[Darren69]

Originally Posted by iainw

The monster and ST4 have the Bassa heads as explained by Nelly.
https://www.youtube.com/watch?v=Dzw31m3gdZ8

Thanks for that. Interesting; he mentions the front exhaust manifold being one piece for the bassa head engine but that may have come later as my S4 and others I have seen have the 2 piece ones. Possibly later S4 or the S4R is one piece, but interchangable by the sounds of things anyway.