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Discussion Starter #1
Ok, just bought a ford 3.73 gear, and everything to install it, never
done one, ought to be fun!! I also got a great deal on a gt40 intake, fender cai and 70mm maf. I am going to rebuild my block back to stock, use the stock cam, 1.7 rollers, and my p/p e7's and the stock injectors. Ok now for the ?'s. Does this need a 70mm tb, or will a 65mm be plenty? Would it b worth porting the lower on the gt40? Oh, and what ya think, rwhp?? It does have under drive pulleys, and I am going to smog and a/c delete it while it's out!! Thx in advance for the help!!
 

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I'd say you're good to go with what you have.
Dave
 

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Ok, just bought a ford 3.73 gear, and everything to install it, never
done one, ought to be fun!! I also got a great deal on a gt40 intake, fender cai and 70mm maf. I am going to rebuild my block back to stock, use the stock cam, 1.7 rollers, and my p/p e7's and the stock injectors. Ok now for the ?'s. Does this need a 70mm tb, or will a 65mm be plenty? Would it b worth porting the lower on the gt40? Oh, and what ya think, rwhp?? It does have under drive pulleys, and I am going to smog and a/c delete it while it's out!! Thx in advance for the help!!
Which GT40 intake did you get?

A 70mm TB will be good if you plan on more mods down the road, but for now a 65mm will be plenty. I don't know how much HP gain you'll get, maybe around 15 with the new TB? But it will definitely be a noticeable change.
Porting the lower is definitely a good idea, I've heard that the lower is the weak spot on the GT40 intakes.

Check out my GT40 intake thread, My GT40 Intake Update!! - Ford Mustang Forums, it might give you a lot of answers... :bigthumbsup
 

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Discussion Starter #4
I dont plan on any future mods, unless I do a complete motor and none of this stuff will make it to that.

I know that the gt40 lower is the weak spot, just wanted to know if porting would do any good in this config.
 

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I dont plan on any future mods, unless I do a complete motor and none of this stuff will make it to that.

I know that the gt40 lower is the weak spot, just wanted to know if porting would do any good in this config.
A 65mm TB will be plenty for you.

The E7 intake ports aren't all that big, so I doubt you'd see much improvement by porting the lower intake on the stock heads...
 

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Discussion Starter #6
the heads have been ported.
 

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The E7 intake ports aren't all that big, so I doubt you'd see much improvement by porting the lower intake on the stock heads...
The idea of porting the lower intake is to equalize flow between all the runners. An unported GT40 intake has a 10% cfm difference between the best flowing runner (no.8) and the worst (nos. 1 & 5). The stock GT lower intake is even worse.
I'd say he'd have about 260-265rwhp with his planned mods. The 70mm TB would be fine and he's goog to go..
 

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The idea of porting the lower intake is to equalize flow between all the runners. An unported GT40 intake has a 10% cfm difference between the best flowing runner (no.8) and the worst (nos. 1 & 5). The stock GT lower intake is even worse.
I'd say he'd have about 260-265rwhp with his planned mods. The 70mm TB would be fine and he's goog to go..
I would guess more around 250ish RWHP... But it should run real well.
 

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Go with a 65mm throttle body, and the GT40 will work fine with those heads. It'll have good throttle response and be a good, mild driver.
 
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