Posted by Troy Rudolph on December 13, 2001 at 16:19:01:
In Reply to: thanks Troy and Wietse, plus more ??'s posted by Adam Wilson on December 13, 2001 at 15:27:53:
My recollection is that the 3453cc block is the only one with siamesed bores. Wietse says that both the 3430cc and 3453cc have them.
I think the "hot ticket" is the '89-'93 535/635/735 engine. It make 209hp in stock form and 223hp with a Conforti chip. I would look for one of those complete with the injection system before I would start building something. Sayther Auto (512-442-1361) has a nice one just waiting for you.
If I were going to build something and pay for machine work, I'd probably get a '85-'88 block (they're cheap) and bore it out to 94mm.
As for free-revving, the 3.3L (3210cc actually) has the same stroke as the 3430cc so there's no difference there. Some people refer to the 3453cc engine as the "short stroke" 3.5. Granted the stroke is shorter, but only by 2mm or .0787 inches which is not enough to make any substantive difference. What the the 3453cc engine so good is the camshaft and compression ratio.