Quote Originally Posted by bonespec View Post
Limited info I've gotten back, 4.7 vs 4.9 becomes a tradeoff on which corners are in "the wrong gear"....it is a tradeoff.

4.9 Civic/CRX works at ORP and Mid Ohio.

IDEALLY (deep wallet!) you should have both depending on the track and driver. But I'm sure everyone can afford a spare $2000+ tranny just to test a different FD ratio.
There is an easier solution now that IT rules allow cars that have 14" OEM wheel diameters to run 15". I chose a 4.929 final drive (GEAR-X). At small tracks I run my 14" wheels (225/50), while at large tracks (only Road America for me in the Midwest) I run 15" wheels (225/50). With the 15" wheels it is the equivalent of a 4.723 final drive, perfect. This is the B18A engine, so my choice may not be perfect for your application, but the idea is the same.

This did produce some fender clearance issues for me in both the front and rear, but nothing that wasn't resolved with some custom fender rolling.