E7's Vs. gt-40's
Posting Guru
Joined: Mar 2002
Posts: 2,070
Likes: 2
From: Boise, Idaho
GT40p heads have the angled spark plugs. There are specific headers to fit these heads.
The GT40 heads have far better chambers than the E7 heads. In relative terms, the E7 heads are open chambered.
Powerheads are the ones who supply the information about the flow potential of those heads. I have heard from other people who have measured the Powerheads that their numbers are relatively high. Short answer, I'd take their information with a grain of salt.
The GT40 heads have far better chambers than the E7 heads. In relative terms, the E7 heads are open chambered.
Powerheads are the ones who supply the information about the flow potential of those heads. I have heard from other people who have measured the Powerheads that their numbers are relatively high. Short answer, I'd take their information with a grain of salt.
Freshman User
Joined: Dec 2008
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GT40p heads have the angled spark plugs. There are specific headers to fit these heads.
The GT40 heads have far better chambers than the E7 heads. In relative terms, the E7 heads are open chambered.
Powerheads are the ones who supply the information about the flow potential of those heads. I have heard from other people who have measured the Powerheads that their numbers are relatively high. Short answer, I'd take their information with a grain of salt.
The GT40 heads have far better chambers than the E7 heads. In relative terms, the E7 heads are open chambered.
Powerheads are the ones who supply the information about the flow potential of those heads. I have heard from other people who have measured the Powerheads that their numbers are relatively high. Short answer, I'd take their information with a grain of salt.
The GT40's Combustion chamber is 65cc and E7 & GT40p are 58cc, so in terms of open (which I never heard in a SBF, maybe BBC head) the GT40 will actually lower the compression, because of the larger CC.
I would refrain from the "I've heard" advice, this is the internet and proof is a click away, the OP and others deserve an unbiased opinion . I'm not a PWR head rep or supporter (just giving credit where credit is due) Furthermore, I don't think they would falsely advertise those numbers and have another site post them for an overall head comparison, without someone testing them and verifying #s.
When I was broke (still am
) and trying to make some power for my trusty ole 5.0 I would take the E7s out to the garage and grind/port away....a little something can be gained from almost nothing...E7s are dime a dozen, free in some cases, so getting a pair and playing is cost effective to me
Posting Guru
Joined: Mar 2002
Posts: 2,070
Likes: 2
From: Boise, Idaho
I would refrain from the "I've heard" advice, this is the internet and proof is a click away, the OP and others deserve an unbiased opinion . I'm not a PWR head rep or supporter (just giving credit where credit is due) Furthermore, I don't think they would falsely advertise those numbers and have another site post them for an overall head comparison, without someone testing them and verifying #s.
But if you want an example of how PowerHeads 'massages' their numbers, take a look at the spin they put on the data for their ported Australian 2v heads. They took a pair of Oz heads, installed bigger valves and did a flow test. The numbers were terrible, below what the stock valves in those heads would flow. Then they give the heads their porting job. They make claims about how much improvement they got before and after, but the improvement over the stock heads was marginal and certainly not worth the cost of the heads.
When you compare their published data to other published data for the same heads, you'll see that they are engaging in deceptive advertising.
To me, that certainly is false advertising.
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