I recently installed an LS376/515 in to my '64 Skylark. I must say that the combination of Holley and Hooker parts made the swap virtually painless. The Holley oil pan cleared the crossmember and steering linkage with plenty of room to spare. The pan sump sits at least a 1/2" above the crossmember while still holding nearly 6 qts. of oil. The Hooker engine mount brackets combined with GM LS1 motor mounts put the bell housing and transmission in the exact location as it was with the 455. The Hooker headers offer plenty of ground clearance and actually are tucked up above the bottom of the oil pan. The Hooker Blackhearts exhaust sounds great and is true bolt in system for the 64-67 A-body. The exhaust system literally requires no cutting as it engineered to slip over and clamp to the 3" header collectors and out the back, tucked up tight with turndowns at the rear bumper. I went with the carb LS so I could re-use the Holley Terminator system I was using with the 455. All I had to do there was download the Holley EFI software, connect to the ECU, switch ignition type to 58x reluctor and change the firing order. Done.