01 Banks header to a older 0631 head

Do I need an adapter plate if I change my 0331 head to a 0631 head? I have a Banks header for a 01. I thought you only needed an adapter plate if you are running a stock exhaust manifold on a 0331 head.

1993 Red XJ said:

Do I need an adapter plate if I change my 0331 head to a 0631 head? I have a Banks header for a 01. I thought you only needed an adapter plate if you are running a stock exhaust manifold on a 0331 head.

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Any 4.0 Banks header should work fine for all HO heads. No adaptor needed.
You will need to make up brackets for the coil rail since the 0631 head does not have the mounting bosses.
It's been done before so a search should come up with examples

A stock 2001 manifold does not correctly fit earlier heads.
The lower portion of the exhaust ports, on early heads, are bigger, the 2000-2001 manifold does not fully cover the early ports.
An adaptor is the wrong way to go as it will restrict exhaust flow, by covering part of the exhaust port.