Is this a good block 5.7 LG SGI 14093638?

That is a 350 that was used from 1987 to 1995, It could be a 2 bolt or 4 bolt main and did not say for sure. It could also have a roller are flat tappet camshaft in it.

It does have a 1 piece rear main seal.

The only problem they had with them is the block cracking down in the lifter gallery.

Those blocks were thin and weak in that area. Not a good block for high performance useage are high RPMs. Hope I helped.