Mike,
There are some emission 40DCOE
Webers where the idle bypass circuitry is fixed and cannot be adjusted. These are a PITA according to Hammill.
All the 40DHLA Dellortos I've seen (off Alfa 2000s) have screws so you can shut this feature off. But Hammill says it is handy to have this adjustment as you can better equalize idle mixtures.
Main other difference compared to early (desirable) ones is they have more bleed holes in the progression circuit. So progression from idle is a bit leaner.
Hammill does say on p9- "No competition engine should ever be equipped with an emission type Dellorto or Weber 40mm carburettor"
Take out the cover screw for the progression holes- if it has 2x or 3x 1.0mm holes in there it is the early type (GOOD!) if 5 larger (2.0mm) holes it's an emission carb. Not as good...
This doesn't mean you can't use them though. Cheap to buy and try...
My Dellorto is just marked DHLA 45 and has no bypass circuits. Dunno what it's off..
<re-edit> , 'coz I f**ked up the numbers..
Dellorto DHLA 40 `C' and `E' are pre-emission, but the F, G, H, L & N are emission ones according to Hammill.
Best one is DHLA 40 (no suffix).
With Webers, he says 40DCOE 11 and DCOE 2 are the ones to have.
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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.
