Agree about the choke size.
We used to select total carb spec by the simple expedient of running the car on the rolling road and finalising carb tuning from there.
Despite what expectation and Urban Myth might predicate, greater power often came from smaller choke tubes. OK, I was lucky (or organised!) as I was a dealer under Chris Montagu Carburettor Company, at the time and had a large stock of 40 and 45 chokes, auxiliary venturis and jets.
That said, we also regularly turned out chokes to half m.m. size increases for optimum perormance.
All about gasflow, really. If you become hung up on sheer size this doesn't necessarily produce more power: often, quite the reverse.
That said, it is wholly pointless sporting out for mega-sized inlets and a wild cam if you are restricted to overall inlet bore size.
Back to compromise! On that note, the 28/36 DCD is of course a progressive carb and a huge compromise! OK for (e.g.) Cortina GT MKI, to which it was originally fitted, but "Untunable", basically. Stick with the twin DCEO 40s!
This was really reinforced to me by a young lad who walked into the shop one day and ordered brand new twin SU 1 1/2" and a BMC suitable manifold.
I explained, gently, that there was no way his slightly tweaked 850 c.c. Mini could suck enough! "Oh yes it can!" he stoutly maintained, "I read it in this month's "Mislead the Gullible Tuning for Minis", magazine!"
This was the same mag, BTW, that convinced another gullible young and impecunious lad to demand that we convert his 850 c.c Mini to 2 Litre..........................
And of course, back he came, to complain that there was summat wrong with the new carbs we'd sold him!
Eventually reason won and I swapped them for a secondhand set of Cooper
s 1 1/4" and matching manifold.
And his car ran very nicely!
There has to be something else, Zef.
Thinks.......................................
