ratio411
Founding Member
Can't say I agree with any of this. There have been a jizzillion flow tests and dyno runs over the years that prove that there is very little performance difference between the 3 different styles of GT40-style upper intakes. Besides, if the upper was really the defining piece, guys like Tom Moss wouldn't find so much performance by porting the lowers.
It's a moot point though, because even ported, the lowers barely hang with the aftermarket intakes.
I don't doubt that you saw rpm gains from a box, not trying to dispute that. That's what boxes do. It's just a common misconception that the Explorer intake is somehow inferior to the other two.
I'll have to find the flow charts online to make everyone happy I guess. (Not dyno test, but flow charts.)
The Tubular upper is the best flowing over a broad range.
The stock 94-95 upper is the next best performer (suprise!)
Next is the 93 upper.
Then the Exploder was somewhere between the 93 and the stock HO upper.
If I find that chart, I'll post it.
Yes, Tmoss does get plenty out of the lower, however, I am quoting Tmoss from a conversation we had when I say the GT40 lower is a great piece. Granted he may have been talking more about it's potential than it's stock form, but that's what he said. The aftermarket lowers don't really beat the GT40 lower, it's the uppers that make the difference.