Quote Originally Posted by RogerH View Post
I note from programme entry details that some of the YB engined Escorts currently have a capacity of 2400cc - I am no expert with these engines but I understand the YB came out in 1986 and had a standard capacity of 1993cc. Under T&C regs a re-bore is allowed only for Groups 3 and 4 cars and only to 0.060". As the Escorts are 1970? configuration they are Group 1 so no allowable re-bore unless it can be shown that in 1970 such a capacity was available as a " … specification of its original build …. or …. modifications that pertain to that particular build ….". Maybe this is an issue?
That is not correct. Group 1 and Group 2 under T&C are allowed 12.5% increase in CC - Group 3 and 4 only 0.060" (or 1.5mm). So a 1993 + 12.5% = 2242cc so if over that still outside the T&C rules.