GT40 3 or 4 bar heads - Forums at Modded Mustangs
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post #1 of 8 Old May 29th, 2013, 08:57 AM Thread Starter
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GT40 3 or 4 bar heads

So I have 3 bar heads on my car. Didnt even know it till I looked. Look at my sn and you will understand. I was reading about gt40p's and all that good stuff. Till this day, I dont know the difference in a gt40p or 3 or 4 bars. Anyone can really break it down in plain language? Will I see a gain with 4 bar heads? or just keep what I have. Reason I ask is cause I have a complete motor and trans extra I was gonna rebuild instead of selling.
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post #2 of 8 Old May 29th, 2013, 09:16 AM
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3 bar heads are GT40 heads, while 4 bars are GT40P heads. Both are great heads when ported, but I can't offer any data on which is better than the other. I do know you'll have to buy a set of GT40P specific headers, if you go with the p's. The spark plug holes on those heads are perpendicular to the block, rather than at an angle, which is why stock and most aftermarket headers won't work with them.


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post #3 of 8 Old May 29th, 2013, 09:27 AM Thread Starter
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Yea I read that also about the headers.
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post #4 of 8 Old May 29th, 2013, 01:58 PM
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From what I've read. There might be a very very slight advantage to GT40p heads due to the spark bowl size/shape or some such.

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post #5 of 8 Old May 29th, 2013, 03:24 PM
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put it this way, the p's do not have enough of an advantage that its worth swapping them. even if you got them for free it wouldnt be worth it. if you want more power either get a power adder or start saving up for a better HCI.

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post #6 of 8 Old May 29th, 2013, 04:58 PM
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This is good reading
Five.Oh Info : The Ultimate Ford GT40 and GT40P Cylinder Head FAQ

Originally Posted by azure mach! View Post
That went from majestic speech to surprise buttsex really quickly
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post #7 of 8 Old May 29th, 2013, 06:32 PM
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FYI you can buy stainless steel headers for around 114 that works with all heads on ebay. They're actually really good quality. Not like procomp products.... lol
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post #8 of 8 Old May 31st, 2013, 02:44 PM
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Originally Posted by TBacon View Post
Great info! Thank you for the link!

Now a 48 year old bachelor with no common sense.... Occasionally racing his daily 12 second commuter up here in Utah...:
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