I was looking at my spare BBS carbs and noticed that one of them has a noticeably larger venturi/bore/whatever than the others. Is that worth rebuilding for a couple more HP for my 225 stocker?

Is the smaller one really meant for the 170 engine? Would they both use the same rebuild kits? Thanks.

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'63 Valiant V200 Convertible
225 Aluminum Block

There were actually many different sizes of venturi and two different sizes of throttle bore for the BBS (and for the Holley 1920). The 170 through '66 and the taxi/fleet 225 got carbs with a 1-9/16" throttle bore and a small venturi. The regular 225s (and 170s after '66) got a 1-11/16" throttle bore and a larger venturi. Trucks got even a larger venturi, still with the 1-11/16" throttle bore. The same kit is used for pretty much all of the BBS carbs, but pay careful attention to the gaskets you select from the kit, because the kit contains more gaskets than any one carb needs, and some of them have different central bore sizes. Match up the gaskets to your castings to make sure you're using the best-fit gaskets.

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Too many people who were born on third base actually believe they've hit a triple.

Not sure about any other years, but 65 Valiant 170 standart shift got the small Holley 1920, and the auto trans 170 and all 225's got the large Holley 1920. This pertains to the engines that had the Holley carb. Do not know if there is the same difference with the BBS.

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Charrlie_S
65 Valiant 100 2dr post 170 turbo
66 Valiant Signet 170 nitrous
64 Valiant Signet
64 Valiant 4dr 170
64 Valiant 4dr 225

Sounds like the larger bore is the correct BBS carb for my '63 225. I'll rebuild it, install it, and report back. Thanks for the good info SSD.

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'63 Valiant V200 Convertible
225 Aluminum Block

Finally rebuilt the carb and installed it Saturday. I can't tell if it actually produces more power by the seat-of-my-pants but I think, overall, the engine runs better with the bigger bore carb. The kit included gaskets for both size carbs. The fuel inlet valve was longer with this kit so I used a shorter one as I couldn't seem to get the float right with the longer one.

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'63 Valiant V200 Convertible
225 Aluminum Block