V8 cylinder heads

KAC

Active member
Aug 10, 2020
29
7
Virginia
Are the cylinder heads the same for all Rover V8 motors (3.9, 4.0 & 4.2) Cux & GEM? How about the 4.0 & 4.6 with secondary air, are they the same as the earlier motors also?
Thank you, Karl
 

Tugela

Well-known member
May 21, 2007
4,754
562
Seattle
Someone correct me if I’m wrong but doesn’t an SAI head have holes that would need to be plugged? Also weren’t some heads 10 and some 14 bolt? I’m curious myself.
My RRCs (3.9 RV8, 1990, 1993) had fewer head bolts than my 1998 Disco (4.0 RV8). I don't remember the exact number, but I'm fairly certain they were different.
 

StangGT5

Well-known member
Feb 4, 2019
295
130
Atlanta, GA
I am pretty sure the 3.9 and 4.2 have 14 bolts. I know everything after has 10. You can use the heads interchangably, though you'd have to block the SAI ports on SAI heads.

A sure sign the headgaskets have been replaced on RRCs is if they are missing the lower exterior bolts. Shops usually use the newer black headgaskets, which only have provisions for 10 bolts. The extra bolts supposedly "side-loaded" the head to some degree anyway.
 

StangGT5

Well-known member
Feb 4, 2019
295
130
Atlanta, GA
no, only the early ones. Even my old 89 had 10-bolt heads, though they may have been swapped in.
I am pretty sure all the pre-serpentine V8s had 14 bolt heads. One of my 92s, purchased from the original owner's estate, certainly has 14 bolt heads.

That doesn't really matter for interchangeability though.
 

pdxrovermech

Well-known member
Jul 3, 2009
1,807
57
Portland, OR
I am pretty sure all the pre-serpentine V8s had 14 bolt heads. One of my 92s, purchased from the original owner's estate, certainly has 14 bolt heads.

That doesn't really matter for interchangeability though.
this is correct, but early 14 bolt heads are also slightly thicker and need to be machined down more if you're going to use the composite head gaskets.