The stock PI intake manifold uses two "one-piece" gasket assemblies, one for each bank as shown below:
Most aftermarket manifolds are made by Dorman (and are crap, often sold under other brand names--NAPA for instance sells it under their brand) and use separate formed gaskets retained by grooves moulded into the manifold flanges:
- 2003 GT, UPR X, FRPP 24lb/h, Magnaflow, PP 70mm TB & plenum, Delta Force tuned,
Steeda UDPs, Ralco flywheel, RAM HDX clutch, 3.73s, 262 rwHP/305 lb-ft.
New ride (7/1/2013) 1998 Mercedes SL500-5.0L 32V VVT 326/347 HP/tq