I checked that Rom you posted on RomRaider. You were missing WGDC initial B, base timing, and timing advance max tables. I have updated that ROM with the corrections. Shot me a PM with your email address and I'll send it to you. Make sure you are using this on a stock car with a stock intake down to the air filter.
"Gimme mines Balboa...Gimme mines".....Clubber Lang - Mr. T