RQB1600 is in the hospital having a heart transplant. I ordered a Pro-Built, Pro Series 2, 330 HP 4 bolt main block to replace the original L48 engine. I went to the shop where the work is being done, and to my amazement, the block casting numbers are the same on both engines. So, now my Avanti will have a "factory original" engine developing in excess of 330 HP. I am having the shop install a Edelbrock Proformer 2101 intake manifold and a Edelbrock 1406 carb. I guess it is time to stock up on casino chips. > BTW, the L48 is a 2 bolt main block. > > George Wendell