Quote:
Originally Posted by Cliff R
First order of business is to strip it down and measure all the "players". Pressure/leak test the casting, verify no cross-leaking between the fuel bowl and area below the DCR's, throttle plates all FULLY closed'/tightly sealed in the bores when closed, no miss-matched components installed (different top/bottom), no lead plugs driving into bypass air holes, or any bleeds or orifices made larger or smaller than the stock size over the years.
In other words it's simply best in all cases, to pretend you know nothing about the carbs history and start from a clean slate. I'll also add here than more times than not you are a LOT further ahead to be working with a "virgin" unit vs one that's had a lot of hands on it as needed modifications will be simple and predictable.
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Finally had the opportunity to tear down the carb and look for issues, but first, the history. I purchased the carb new in 1975 direct from Rochester Products. Up until this rebuild, the only things I ever did was to change jets and rods from those installed for a GS455 Stage-I to sizes that performed more effectively on my 350. Physical modifications were limited to polishing out casting lines and filling in linkage rod slots for more precise control of the choke plate. So I would consider this close to virgin, or maybe just a "First Base" date night unit.
The next event was the restoration work done which included new throttle shafts, an electric choke conversion, and rejetting for the 63 cu in displacement increase, 6X-4 head installation and use of a Comp XE276HR cam.
Upon disassembly, I noted the throttle plates all closed completely with no visible light showing around the edges and that the throttle shafts showed no play in the throttle body.
The float bowl did have some varnish/sludge in some crevices and the primary metering rods did seem to have some contact against the float bowl gasket. My concern was the appearance of the 2 brass idle air inlet restrictors. They seemed to be somewhat banged up, and I could not remember if there were originally 4 or just 2.
The four tubes in the air horn are not at the same height, one being about 3/16" shorter than the others. Pictures show these details. Considering the uniqueness of this unit, I certainly hope it is still usable.