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</o:shapelayout></xml><![endif]--></head><body lang=EN-GB link=blue vlink=purple><div class=WordSection1><p class=MsoNormal>Team.<o:p></o:p></p><p class=MsoNormal>I have both an AH100 and an A90 engine sat side by side on my garage floor. It is known that the AH100 was developed to take advantage of the A90 Atlantic mechanicals and therefore I assumed that the A90 and AH100 engines were essentially the same.<o:p></o:p></p><p class=MsoNormal>When externally comparing these two engines there is a minor difference between them that surprises me. The AH100 distributor mounting base on the block has bolt holes tapped into bosses each side of the distributor hole. The A90 has a single boss and a single tapped hole.<o:p></o:p></p><p class=MsoNormal>This indicates to me that the AH100 engine had its own block casting at the very least, and perhaps other variations too.<o:p></o:p></p><p class=MsoNormal>Could someone advise if there any other significant differences between the AH100 and A90 engines?<o:p></o:p></p><p class=MsoNormal>Many thanks.<o:p></o:p></p><p class=MsoNormal>AlanB<o:p></o:p></p></div></body></html>