Here is a list of suppliers that people modifying the 4200 have used. Many of the parts for the 4200 interchange with the I4/I5 (2800/2900 & 3500/3700).
Rear sump oil pan
oil pan Bell housing flange adapters - convert the atlas bell pattern to SBC/BBC etc.
adapter plate High strength engine sleeves
Darton
Cam shafts - Bullet Racing - will supply cams including the cores. << NEW Feb 22/19
Connecting rods
K1
The owner of the '69 Camaro that appeared in Aug 2011 Car Craft had K1 connecting rods make up minimum order of 4340 rods. He bought one set for his current build, and the last time I asked there were 7 sets still at K1. The cost of the rods is reasonable compared to Crower.
Crower
Crower made the rods for several projects including: Black Opel
Pistons
Ross
J&E
Racetec << make a longer skirt piston more suited for street use.
Valve train
Jessel
Bates Engineering in So Cal has:
1mm OS intake/exhaust valves for the 2900/3700 head
high tension valve springs / retainers / keeper
1 mm OS valve seats - specifically made for boosted app's
investment cast roller followers
Adjustable cam sprockets
Billet main cap girdles Pohill racing innovations London Ontario Canada
Main cap locating dowels: emtechmotorsports
Cylinder head reinforcement rods: Route 66 engine builders
Head and Main cap studs: ARP (require machining)
Bates Engineering: has no machine head studs
Supplemental oil feed fittings - these bypass the internal oil passage restrictions and feed oil from the load side of the oil filter directly to the main/rod bearings: emtech motorsports
High capacity injectors, Modified GM engine EFI harnesses, PCM reflash to remove security and tunes: lime-swap
4200 injection EFI services Another source for big Atlas Valves - they need to be custom ordered but available.
Products - supertechperformance.com
Stainless intakes and inconel exhaust.
Rod's:
http://www.molnartechnologies.com/ http://pauter.com/shop/rods/gm/gm-vortec-4-2l-l6-rods/SFI balancers: BHJ Products Inc
Camshafts - it you make and provide 8620 billet blanks then comp, & crower can make custom cams. Not cheap this is a $1500+ hit.
Archived information
https://groups.yahoo.com/neo/groups/inli...hiveSearch=true 
