Originally posted by 91ls1+Aug 31 2003, 12:40 PM--><div class='quotetop'>QUOTE(91ls1 &#064; Aug 31 2003, 12:40 PM)</div>
Originally posted by Sleeper@Aug 30 2003, 08:03 PM
<!--QuoteBegin-farmtruc
@Aug 26 2003, 09:45 AM

No boring or altering the engine block or rotating assembly , EXCEPT CAM.

you must keep the stock heads on.

you guys are missing something here
It would cost less to replace cast iron heads on a 99-00 rather than buy a 01+ with aluminum heads, cast iron heads I would assume are out of the question. If your gonna do a swap why not do it right the first time. [/b]
BUT the 99-00 have a longer crank than the &#39;01+ blocks...meaning they only bolt up to a 4L80E.

The &#39;01 use a crank spacer to be used with a 4L80E trans...means a 4L60E bolts up easy, then the 4L80E needs the spacer.

A 99-00 is only a good core block to use. I&#39;d toss the heads and crank. Find a used LS1 crank (same stroke and shorter) and find some 4.85.3 heads for high compression or LS1 heads for decent compression