Is it worth it?

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Grasshopper

Grasshopper

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As a fan of the slant 6 I have been thinking of converting to the super 6 set up. The parts are hard to find. I think I just need intake manifold 2bbl carb, throttle, and kick down linkage. Not sure if I need anything else. If I am able to do this what should I expect in performance?, gas mileage?
What year cars should I e looking for with this set up to get parts? Thanks!
 
There was some in parts for sale a little while ago. IIRC something like $600? I often wonder if it's worth the outlay myself. Going to eventually upgrade to a v8 car anyway.
 
Appears like 2 bbl setups currently sell for ~$200. The days of finding them in junkyards for $25 are gone since too many people know the demand. Too pricey for me. For ~$500 you can get an aluminum 4 bbl intake which saves much weight and allows more options. I suspect a 2 bbl would lower mileage over a 1 bbl. A small 4 bbl could conceivably do better if the primaries were smaller than the 1 bbl, but I don't know of any spread-bore 350 cfm carbs. With a 4 bbl intake, you could mount something like a Holley Pro-jection or Motorvation (and others) TBI. If you could find really small injectors, it might fit a slant. The later is better since it uses common MPFI injectors, which come in more sizes. Myself, I am planning a home-made MPFI manifold setup. That would give the optimal fuel distribution.
 
You will also need a 2 bbl. air cleaner.

The Aspen and Volares, had Super Sixes and I think some pick up truck, early Miradas and Diplomats I think.

MY seat of the pants dyno says my 75 Valiant runs a lot better. I imagine I'm getting better gas mileage than the 1 bbl. Holley that was on there.

Keep your eye out on here and Slant Six .org. There are still honest people out there that aren't trying to retire by selling you a super six set up.
 
...Look at the specs, Super 6 had what, like 10HP and 10 ft/lbs over a 1bbl? They did it to compensate for all the smog crap that got instituted at that time. I would say not worth the going price:
Get a super six sized headpipe (2.25 instead of 1 5/8 of a 1bbl slant). Do the HEI upgrade on the ignition. Regrind your cam for $50 from Oregon Cams and get yourself a few degrees of duration and lift. OR ghetto rig a 1bbl intake: Get yourself a 2bbl carter/stromburg to 2 bbl Holley adapter for a nice base to attach any 2bbl to, drill an outline of the adapter into your 1bbl intake with a series of 1/8 X close holes so as to put the barrels parallel with the valve cover and the throttle lever on the side or toward the rear. Use a hammer to break the shape window out (really) Epoxy or weld (if using an aluminum intake) adapter onto intake and seal. get yourself a 2bbl carter off a 318 or a 2bbl Holley off anything else. Mount it up. Bend or use the 1bbl throttle bracket to attach cable to new carb. Kickdown can be cable operated: either a puller or a pusher setup. Puller, run a bike brake cable from the top of the carb throttle arm or any part that pulls when the throttle is actuated. Anchor sheath with some sort of bracket (you can use large brake line and put a pinch in the end to capture the brake cable so you can guide it in a rigid sheath) then route it around the back of the trans and hook it to the throttle pressure/kickdown arm. Usually you can just wire up full throttle up top and see where the cable ends up, then pull the kickdown lever back as far as it goes and mount the sheath it so its at full kickdown at full throttle. You can adjust it by pulling the sheath through its clamp usually mounted on the trans pan bolts. Like a shifter cable but coming from the rear. Pusher- Shimano (bike equipment maker) made a lightweight push/pull cable for a certain gearshift (Positron) that was a rigid cable in a sheath. IF you could find a push pull cable like that, you could put it in a small rigid brake line and bend it up so it literally pushes back on the kickdown lever just as a mechanical rod would. It would have to be supported so it doesnt flex any but you could literally bend it all over the place as long as it had sweeps as bends and ended up pointing straight back to the kickdown lever. Looks like a boat throttle cable would be good but a bit heavy, but $12 bucks cheap for a true pusher cable setup sitting right next to the throttle cable up top.
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2bbl is supposed to get a few MORE mpg's than a 1bbl as the velocity is greater through 2 smallish bores rather than 1 larger bore, but dont expect Feather Duster mileage without all the other feather stuff. I have no real world mileage data.
 
I've tried the 1 bbl vs 2bbl thing with my dart and the 2 bbl definitely out performs the single bbl holley. I used an Offenhauser 4 bbl manifold with some home made adapters so I could run a 1920 Holley 1 bbl or switch to a Carter bbd 2 barrel without changing manifolds. The Carter 2bbl gave better throttle response and had more top end power, the Holley 1bbl just kinda "runs out of steam" over 3k rpm, both carbs were in good working order. The mileage actually stayed the same between the 2 carbs. I would much rather drive a slant 6 with a 2bbl carb than one with a single bbl carb.

Just my two cents..
 
Go with the holley 600cfm 4bbl vacuum secondaries. It's like putting a 6-pack on a 318. You can get anything you need to tune a holley or rebuild it for cheap and you will never run out of carb with vacuum secondaries. I drove mine up 81 from Harrisburg PA to Syracuse NY at 75-80mph and got 27mpg.
 
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