302 Hemi

[JTH74]

Would these heads bolt on to the standard 302 block or was it a completely and totally different engine?

[Leonard]

Info from: "The 1969 Camaro Reference book" by John R. Hooper. The short block was identical to the Z28 302 short block. (block,crank,rods,oil pan and baffle,timing cover,balancer,flywheel,alternator,and starter.) One big drawback to the engine was that the block had to be machined down in the lifter bore to clear the exhaust pushrods. Another drawback was that in order to install the Hemi kit items, the engine had to be removed from the car. You then installed the Hemi items and reinstalled the engine in the car... The Penske-Donohue race team had won the 1968 Trans Am season and were looking for still another "Unfair Advantage". Chevrolet designed an experimental hemisperical 302 c.i. engine with the intention of selling it as an over-the-counter item in kit form. There were actually a small number produced. These engines proved to be costly to build, but they made horsepower. The engine used different pistons, camshaft,rocker arms,intake manifold,aluminum heads,pushrods,and gaskets. The magnesium valve covers featured a 7-bolt pattern.The camshaft is unique due to the reverse-lobe design. The one-of-a-kind Hemi head has the intake valve first and exhaust second.

[JTH74]

Thanks for the reply, I will have to get that book. Did the Penske team use the hemi engine in 69?

[Charley Lillard]

Chevy shipped them to Smokey Yunick for evaluation but they never went into production or got used on Cars.