i have ran this motor in my mavrick flawlessly for 3 1/2 years now and broke a wood drift key that goes in the crank sprocket. originally, i had installd a cheap summit ($39.95) doubl roller chain which appeared to have strechted after the long drag strip srvice. i then installed new keys from Lem in the crank and also a billet roller chain from summit $98.00, with the 9 key way adjustable retard/advance and when restarted ran like a dream at the shop. loaded the car uo into the trailer and got to the races friday night and the car was shooting flames 2 feet long out of the exhuast and poping a cracking real bad, could not launch the car and babyed it down the trACK AND BACK TO THE TRAILER. i believe now that i have broken another key and i can't for the life of me figure out why. while replaceing the old timing chain i went as far as pulling the intake and the cam, checking everything from the roller lifters to the pushrods and also done a compression test which was OK. the cam spun freely in the cam bearings, any thoughts?