i have 2 of the newer ford boss 351 windsor racing blocks. they are no where near a standard winsdor block. 351w boss block > splayed 4 bolt main caps on 2,3,4. cleveland size main journals. screw in freeze and core plugs. high nickle content. high lifter bores for tiebar lifters and standart base circle roller cam. oils both lifter banks from the front at the same time. its a super strong block.