Joe Curto makes an adjustable jet for the Strombergs that was most likely based on the carrier used on TR4s and possibly other engines. Here is his version (top) and the TR4 version (bottom):
Note that the top-hat piece (right hand end in photo) is chamfered and longer on Joe’s version.
I got hold of a pair of the TR4 jets and thought I’d try to fit them to the ZS carbs on my S2.
The bridge on the E-Type carb is thicker (probably needed strength since the jet is pressed in) so some modification was done to the TR4 part. The length was reduced by the amount 1 and a chamfer was added (2) to match the bottom of the E-Type bridge.
These changes were needed to get the big O-Ring to locate in the collar of the float bowl. Here is the original bowl plug compared to the modified TR4 part:
The spring was also changed as it now needs to be able to compress farther due to the greater (about 1/8") travel the jet must have to accommodate the thicker bridge:
Here are the works laid out in order except for the uppermost top-hat piece which has already been pressed into the bridge:
The copper washers were to be used to fine tune the jet height so it would be exactly even with the bridge when the adjusting nut was screwed all the way up. In the end, only one washer was needed to accomplish this.
Here’s a look at the pressed-in top-hat from below and above. It does not quite meet the bridge (again, due to the E-Type bridge being thicker than the TR4) but that should not matter as it is the top of the jet that determines the mixture.
Installed, there is plenty of room to get at the adjusters on an XK engine:
Without a doubt Joe C makes a fine product and any reasonable person would probably be happier installing his rather than futz around making a TR4 part work. But it was an interesting exercise using parts I had access to and has been successful in at last getting the mixture right on my engine.