Offy Tri-Power

I just did some ciphering and calced out that the 200 wants about 300+ cfm to peak at 4500-5000 RPM so the 32/38s are just right at 85% VE. (Don't care about top speed. Just want to smoke some ricers.) That has no putter-factor; you just bolt them on. Real men want to use tools and all, you know. On the other hand, the ICHs are off the scale if you get 3 with the tri-flow header: $650.
Three 1100s at 185cfm are way too much for a 200. Two would be better. Maybe I could mill a dedicated mounting plate from aluminum, but this is a lot of work with a twist drill. Soo...
I'm thinking about 3 of the early one barrels with the 1 and 7/16 throttle bores flowing 130cfm times 3. I'd be in the range I want and it would be all Ford. Any used ones laying around? Boys?
Am I off the track?
 
I thought about using the early 1-bbls too. The issue is what to use for the vac advance. The early 1-bbls have the spark control valve (as far as I know) and that they don't have enough vac to properly feed the cannister on a later, dual advance dizzy. If you keep the load-o-matic dizzy then again the quesiton will be: is the vac signal from the center carb "correct" or the right level to keep the dizzy advanced to its best/proper operating point? just some points to think about. And you are correct, from a flow point of view the triple small carbs would be best.
 
I have a small and a large vac outlet on the manifold below the carb. I know this is not the right one for vac advance unless the tri-flow would attenuate the vacuum adequately. Could this run to the vac advance? On the other hand, could one disable the spark control valve and tap the trroat down below the venturi, then yoke them at a "vaccuum manifold" to get a total vaccuum to the dizzy?
My other choice would be some Jeep Solexes or VW carbs.
 
I have the single vacuum advance right now: stock 66 w/ Pertronix. I'm thinking about going to a DSII, but the recommendation elsewhere is for a single vacuum advance, not dual. I think it would be the same deal as my present situation. Advice?
 
Well a couple of things:

Why not a daily driver. not saying you can't. SOme people have had great success. It's just I drive 100 miles a day in my car, which many people do not use an old car for this. Also, my wife drives this car. So I had to re-evaluate that I needed and wanted. I want simplicity, and the offy is anything but that.

I did run a choke on the center carb. Not sure how helpful this really was since I never ran this set up in cold weather.

As far as power band. There was a little increase at low end, only because the outer carbs were letting some fuel and air to get better mixed for the outer cylinders. The increase was minimal though. I personally think that Offy gives a lot more power up high. But overall, it did give more power over the entire range of RPMS, just most of it was above 3000 RPM.

For a fuel system, I actually tracked down a 289 Tri power fuel log. It works great, though can be pricey (around $100-150). it has one inlet, and 3 spaced outlets. It even has mounting brackets that can be made to work well with the offy manifold.

my hood clearance issue had little to do with the carbs, and more to do with the type of air cleaner I wanted. I used an oval 3x2 air cleaner, so I needed a little more clearance.

If you are worried about too much CFM, don't worry, 500 CFM isn't really too much. Some people here are running as much as 600 CFm with no problems. It really matters how your engine is set up. If you go enlarged valves, high lift cam, and the Offy...you engine will do well with 450+ CFM.

Slade
 
Looks like I started something here. :)

Mugsy, are you saying the Offy is built for the carbs used for the particular year?

If I order an manifold for a '66 it'll come set-up for 1100s? If I order a later '69+ manifold it will come set-up for a different carb?

I was planning to get a later head for the bigger intake log, bigger valves and hardened seats, but I already have two 1100s.
 
What I am saying is that the '69 and later adapter has a larger center pad for the carb. The center mounting on my adapter for a '77 250 head is the same as the stock carb. I think its called a YF. I have never seen an earlier adapter but with people saying they basically used three stock carbs that means for heads before '69 the center mounting is for the "small" base carb.
 
So what carbs would you guys suggest for a triple carb setup?
 
I like the 1100's, had Holleys (still do someplace) and hated them mainly because they loved to flood and I was always trying to adjust the float level and dumping gas everywhere (float bowls are side mounted)

I have a mechanical advance Mallory distributor so I don't have to worry about vac. advance.

Also I found a manual choke 1100 with dual accelerator pumps and run that for my center carb, I removed the chokes on the outer carbs and made brackets for small return springs and mounted them where the chokes had been.

See Ya,
Mike
 
You may have a hard time finding manual choke 1100. Or they may be real expensive. instead, get the automatic choke 1100, and just remove the choke mechanism on the outer carbs. cheaper, and just as reliable.

Slade
 
So with the choke on the center carb, the butterfly on the outer carbs stays open, right? And the air entering is just restricted on the center. Or does the throttle plate on the outer carbs remain closed on startup and open as the accelerator is depressed?
 
the outer carbs stay closed until you give it gas and the progressive linkage opens the outer carbs.
 
One question: at what angle of the center carb throttle plate does the outer carbs start to open? I am used to Quadra-Jets and the secondaries open at about 60* open of the primary. Any opinion guys?

tanx,
Mugsy
 
ludwig, you just remove the complete choke assembly from the two outer carbs including the shafts and plates.

mugsy, I don't know what angle the outer carbs open (if you really need to know I can find out) but the way the arms on the linkage are designed the two outer carbs are shorter meaning they open quicker once they start and all 3 reach WOT at the same time.

See Ya,
Mike
 
yeah, you want to adjust the linkages so that all three are WOT together. I think that means the outers come in at approximately 2000-2500 RPM.

Slade
 
And now, how about adjusting the fuel mix and the other little adjustments you need?
 
My plans are to install a wide band O2 sensor in the header collector. I'll use that information to set the jets, etc. I also know that Dyno shops will put a sniffer up yer tail pipe and see what's going on. I found a very impressive machine/speed shop about a mile and a half from my house that has a dyno. The shop manager who was showing me around specifically mentioned that they sniff for O2 during the pulls. Don't know about the cost, but I will be checking it out this sumer.
 
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