на вортеке и колено другое, и поршни, и распред... и всё-всё-всё остальное. И как оказалось, по крайней мере неожиданно для меня, и 4л60е от вортека отличается от тбишной.
Интересно, а что конкретно получается из тби с вортековскими головами
The Vortec 5700 L31 (Vin code 8th digit "R") is a V8 truck engine. Displacement is 5.7 L. It is the last production Generation I small-block from Chevrolet. The cylinder heads feature combustion chambers and intake ports very similar to those of the LT1 V8, but without the reverse-flow cooling.
As such, the L31 head is compatible with all older small-blocks, and is a very popular upgrade. It offers the performance of more expensive heads, at a much lower cost. It does, however, require a specific intake manifold (A 5.7L, 350 CI L31, Vortec engine has eight bolts attaching the intake manifold or four per head, as opposed to the "traditional" six bolts per head; twelve in total found on older Chevrolet small blocks).