We're Finishing Up On Installing A 427 Crate Engine From Speed Inc And A New Automatic Tranny. I'm Going From A 6 Speed To An Auto With A Manual Valve Body And Vacuum Mondulated. Do I Have To Break In The New Engine And Tranny Before The Dyno Tune? If So, How Do I Drive The Car Without Tuning?

 

You need to let someone do a drivability tune so that it will run. Then you can break it in for a bit, and go back for WOT tuning later.

 

It really depends on how much time you want the motor to last. All out racers who only want a motor to last for a season or part of a season will put almost no miles on it before WOT tuning. Guys who want motors for the long haul put anywhere from 500-2500 miles before WOT. I did was LOnSLO said. I got mine running and tuned idle, then part throttle around town for about 750 miles. Then went and did 5 WOT passes to check my WOT tune, got it nailed in close, and then put about another 750 it w/ limited WOT blasts. Never a full run or anything. Just a gear or two.

I do hear of guys just putting one together, and adjusting a few things to make it run to and from track and dyno and then blasting on it w/ just a few hundred miles if that.

 

You can ask 10 top engine builders what they recommend, and you'll get 10 completely different answers. This is one of those subjects like "how good does "X" exhaust sound?" or "what cam is best for "X" setup?". Everybody has their own formula.

 

You do want to do a couple hard accelerates and decelerates within the first 20 miles are or so to set the rings.

Keith