All Small Six Marine Rochester Mercruiser 2 Barrel Carburetor on a 78 200 D7 head

This relates to all small sixes
7

78_200_C4

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On the first drive it wound to 5,500 in low then pulled hard when in 2nd with a C4 + 3.25 gears.
Cam is a stock Enginetech 256. Head is milled .060
I haven't been able to test the C4 GV overdrive 6 forward gears yet.
I'll do that on my 2 favorite uphill I-80 on ramps.
The carb is a large base large venturi Rochester type Marine 2 barrel.
It only has one idle adjustment screw and no vacuum ports.
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It hauls @ss on I-80. In 3rd over at 85 mph + 3.000 rpm over it mows down any I-80 hill without shifting down or adding more throttle angle.
Today there was so much traffic on I-80 that I went in and around all the new cars until my 63 4 door 6 cylinder Falcon wagon was leading the pack at 85-90 mph.
 
Excellent engineering on your carb. I have been very interested in the Rochester and Carter BBD. And awesome cold air setup, looks NASA related with that insulation.
I-80 is perfect for high speed testing. I get a kick out thinking what BMW owners and such reactions are to the Falcon wagon tearing along like that.
Hope you post more videos.
 
interested in the 2Bbl adapter - looks like you formed it with epoxy?. Howd' ya do it?
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On similar 2bbl mod, trying to retain the 3-1/2 degree angle on the carb base to head/manifold to use Holley 2300 series 2 Bbl carb with float toward VC not over headers.
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with non heat rated angle adaptor from 3D printer file:
.. .
. to replace current 2bbl adaper:
. .
any suggestions appreciated ...
.

thanks
 
The adapter is 1/8" steel plate top and bottom. The sides are 3/4" angle steel.
The JB Weld epoxy was used to smooth my lack of tig welding skills with my old Harbor Freight tig welder.
I barely used any filler rod.
The D7 large log intake bore was enlarged with a carbide bit in a die grinder.
The intake was not milled, brazed or welded.
Adapting the air cleaner to the large base Rochester was as much work as the carb adapter but it turned out great.
The Rochester Mercruiser 2 Barrel Carburetor has the same size throttle bore and venturi size as the 500 Holley 2 barrel.
The 1 + 2 barrel 500 cfm rating is around 353 CFM at the 4 barrel rating.
This carb is not too large for my 78 stock cam 200 with an enlarged intake throttle bore.
With a new Lares 16-1 steering box I can do 80 mph on I-80 curves as I pass the new cars.
The new Lares steering box was around $230.00 when I bought it.
 
(y) (y)
Rochester carbs have excellent engineering and can not be beat when set up right. The triple venturi provides excellent atomization= snappy power and good economy.
 
I took it for a test drive after replacing the HEI vacuum advance.
I shifted to first over at around 5,000 + then shifted to second and let off the gas.
After that there was this slap, slap, slap noise. I had never heard this noise before.
I'll replace the 3.25 gears with a new 3.50 ring, pinion + posi rebuild kit.
The 3rd member C20W 4025-F is from a 1963 Mercury S-33.
I have been running it for over 40 years in 2 different Falcons in a 66 Mustang 8" housing.
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The pilot bearing surface diameter on the pinion gear was worn a good .010 along with the pilot bearing being visually in very bad shape. The other bearings looked good. The pinion gear bearings still had a preload on them.
 
The new 3.55 gears + posi are great with the 6 forward gears provided by the C4-GV overdrive.
I drove my daughter's 1960 4 dr 283 Impala while my Falcon was taken apart.
That old 283 with a small base 2V Rochester carb. and HEI distributor started right up and ran + idled great every time I drove it.
It ran so great that I downloaded "See the USA in Chevrolet by Dinah Shore".
 
78_200_C4 said:
The new 3.55 gears + posi are great with the 6 forward gears provided by the C4-GV overdrive.
I drove my daughter's 1960 4 dr 283 Impala while my Falcon was taken apart.
That old 283 with a small base 2V Rochester carb. and HEI distributor started right up and ran + idled great every time I drove it.
It ran so great that I downloaded "See the USA in Chevrolet by Dinah Shore".
Click to expand...
Since your posting I've looked at those carbs. Would really like to get back to a Rochester 2G of some sort on the 240, but I need vacuum ports.
 
Really have got interested in the R2G. Looked at a couple on ebay that looked rough but I suppose are rebuildable. Might be a place to get a rebuilt like Mikes Carbs. Want to get one now because they can only get more scarce. Interested in the small base unit. Think it will work good on my Bronco.
 
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