Can you replace the stock 2 valve heads on a GT with Cobra or Mach 1 4 valve heads and go with it or would you have to change anything else...or is that even possible?

 

it's definately possible considering they all have the same 4.6 block. It wouldn't be easy. I hear there are tons of parts you have to interchange, some say it's easier/cheaper to just buy a cobra engine and swap it out. This is all word of mouth BTW no personal experience.

 

Off the top of my head this is a partial list of what you would need: timing chain, timing cover, headers, valve covers, intake manifold, ECU, plug wires, plenum and TB, throttle cable. Those are just some of the big items. I've never done it but I'm sure there are plenty of little parts you would need too.

 

No. It would cost more than its worth. Try a search. You should find everything youre looking for. This topic is almost as extensivly covered as "what gears should I get."

Matt

 

no u dont need a new ecu - all you have to have is a wrecked cobra motor and swap out the parts - if you did the work yourself it should cost - 1000-1500 bucks

 

Its true... it would cost more then its worth... if you want 4v heads... just buy a used mach 1 motor.. there only like $2500.

 

Since the 4 valve likes to rev, you'd also want a forged crank and 8 bolt flywheel. It's possible but you're better off getting a used 4 valve motor.