Another interesting engine you might encounter in your classic Ford travels is the venerable Y-block from the early Thunderbird days. Offered in displacements of 292 and 312 cubic inches, the Y-block is different in many ways from other Ford V-8 engines. The most obvious characteristics of a Y-block are the Siamese exhaust ports on the center two cylinders and the rear-mounted distributor. Although this is the last Ford V-8 to feature this arrangement, other manufacturers have had some success with it. Another Y-block-only characteristic is the two-bolt valve cover retention arrangement where two long retaining bolts enter the cylinder heads directly through the top of the valve cover.