I had a customer bring me his Edelbrock headed 496 for an overheating and oil usage issue, and to remove the solid roller camshaft and heavy valve springs to replace with a hydraulic roller camshaft.
Upon teardown several issues were evident, and some not so evident. Missing coolant holes and poor cylinder finish, along with a block that hadn’t been clearanced, and 6 of the 8 rods were just rubbing the block. The block also had main and head studs installed, but had not been lined honed, decked, or honed with a torque plate.
The owner also proceeded to tell me how the machine shop had failed to balance the crank properly and had given him external balance flexplate and dampener. It was a real shaker when he installed it. I later discovered the counterweights were not cut properly, and would not clear the pistons, and had been hitting 2 of the JE pistons. Another reminder of why I quit using Eagle products 16 years ago.
After an assessment of his parts, which consisted of RPM AG intake, 290cc Oval RPM 6045 heads (113cc), JE flat top pistons (8.8:1 CR), Eagle H beam 6.385” rods and 4.250” steel crank, Lunati 244°/244° @ .050” SR camshaft, I laid out a plan of action for some changes to improve his situation.
The Edelbrock heads received a valve job and some minor bowl work, and chamber blending. I had RaceTec make me a set of 4032 pistons with a 16cc dome and 1.5/3.0mm ring set, for a final CR of 10.4:1. A Howards Cams shelf cam was selected with Howards/Morel 91167 lifters. Cam specs are HR#120265-10 SADI core 237/243 @ .050, 289/295 Advertised, 110 LSA, 106 ICL, .373/.377 lobes, .635/.640 lift. Manton 3/8” pushrods were used with PSI springs.
I tested both the customers QFT 850 VS and QFT 1050 AN with 1” open spacer, 35° total timing on BP 93 octane with 10% Ethanol, 2” x 3.5” dyno headers. Engine idles at 950rpm with 11-12” of vacuum. The 1050 was worth another 10/10 HP/TQ over the 850VS.
This was the first time I’ve used these heads, so I was interested to see how they compared to similar setups.
498 Edelbrock Dyno Test 627HP CPMotorworks - YouTube
498 Dyno test Edelbrock Oval heads CPMotorworks - YouTube