Head swap? 2005 Aviator to 1998 Mark LSC


El Presidente
Staff member
Paid Member
It seems like it might create some unanticipated backpressure and start wearing seals. That's just hypothetical.. Another option I'm considering is just adapting the cobra 96-98 intake manifold right into the C-heads. Any opinions?
Hypothetical is correct. I've researched this enough to tell you any gains on gasket matching is minimal at best. Nothing you would ever see off a dyno and I seriously doubt any concern with 'wearing seals'.

The best exhaust manifold option for full performance would be long tube headers, but it would require a significant amount of custom work.

As for the 96-98 intake manifold adapted to the C-heads, there are better options you could consider. There are several intake manifolds for the C-heads available you could utilize, both OEM and aftermarket. Your better bet would be a 99-01 Cobra intake for the C-heads..