I HAD MY 4160 BUILT AT A SHOP IN FRESNO CA. SPEED-ENG.COM THEY CHARGED ME 1500 FOR A COMPLETE REBUILD, I PUT IT IN MYSELF. IVE HAD NO PROBLEMS WITH IT. MY BUDDIES HAS THE SAME TRANNY AS ME AND HE HAS A 408 STROKER WITH A 200 DIRECT PORT AND HE HASNT BLOWN IT UP YET