PJ10 PJ I own 2 shelby blocks csx58 and csx428. I have been running 58 with ahydro cam and lifters, a crane 501-533. 9.2 compression. The only machine work was the centering of the distributor in the block. Gessford was fixing this in the beginning of the shelby blocks being made. I would buy another one if I need it. The engineering is way over done compared to the other Alum motors. The head studs are bolted to the main webbing in the bottom of the block. They DON'T use the cylinder walls to hold the heads on. The cylinders should seal better from this. 12 bolts for the 2,3,4, main caps instead of 6. Larger studs in the bottom. The block is good for 2,000 hp or more. I wouldn't try that with the others. You do need someone with experience to put one of these motors togeather. Your basic machinist is not going to setup the bearing clearances correctly to cover the expandsion of the block when hot. If the motor is built correctly it will run no hotter than an iron block. You need to use the RIGHT GASKETS and SEALERS to keep any leaks to a mininium. Build a strong street motor with 10.5 compression, a .600-.650" cam hydro roller. A 484 is a real nice motor for a cobra. You will make about 550-575 hp and 600-640 ft of torque. This is about all a cobra needs and will be driviable with. This is real world numbers.
Rick Lake