If I remember what Carbking taught us (if I wasn't sleeping in class again), a smaller carburetor on a bigger engine runs rich?
More vacuum from bigger pistons sucking all that gas down the hole....I guess. Okay, fun time is over.
I'm running a YF-2100 (for 235) on my 261 mainly until I finish testing some other carburetors.
Stock ignition system. Non-ethanol gas.
Compared to the Rochester B model made for the 261, the YF-2100 starts up 10X better after the truck has sat for a week.
Idles better, accelerates (initially better) and I just like it.
Last time I looked at the spark plugs they looked good.
However, it runs out of legs at higher speeds/rpms/load. Seat of the pants feel not verified with testing.
I think the excellent Carter metering system makes up for the difference in typical normal driving.
What it can't compensate for is when a bigger venturi size is required to get the A/F mixture correct on the top end.
