Hi. I ve a B18A with also only one ZS175CD carb (probably you have the ZS175CDE, the same plus emission gadgets). Our carbs provide less hp than 2 SU (or 2 ZS), goes only up to 140 kph speed, but, on the money side, it uses only 80% of gas for the equivalent millage on 2 carbs engines. Your call, speed or economy (high octane gas are not cheap anymore).

In my car I've a C camshaft. Bit of change: my idle is near 900-1000 rpm (no less or die), but I ve a bit more torsion (power) at middle speeds. C camshafts works fine with 2 carbs.

Also A cam help a lot on low speeds (like driving into a public garage).

You can adquire a C from IPD and other sources (like CVI), but adquire it with new lifters and pushrods (a new cam with old lifters and pushrods will be come a eated-lobes cam on few time) and use cam lube t assembly time. D cam is for injected engines. On Sweden many new A cams are available (many one carb amazons are on Sweden), suggest contact one with internet sales for it.

If you want some more agressive, the IPD (and other makers) "street" cam will be help you, but also need change to two carbs on that case.

One carb was designed for european economical concious people, two carbs for speedy sporter americans: the B18 with 2 carbs was called "The American Engine" on its time.

Hopy it helps, happy volving,

Joaquin
Rojo 121 Amazon
Lima Peru