1000 cfm on 470 ci ??? Seem a bit large IMO but,
Try it with the throttle linkage and vacuum advance (if your using it) disconnected . It would also be a good thing to verify your timing mark is stationary while this is happening
Also make sure your secondary blades are not moving (Long shot).
Check the
gasket and screws between the baseplate and main body. I've been bit by that more than once
If using one of the soft paper gaskets you should be able to see the imprint of the baseplate on it.
that'll keep you busy for a bit
keep us posted
No vacuum advance hooked up. Timing does not move.
Screws are tight, gaskets are new.
Base plate gasket does has imprint on it. It was new as well.
With that information I would go back to the carb.
1. what is the history on the carb??? New / used
2. Not sure if that carb has a 4 corner idle or not ? If it does try completely closing off the rear screws and adjust using only the fronts. See if it improves.
3. Repeat the process closing off the front and adjusting the rears. It may help isolate which side is having the problem.
4. Only other things I can think of are
1. the cork seals leaking around the mixture screws. 2. wrong metering block gaskets 3. Wrong base to main body gasket
5. Carefully dismantle in inspect it, the gaskets and all the mating surfaces.
I would use compressed air on all passages making sure they are clear.
Reassemble and try again.
or put the 850 on and shelve the 1000 ( a bit of humor
)
Keep us posted
