Front clip pull - construction of dolly

When I determined that the engine needed a rebuild the GMC was already up on 6 of my 12 ton jackstands with the suspension, fuel system and brake lines already out. Therefore I could not do the usual "roll it out on it's own wheels" method. So I built a dolly to roll the front clip (subframe) out. It consists of a 4X4 wood perimeter on 6 casters with perforated angle steel supports for the connection to the frame. Why that method? I had the 4X4's on hand, the local steel yard had the angle for scrap price and the casters were on sale.