Just picked up four large logo 97's in pretty good condition for 300 bucks. Needless to say, I'm stoked. My question is are four of these guys enough to supply a mild 350 or should I work towards a 6x2 set up? Also, progressive or straight linkage? Thanks
I like the adage, "if a little is good, too much is better" but it really depends what you prefer and what the engine can handle. If it's only a "mild" 350 then it probably would work fine with a 4x2 setup, but I love the look of "more" carbs myself. Also, you would have to find a SBC manifold with that kind of set up. I would go with the progressive linkage, as it will be alot easier on the gas gauge and wallet. If you are not an "engine guy" you might want to ask around a local speed shop or custom shop that could help you, or do the work for you. $.02
I think a 97 is about 165 cfm, although I am not an expert on them. So four should be fine. I don't know how you would run a 4x2 with progressive linkage on an sbc. You would need to put them in a line on a common plenum and I have never seen an sbc manifold like that. I am running 4 97's on a 283 (should be running in a couple of weeks). I just have to finish rebuilding the carbs. The manifold I have is an early rochester fuel injection manifold with adapters to three bolt carbs. I post some pictures later, the camera has a dead battery. Anyway, it's linkage is straight-up, no plenum, just one carb per two ports.
I run 4 on my 354. Works great. If the manifold will support it, definitely go with a progressive linkage. In my application I had to make a plenum box to cross distribute right with the manifold. The WC-245 was intended for straight lkage only.
They'll supply plenty for street driving. If you aren't racing it'll be fine. How you hook up the linkage will depend on the manifold that you come up with to run them. The worst that can happen is that the engine may want to rev higher but the small carbs could limit it at the higher RPMs. The hot rod 4 deuce Chevy manifolds that I've seen (1 carb for 2 cyls at the 4 corners) won't work with progressive linkage. Study the intake. If the intake does not have full size passages that lead to all the cylinders, then all the carbs must open at the same time. Adapters on a dual quad intake could be hooked up with a progressive linkage just like the dual quads if you can get all 4 carbs to fit.
Don't know too much about strombergs, multi carb set-ups (or anything else for that matter!). My other question is what to do about chokes, Leave 'em, yank 'em or other means? thanks again for the info.
4-pots aren't designed to run Progressively - and it would run better Straight Up. (but you have to get them all synced - do a search Tommy just did a good tech on this) 6-pots you can run progressive with the center two as the primaries or the outer 4 as primaries. I wouldn have to say that 4 on a stock-mild SBC would be plenty. There is a nice little equation to figure out CFM needed by a motor - any body know it off hand? Max RPM, CID, Something Something Something - I can't remember
The guiy I bought these carbs was super cool. He threw in an old original Edelbrock Uni-Syn which has never been used. the packaging is perfect. Anyone have recommendations on manifolds? I have an eye on the one in the Offy catalog.
Eelco made a progressive linkage for use on the Weiand WC4D sbc 4x2 intake (long out of production), and I have a set for my intake. If it would help you, I could copy the installation instructions for you.
It's the displacement*maxspeed*volumetric efficiency/2, and you need the conversion factors to get the units into CFM the divided by two is for a four stroke engine (one intake per 2 rev). If you can't figure out the conversion factors then you need to go back to high school. Volumetric efficiency for a good performance street engine is 80-85% or .8- .85 as a multiplier.
The old thinking was to remove the chokeplates for "more flow". Not true. It's been recently dyno-proven, more than once, that 97's, 48's and 81's run much better with the chokeplates left in place to direct a smooth airstream over the open ends of the emulsion tubes at idle, and same thing goes for the open discharge jets at WOT. This results in proper atomization of fuel, just like God and Henry intended. Strombergs love unrestricted air that's gathered from a "still" place. If you're planning on scoops, make sure the openings face rear.
I'm not so sure my high school would take me back! Anyhow, I found this chart for all of us lazy bastards: http://www.buicks.net/shop/reference/carb_cfm.htm
I went to Napa High.....and watch out for that chart, I hear a Buick CFM is different than a Chevy CFM.......
There is a SBC 6x2 set up for sale on the forum now, if you are looking. No affiliation, just found it while browsing.
Uhh it's not based on Engine Brand - based on Cubic Inches. There is a automatic calculator below the chart...just punch in 350 @ 6500 RPM and figure 80% eff. and it will give you both for 80% and 100% eff. and it says right below that Buicks like a Big Carb That will tell you how much you really need..... but you still gotta figure out how much each 97 flows??? anybody know? 175CFM??? guestimate x 4 = 700CFM which should be plenty for a mild SBC
I just read the recent post about 6x2s. It seems as though quite a few people run them. With a 6x2 how do you keep from over- carbureting or maintaining decent airflow velocity?
Hey, I've got copies made of the linkage illustration. Get your mailing address to me and I'll send you one.
i was told that the 97 only flows 145 cfm im not sure any way i was thinkin a dual quad intake with to 2-3bolt adapter plates would be cool might be perty easy to tune?
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