I don't have access to the specific firing order of LSx. I'll look into it. It may or may not be similar to the little Fords, but it is COMPLETELY unlike any of GM's other engines over the years. The valve "spacing' and "layout" are similar to the Ford, but "opposite". That is, where an exhaust valve is on "front" on one side and in the "rear" on the other, the LSx has the intake on the same side as the Ford does exhaust. (I-E-I-E-I-E-I-E for one, E-I-E-I-E-I-E-I for the other, if installed on the same "side") Of interest, the Ford "W" deck plate bolts right to LSx...
Strangely enough, the comparison was made in the article TOHCan referenced for the 4-7 swap information. It's near the end of the first paragraph on the second page. The little fords and the Gen III LSx have identical firing "patterns." (Using the word "order" will mess up most of the folks who forgot that Ford didn't number their cylinders correctly.)
