5.3L...... which manifolds???

[Sicmaro]

Originally Posted by Hart_Rod

Here's some information on the factory manifolds that Shifty posted (pic included):

The set of ’98 Camaro/Firebird manifolds (top) worked best for us (PN 12567706 RH, 12559507 LH). Other possibilities include ’99-’03 Camaro/Firebird (second from top), ’99-’03 C/K Silverado (second from bottom), and ’97-’03 Corvette (bottom). These manifolds have 2 1/2-inch outlets that Cole was able to build a complete exhaust off of.

Ive got all 3 of the pictured ones except the top set (98 Camaro)