Quote Originally Posted by erik erikson
At or around 800 on a 400 even with all the prep work you have done is an accident waiting to happen.
It is a miracle that it has not blown yet.
We have built a few 400's,412's,420 etc. over the years.
We did the same level of prep work you did and also added deck plugs.
Every one of them ended up cracking right down the lifter valley..
I beleive you. One professional local racer said that he could never get a 400 block to take more than 600 hp. I am wondering, do you remember if you ever used a 817 block? Maybe that is the difference!

Quote Originally Posted by erik erikson
I would guess the only reason they are living is because they are in a street car and you can't hook it up.
Actually mine hooks up. I have AWD with a drag radial at each corner