Gt 40 Heads.

Woodnut said:

ADVICE PLEASE I have a 66 mustang with 289 and i am wanting to put some gt40 heads on, which ones cobra or any other??? I am new to this site so your suggestions i would value. I will be using 4 bbl and weiand warrior intake and mild cam extractors. if i use the cobra 40 heads with 1.7 ratio will these work with hyd flat tappet cam. or should i use standard gt40 heads and add comp cams magnum roller rockers etc.

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You'll want to find a set from a '95-'96 Ford Explorer. Dimensionally, the Cobra GT40 and Explorer GT40 are the same heads. The GT40P's found on '97+ Explorers have a slightly smaller exhaust valve and spark plug angle, which can make fitting standard style headers a difficult challenge.

Whether or not they'll work will depend on how much cam you've got and what your piston to valve clearance is.