Engineering Diffs Between 1955 and 1956 V8s.

Posted by Joe Hall On 2007/6/2 20:19:13

The 1955 heads are lower compression, and shorter, 1/2" reach spark plugs are used, where the 56 has 3/4" reach.

The 1955 main bearing caps are less beefy, and the bolts are shorter.

The retainer for the timing chain cover seal is smooth, where the 1956 is knurled. I understand this change was made due to some of the sommth ones spinning loose. Even with knurled ones, I always drill thru the retainer and cover, and install three, evenly spaced screws and selflocking nuts. They are behind the vibration dampner and only visable with a flaslight.

Most may already know this, but the 1955s have a collar behind the cam retainer plate that floats with the cam and allows a steady stream of engine oil to pump onto the tinming chain and gears. Late 1956's have a collar that is pressed onto the cam, and only allows a squirt of oil each time a hole in the collar lines up with the oil galley; one squirt per revolution, versus a steade stream. This was one of the factory's fixes for low oil pressure.

Joe H