Weber serial number questions
 

I have a few questions about the serial numbers on the webers. I have two setups, one set are 40IDA 3c1's and the others are 40IDTr 3c1's. What is the difference in these two setups? I have looked at a couple of Weber books and cant find the IDT's. I am guessing they are later manufactured carbs? Also any sugestions on venturis, chokes and jets for a euro '80 911sc? thanks guys i appreciate it. :)

For all intents and purposes, IDA and IDT carbs are the same. The IDT carbs were fit on the '68 and '69 911T models and had a different idle mixture screw setup (to assist with emissions I believe)

That said, venturies, jets, and emulsion tubes are all interchangeable between 3bbl IDA, IDS and IDT carbs.

Regards,
Andrew M

Webber 40's
 

Andrew is correct, the three barrel 40 carbs are virtually interchangable when used other than on the original cars.

The IDT's (1968 I believe) have a pair of vacuum ports on the manifolds for US emmissons - which are just plugged if used on other engines.

Bob