The engine number suffix ID's the block as a model year '56 235, manufactured in the Flint, MI plant, consistent with its casting date of December 29, '55. The Y designation indicates that the engine was originally in a Powerglide car, so it should have hydraulic lifters, unless swapped out later. The '848 head may be original to that engine, since that casting was introduced in '56. Here's a decoder that works pretty well through '57, but it does miss some early Powerglide engine codes. '41-'57 Chevy Six Engine Number Decoder Page.

Doug

Last edited by drdoug; 09/25/2021 3:37 PM.
1947 2nd-Series GMC FC152 3/4-ton
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1953 Chevy Bel Air Sport Coupe Powerglide