Hi gang, time for an update on the build and a request for some gearing advice. The build is progressing along fine, Larry is well into completing the body and chassis and George has the motor configuration set. Motor build webpage:
http://www.gessford.com/cobra/images/BAU-427.htm
Here are the changes to the build since my post mid October -
12/19/10
WHEELS -
Style: Schott Sprocket
Front: 18 x 9.5"
Rear: 18 x 11.5"
HUB CENTRIC - Outer Hub Boss Dia 2.5000" (front/rear)
These rims will also have an "even" outer dish dimension of 3.5", front & rear.
MISCELLANEOUS -
Roll Bar: Two 3-point loops (driver & passenger), now race legal.
Gauges - Stewart Warner "Heavy Duty", Smith doesn't have the full compliment I want in a specific series, oh well.
I also replaced the clock with a vacuum gauge, still 10 gauges total - but all business now.
Now, some gearing talk. (Larry & Richard, please chime in if you're reading). From the BOM on the motor build page you can see George has me setup with a TCET4617 TKO 600 (.82 5th) Road Race Transmission. Assuming my tire diameter will be ~26", and that I'm expecting ~400 RWHP, does the 3.73 rear end really make sense? I've run some numbers through this on-line gear calculator:
http://www.5speedtransmissions.com/gear_calculator.html
As you can see, with a 3.73 at 80mph I'm taching 3163 rpm. With a 3.31 @ 80mph I'm at 2807rpm. I like taller gears generally and want good gas mileage for cruising/long trips. I think with the power I'm expecting along with a car weight ~2250 lbs, I don't see a problem here. I'm also the 1st to admit I'm an idiot with this stuff, there may be other ramifications I'm totally unaware of. My driving preference is I DO like extreme speed as well as handling, and the pavement in my area is real good (like glass). When I take a cruise on my BMW K1200S sportbike, I'll find a way to run it up to 160mph every time. I know a 3.31 has a better high end, but it has to all work together as designed. So there's the question, you guys with the experience let me know if a 3.31 rear end will be a problem (from any perspective), or if you think it's ok. Any advice would be greatly appreciated, thanks.