Nothing to stop him.
As I remember back in about 1998 GTS was set up as a catch-all class for cars that did not meet IP or GT class rules and as a second run group for both. IP cars were required to be entered in the IP class at the same race meet to be able to run in GTS. These rules also allowed two drivers in one car which increases entries. The requirement for all GTS cars except IP as noted above to have the full GT safety equipment came a number of years later. There was never any intent to try to equalize the cars. It is a simple displacement based class breakdown. CACC has GT and IP for people who want to race against a more or less equal car within the rules.

Jordy Isaak wrote on Oct 22^nd, 2011 at 8:01am:


I guess what people fail to see is that if a person was so inclinde they could now add a engine mod, and run slicks on there IP car in GTU, GTM, GTO.  Now that car is going faster with IP safety requirements.  

I could go either way on this issue and could piont out that an IP1 Corvette that runs 1:15 already has less safety requirements than a GTL car running 1:18's

I think the main group of people this is for would be the cars that have failed to comply to our current class prep rules due to one reason or another, whether on purpose or not.  It also allows a GT car to run a cheaper DOT tire instead of a SLICK

Jordy Isaak wrote on Oct 22^nd, 2011 at 9:14pm:


YES , it seems I was wrong, Did not look down far enough in the CACC rules

Improved Production cars entered in GTS Category
A. To allow CACC members an opportunity to compete in GTS category as an additional entry, cars whose logbooks states the car is an IP category car may be entered in GTS category.

Race Competition Regulations

17-2 1/1/2011
GT Category
Cars so entered need only conform to the vehicle safety standards required of IP category, provided that in all other respects, the car complies completely with IP category rules.

And I guess I have not looked at your Dads car in some time to see the correct engine was reinstalled