# 69 GTO 455 swap



## Mark8117 (May 9, 2017)

Need some help, I am sure someone out here as this.

Picked up a 69, has a 455 w/eddy aluminum heads. Picked up some hooker super comps headers and it is REALLY tight. Looks like we need to notch the drivers side frame for the back tube to get clearance.

Before we start doing surgery, I’m wondering if the engine mounts are different for the 455 vs 400. This is my first GTO so I’m not sure.
Thinking whoever started this didn’t use the correct mount

Any help is appreciated


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## bigD (Jul 21, 2016)

A 400 & 455 should use the same mounts, in a '69 body.

Back in the old days, I used some Hooker round ports, on a 455 with RAIV heads. Used the same mounts as what came on the car. It was a '69 RA3 GTO. Never had any header to frame clearance problems, with 400 or 455 engines, and either D-port or round port heads. Used both Hedman & Hooker headers.

There are probably some guys around who can cut out a section of the tube and reshape it, for clearance. My engine guy has made lots of header tube changes. But, I suppose the possible changes would depend on the particular header and exactly what change is needed.


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