my 1989 460 will not start cold. I have to retard the timing approximately 15 degrees, in order for it to start, then I remove the SPOUT shorting bar and set the timing to 10BTC and return the SPOUT Shorting bar and the timing jumps to 28BTC but it runs just fine. I can turn the engine off and it starts just fine when it's hot... but when it cools down, i have to do the process all over again. any advice?? thank you