I found the slides have different mounting styles, the front set have a plate that screws down over the needle whereas the others have a retaining clip to keep a plate over the needle. Can't find my pliers to get them out :/

Sharmcos.........folks put 45 webers on A14 race engines so 41mm carbs might be ok. Either set of carbs should work well. For street CV carbs are a little more user friendly as they are slightly more tolerant if the jetting is off. As for fuel consumption I couldn't give you a real idea as my car only sees the race track............so my 15 mpg isn't much of a guage since the motor is always between 4500 and 8600 rpms.

Lowtech I was looking at the Mikuni HSR carbs before I stumbled on to the FCR carbs with manifold. My thoughts were a set of HSR carbs would be a nice up grade over then Hitachi SU style carbs.

Tom