I apologize if this is an old question answered many times.....I've searched but not found the solution. I have a rebuilt 223 modified with the 300 distributor with mechanical and vacuum advance. Was working just okay (except that it was gasping for air during accelerations) and then I replaced the stock intake and ancient Holley 1bbl with an Offenhauser 2x1 and two replacement 1904's (the Daytona Universal Replacement replicate of the Holley 1904). Having troubles dialing everything in since.... One issue and one concern.... Issue: currently the vehicle bogs at acceleration. I rechecked compression and adjusted valves, re timed w/o vacuum advance, and then re-attached advance vacuum attached to manifold. Idle seems smooth though slightly higher than stock spec. Checked carb accelerator pump on forward carb and see no acceleration pump discharge though I hear it "functioning". Concern: The Offy intake has a single manifold port slightly rear of middle between the carb mounting flanges in the log portion. I have 3 take offs from that port....one for dash vacuum gauge, one for the power brake mod, and one for the 300 dizzy vacuum advance. With the distributor vacuum line disengaged and a vacuum gauge in it's place the gauge needle rapidly bounces between ~15 and 20. Is this an artifact of the 2x1 log intake? I've rechecked timing and it doesn't appear to be late. Question: with 2 "1904"'s have I halved the air flow at idle and thus disrupted the accelerator pump function?
So it turned out that one of the new carburetors was assembled in such a manner that the metering block was not sealing against its gasket inside the float bowl. Neither the accelerator pump nor the idle circuit were functioning. After disassembling and reassembling the carb all of the mysterious issues went away and I've been able to properly tune both carbs. In the process of troubleshooting I also found the low RPM mechanical advance springs on 300 distributor I installed were not allowing advance to occur until RPMs were around 1200 or so. I plan to swap that spring out to get an earlier mechanical advance. Vacuum advance is hooked to manifold and the engine seems to want more advance than it's currently getting. Still have a flat spot coming off of idle, but once the RPMs are up the truck just wants to take off. I'm thinking the additional mechanical advance and some tweaking on the accelerator pump linkage will help the flat spot and will be trying that next.
Does this manifold have the ports for the heater hose hook up? Check with the guys on Inliners, but I think you need the water hook up to preheat the fuel intake. This might help with the stumble We ran a single two barrel on our race 223 but we were WOT most of the time so the pre heat was not needed...
No, it doesn't use water for pre-heating. It mates to the exhaust manifold as the stock intake does and is warmed by the exhaust flow from the internal exhaust valve. Posted using the Full Custom H.A.M.B. App!
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