why exactly won't a 4.2L exaust manifold fit on 4.0l h.o.? - Pirate4x4.Com : 4x4 and Off-Road Forum

Taso Stambolis · 10-11-2003, 10:18 PM

? That question as always bugged me.

Robert · 10-12-2003, 01:33 AM

The 4.0L intake ports are higher up on the cylinder head than on the 4.2L. This is the major reason for thier better airflow and higher power potential. Because of this, the intake mounts up higher on the 4.0L head than on the 4.2L head.
Now if you look at how the intake and exhaust manifolds bolt up, they share several bolts. If the intake is sitting up higher, the shared bolts will miss one manifold completely, and will not fully clamp down the other manifold.

10-11-2003, 10:18 PM	#1 (permalink)
Taso Stambolis Registered User Join Date: Jul 2002 Member # 12878 Posts: 466	why exactly won't a 4.2L exaust manifold fit on 4.0L h.o.? ? That question as always bugged me. Last edited by Taso Stambolis; 10-11-2003 at 10:26 PM.

10-12-2003, 01:33 AM	#2 (permalink)
Robert Registered User Join Date: Jun 2000 Member # 1050 Location: West Sacramento, Kalleyforneeya Posts: 2,399	The 4.0L intake ports are higher up on the cylinder head than on the 4.2L. This is the major reason for thier better airflow and higher power potential. Because of this, the intake mounts up higher on the 4.0L head than on the 4.2L head. Now if you look at how the intake and exhaust manifolds bolt up, they share several bolts. If the intake is sitting up higher, the shared bolts will miss one manifold completely, and will not fully clamp down the other manifold. __________________ Ask me anything about a Cummins, I stayed at a Holiday Inn last night.

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