well, i'm seem to have gotten a fairly decent discussion on this topic. the reason i started this is, that i'm building the Model King Ford F-350 and the kit motor to that thing stinks. i am putting the 32 ford kit 302 in the truck. i thought that was a decent looking small block. as for the cleveland windsor thing, never seen a cleveland engine in a Thunderbird. the cleveland was only made from 1970 thru 1974. it was also a bigger block than the windsor. windsor heads Will fit on the cleveland with a little waterjacketing but, it takes a special intake manifold that i don' believe is made anymore and are very expensive. this is how the Boss 302 came about. 351 cleveland block + 302 windsor heads = Boss 302. as for the Thunderbird, all it ever got was the 429 in the late 60's and early 70's and the 351 windsor from 1975 on. thanks fellas for the info.