six barrel econo Log

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First Fox":1k7zzbdz said:
Thanks for your support bubba. Multiple carbs and the turbo WILL be done. The question now is will it be two or three. I believe I will start a new post and hope for some input from Dean.

And Rich, I absolutely love your idea of swapable/removable plenums on the stock log. There is no way in the world I would attempt the log milling and intake fabrication on a log head but what youi are proposing seems quite doable for those of us without access to precision milling equipment and could be done by those if us with simpler tools and a lack if machining experience. I bet it would be a wonderful improvent in airflow as well as i believe the tiny bores use in the traditional tripower adapters are too small to flow any real amount of air. I respect your working with what you have and taking the initiative to do what youre doing. It doesnt look easy. The cavernous size of your plenum may hurt low end torque but I am telling you man, I like your idea a lot. :beer:

I've started a new post to show you all that this is possible, although mine won't be turboed for a while.

The intake I've developed is a triple direct mount 2300 series 350 and 500 cfm Holley Port On Port, Independent Runner set up. Float bowls face the rocker cover, so the throttles can turn the same way the 200 1-bbl 1946 or 300 F150 YFA Carter does.

It uses the same linkage the Colton Anderson used in his F150 truck,

I copied it, and was able to use the stock C3 auto kickdown rod.

I cut the top off the three carb choke air horns for clearance, and used the Percy's adjustajet to get cold start enrichment. The stock adjustajet doesn't go below 60 call size jets, so its a little too rich for my liking for a 165 hp engine, but I can turn the jetting from 13 :1 to 9:1 for cold starts via a special electric stepper with linear encoder motor that 64 200 ranchero showed us a few years back. When I put my tall deck 250 in , it will fit under the hood of a Fox body with ease.

If you want A/C with a turbo, you'll have to do a left hand mount like the early 64.5 to 1967 set ups.

Its on my stock 200 engine with a small log head with four 1.09" holes at 1.6875" spacings on the out side, and the inner 1-bbl intake routed out to 1.54" but with a diagonal plate. Each venturi is scavenged by one port equivalent to 1.09" in diameter, 27.7 mm.

It has only 5.60" of plenumb area at present. I can go up to 6.644 sq in, but I'm not sure if it'll crack, so Im staying with the smaller port area. The 350 cfm Carbs I'm using have six 1.1875" 30.2 mm venturis for 6.644 sq inches of total carb area, slightly more than the holes it serves fuel to. By interpolation, the Weber Independent runner chart with its 6000 and 8000 rpm recomends 30 mm venturis for 4500 to 5000 rpm at 545 cc per cylinder.

X is the cylinder size of 545 cc for our 200 cube I6's
At Y5, (5000 rpm) the extrapolated venturi size is 12.5 Ln(x)-46.8
At Y6 (6 000 rpm) venturi size is 13.9 Ln(x)-48.9,
At Y8 (8 000 rpm) venturi size is 17.1 Ln(x)-59.6
At Y10 (10 000 rpm) venturi size is 17.9 Ln(x)-58.9

The small log Offy has two 1.09 outers and a sole 1.3" diameter inner port for 1.866 sq in outers, 1.327 sq in inners, for 3.193 sq in total, and with the biggest Ford carbs, it can have Autolite 1100's with as little as 1" venturis for as little as 2.36 sq inches of carb area, or as much as 3.920" with 1.29" venturi 1101's, or 4.306 sq inches with the bigger 1940 Holley/Autolite/Motorcraft. Using three F150 Carter YFA's which are 1.4375", and can make 4.878 sq inches.

The later Offy for the D8 and EO logs has two 1.4375" outers, and a sole 1.75" diameter inner port for 3.245 sq in outers, 5.65 sq in total.kevinl0158's 29 mm venturi tri power has 3.071 sq inches of venturi area.

With just the early log head, I have 116% more carb venturi area than kevinl0158's, which drops the air speed down to the ideal for maximum power. Its only 59% more area than Ford Sedan Deliveries.

The best hp reading with the big Offy log is what I recon to be 181 flywheel hp with kevinl1058's T5 manual Triple 34 throttle and 29 mm venturi Weber 1-bbls.

FalconSedanDelivery got about 220 hp flywheel with his auto 250 comprising the big bore 1-bbl 1.29" venturi Autolite 1101 and 1904 Holley carbs he used for 3.920".

I've used the smallest log head because it has given me a 12.7:1 compression ratio, and I'm using M110 Twin Cam Mercedes Benz valves with 1.80" and 1.42" exhaust sizes, with a very restrictive 0.433" exhaust valve guide. Total lift is now 480 thou via offset bushes in the stock adjustable 170 rocker gear. Fitting the valves and springs has required major FE style rework of the pedastools and pushrods.

Cam is stock US 256 degree, which is similar to the cross flow cam that made maximum power at 4400 rpm in the 2-bbl 3.3 Falcons with just 455 thou lift.

I've still got to get this lot certified for road use, but its almost finished.

I am able to transfer the set up to the large log EO head I have, and it allows the triple carb throttle body to be used as an port EFI manifold, and the injectors can be fitted to the outer part of the log.

Its very simple to do.


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Man, how in the world did this post elude me all this time. Thanks for the excellent info as always, I will have to reread it a few more times as the numbers are overwhelming, also as always. :beer:

I actually started mocking up my homemade triple/mod log intake intake a few weeks back but wafter seeing thia post i am again motivated and will be messing with it more this weekend. In typical First Fox fashion, I will be using what I have in a scrap pile if at all possible and it will be ugly as sin, but it will work.

Thanks again X. :beer:
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