After doing many later model "R" Jaguars, we have also recently boring throttlebodies for the supercharged 4.0 X100 and X308. The above pictured throttlebody was bored from 75mm to 83.4mm and rebuilt with a custom made butterfly.

 

awesome, have you done any testing on the performance gain? any ideas on cost and potential driveability issues?

 

Not on a stock car, but on twin screw cars they provide a good gain by reducing inlet restriction. Cost is 400 and no driveability issues to report. I actually have a bored TB now which I'm selling for 400, if you'd like to try it.

 

Since the TB pictured above is from an AJ26(97’-98’ XK8 and 98 XJ8/R), have you done one on a later AJ27?

 

Not yet, but will be doing one in the next couple weeks. Will be the same process and expect similar results.