Here is some info on the Mark 1 "W: head engines, to be added to the stickies above maybe?
Mark 1 "W" Series
348 Mk 1 "W" Series
348 576A 1958-61 250hp
348 573A 1958-61 280hp
348 576B 1958-61 300hp(58) 305hp(59-61)
348 573B 1958, 1961 315hp(58) 350(61)
348 577 1959-60 320hp
348 574 1959-60 335hp
348 590 1961 340hp
409 Mk 1 "W" Series
409 580 1961-62 360hp(61) 380hp(62)
409 587 1962 409hp
409 L33 1963-65 340hp
409 L31 1963-35 400hp
409 L80 1963-64 425hp
427 Z11 1963 (427 "W" Series Engine) 425hp
peace
Hog
Mark 1 "W" Series
348 Mk 1 "W" Series
348 576A 1958-61 250hp
348 573A 1958-61 280hp
348 576B 1958-61 300hp(58) 305hp(59-61)
348 573B 1958, 1961 315hp(58) 350(61)
348 577 1959-60 320hp
348 574 1959-60 335hp
348 590 1961 340hp
409 Mk 1 "W" Series
409 580 1961-62 360hp(61) 380hp(62)
409 587 1962 409hp
409 L33 1963-65 340hp
409 L31 1963-35 400hp
409 L80 1963-64 425hp
427 Z11 1963 (427 "W" Series Engine) 425hp
peace
Hog