast in aluminum. . There was zero difference performance in the two (wood vrs aluminum) which was something I worreid about. Article about it appreared in Chrysler Power mag in the 90s. Don There is a pic of the finished aluminum one on my website under some of the projects pages.
That upper plenum will probably bolt on the Weiand TR for the small block Fords.. I believe they share that same bolt pattern with the chevy virsion
Maybe you can use one of our blower plates for the 6-71 to make something work, we have all different kinds of carb configurations. If you don't see it give us a shout, we can always custom machine one for you. Dashman's Hot Rod & Speed Parts www.dashman.net
That looks almost exactly what I would be looking for. Your Rochester tri-power blower top is basically what I was thinking of making. The only question would be if the lower plate would match the dimensions of the tunnel ram plenum. When I actually get the tunnel ram plenum machined down to a flat surface, like the one in the 4th post by drifters there, I will get the dimensions and maybe give you a call. Might need to make a custom lower plate to match those dimensions then use the same spacers and gaskets as your blower setup. It could be something you could offer in the future. A guy could send you the upper plenum you could machine it flat and install the plate and carb adapters. It would have a pretty cool look to it. Thanks for the post. Greg
Greg, If you can use your imagination on this one it may give you an idea of the size of the tunnel ram top verses the blower top. The other pic is an idea some of my customers have, it's to build another box and put a top similar on the intake. There has been a lot of interest but nobody has committed yet. Still there has been a lot of great ideas on how it should be done. Dashman's Hot Rod & Speed Parts www.dashman.net
Thanks for that info Dashman. It looks like the blower adapter plate is quite close to the right size already. Would it be possible to get your outside dimensions for that plate? It looks to be 5 1/2" wide but I could use the length too. If I have those dimensions I could machine my tunnel ram plenum to suite your piece. I thought about making a complete upper plenum but it looked like quite a bit more work than just modifying the Weiand one. Greg
Tuning was easy. It ran great. I no longer have the car and unfortunately no pics either. I am thinking about doing it again though. I will have pics this time. I BELIEVE THE LARGE PLENUM DEFINATELY HELPED.
Greg, It is 5 3/8" x 14 1/4" on the plate, it looks like there is plenty of room on your tunnel ram top to accomplish what you're up to. As you can see it fits pretty snug on the supercharger picture. Dashman's Hot Rod & Speed Parts www.dashman.net
A friend of mine did this on a 533 bbf. He used holleys and I believe it was setup straight linkage. It looked different and worked great. Another carb you may consider is the large base 2g. You can buy these rebuilt from jet for just over $200.00 a piece. They're rated at 500 cfm, might be a better choice for your BBC. I built a 6x2 setup for my 582 chevy with these. You have to be a little more creative with the fuel lines since they're front feed.
I know this is a kinda old thread but ive been thinking of doing something similiar to this. What if you ran a weiand single four barrel TR intake with a three 2-bbl adapter plate finished off with scoops. Would there be any problems with this type of setup?? Thanks for the info... Justin
I know it has been a long time but I finally got some time to get this manifold built. I have just been way too busy and so has my father in law. He is only just getting ready to start building his car. Anyway we ended up buying one of Dashman's tri-power blower tops and milling the top of the tunnel ram upper plenum down to match it's width on the plenum as the upper part curves in. I then just cut the left over 4 Barrel lugs that were sticking out on the table saw. I squared up both ends then I set the saw to a 45 deg angle and went down the sides. After I took the big lugs off I blended it all smooth with a flap disk then an orbital. There were a couple of holes where the old bolts for the 4 barrel carbs would have been left over so I filled them with JB weld as I didn't want to get them welded up. I then acid washed it with some mild muriatic acid to get the corrosion off of the old manifold and gave it a coat of rebuilders aluminum paint and flat clear. I also heli coiled all the threaded holes as most of them we buggered up anyway. I think it came out great. It will be a while yet before it goes on the engine and at least a couple of years before we run it but I think it will work great. It will be running some rochesters. What do you all think? Here are some pictures. I can't wait to have it in the car and running. I am sure I will be able to get it to perform well. Fun little project to make good use of this old manifold. Cheers. Greg
Hey a fellow cunuck! Yea you bet I will resurrect my post again when it is assembled and running. Knowing how how much time I find for projects these days it may be a while but I don't quit so I will show it complete one day. Greg
Man that is a close fit! I like it, that should work good as well. As a matter of fact, I'll be wrapping up a 4x2 Stromberg setup next week on another style SBC tunnel ram that will be pretty cool. Keep us posted! Dashman's Hot Rod & Speed Parts www.dashman.net
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