I measured the head bolt spacing on LS1 heads as compared to our 194-292,& from cylinder to cylinder(front to back), there exact, bad news is they are about 1/2 inch off top of the block to the lower part of the block.

I think they (the LS1's) have the same bolt spacing as Small block Fords, & inline 300 six Fords.

12 port SDS EFI