Now the block is ready for the cam and timing set. The double roller timing set and the camshaft came from Clifford. The cam is a solid flat-tappet cam (PN 310 with mechanical lifters), and its specifications are: 270-degrees duration at .050-inch lift, and .569-inch lift, with a 108-degree lobe separation. The cam was installed at 104-degrees intake centerline. After the rod and main bearings are torqued, and the cam is in, the bottom end can be buttoned up.
Angie at MEW does all the...
Angie at MEW does all the head porting. A lot of time went into getting this head to flow with these numbers: 200 cfm at .600 inch on the intake side, and 150 cfm at .600-inch exhaust side. The valves are from a small-block Chevy, with ISKY PN 6005 springs. This should hold things stable up to 7,000 rpm.
Now we get to the good/bad part, depending on how you look at it-the head. Angie at MEW installed small-block Chevy valves with ISKY PN 6005 springs. These should hold things stable up to 7,000 rpm. Next, Angie spent some time porting, and finally ended up with flow numbers of 200 cfm at .600 inch on the intake side, and 150 cfm at .600-inch exhaust side. The head was installed using ARP studs and a .020-inch-thick steel head gasket sprayed with Hylomar. Piston-to-valve clearance checked out OK, thanks to JE designing valve reliefs in the pistons. The rocker arm system has to be able to keep up with the rest of the engine, so a custom set of roller rocker arms were purchased from Cox Brothers in Columbus, Ohio. We then found out the extra rocker arm ratio moved the pushrods closer to the block, requiring the engine be disassembled so pushrod clearance could be made. Once MEW made sure nothing was interfering with anything else, the engine was buttoned up. Finally, a water pump, a stock-style distributor with a Pertronix conversion, and a high-volume oil pump was installed, and it was off to the dyno for testing with Romeo's race carburetor and exhaust. It was quickly noted that the carburetor was running lean on the top end, but after breaking in the cam and optimizing the timing, we were pleased with 300 horses and an engine that would easily spin past 6,000 rpm.
Once the XFI system was installed, the engine was restarted and warmed up. We dialed in the XFI box, and then checked the valve lash to ensure nothing had changed. An oscilloscope was used to check the fuel injector sequencing, as well as crank reference timing, and all was good.