Ok I have just installed my new engine in my bird. 89 Formula TBI w 700r4, Right now I have 3.42's in the end but I am thinking about 3.73's would this be too much gear for me or should I stick with what I have now? Engine is a 355 with a compression ratio around 9.8:1 crane power max 2040 cam I think, Lift is 450\454. Headers with 3" exhaust going into a flowmaster, 454 TBI w\ 65 pound injectors ported intake and heads, 1.6 crane roller tip rockers, msd 6a and so on and on, Right now I am crossing the traps at about 4900 to 5200, best time with 3.42's is 14.20@96.23mph, I am worried about my car slowing down with 3.73's, can ya tell me what ya think? Also if I do go with 3.73 getting my speedo right shouldn't be a big problem, but someone tell me if I am wrong, I will need a 15 tooth drive gear and a 45 tooth driven gear RIGHT? I know if I don't put my tire size down someone will ask street tires are 245\50\16's Slicks are 26" 10.50. If ya need more info please let me know. Thanks alot


BTW right now I am shifting around 5300 to 5600.

 

anyone?

 

hummm thanks for the help

 

To tell you the truth you will probaly not notice a real big difference. Are you only going to be on the strip or mainly the street. I would put 4.11 in if I was going to be on the strip most of the time and not take very long road trips.