I have tried searching for a difinitive answer to this, so I'm asking you enthusiasts... What is the difference (visually or flow performance) of the lightning 351-based GT40 tubular intake and the old-school FRPP tubular GT40 intake? I know the Lightning lower is a well engineered piece flowing 275cfm stock, but how do you know which intake you have? Any visual ques?
Difference between Lightning GT40 intake, and FRPP GT40?
- Thread starter rbonella
- Start date
Are you asking about the upper specifically, or the upper and lower? The lower is obviously 351-specific... I was under the assumption that the upper was the same piece as the FRPP 302 version.
The GT-40 uppers weren't side-specific. They can be flipped to face either way.
The GT-40 uppers weren't side-specific. They can be flipped to face either way.
Yeah, I figured they could be flipped, long story short...I have a 357 with a tubuler gt40 and I don't know if it's from FRPP or if the previous owner strapped a lightning upper and lower on it. I also do not know if there is a big difference bwtween the two uppers if any? Did a search and a few f150 forums claim the lightning upper is a little different to promote low end torque. Tmoss reported on a different thread that the lightning lower is a pretty good piece, and when ported can be great 300-325cfm. I was hoping someone could shed some light on this subject
Well the lowers are completely different. The 351 lower is wider than the 302 lower. It won't fit on a 302 at all. This is why it flows better...because it's a wider casting to the runners have more room to sweep and flow.
351 gt40 lower
302 gt 40 lower (narrower)
No idea if the uppers are the same. There are 3 versions of the gt40 upper...so the L prob got 1 of them.
The EGR spacer is different..due to the L having a driver's side TB.
351 gt40 lower
302 gt 40 lower (narrower)
No idea if the uppers are the same. There are 3 versions of the gt40 upper...so the L prob got 1 of them.
The EGR spacer is different..due to the L having a driver's side TB.
Tanus
New Member
got another queston about 351 lowers.
the 302 truck lower is similar to the holley systemax intake (rectangular ports). do they have a 351 lower with those same rectangular ports?
the 302 truck lower is similar to the holley systemax intake (rectangular ports). do they have a 351 lower with those same rectangular ports?
Thanks 5L5, from what I have been hearing, the 351 lower is not too shabby flow wise, is there another upper that would flow more than a GT40 upper and bolt to the 351 lower? Downs Ford used to make a breadbox upper intake...black with heat dissapation fins on top. I don't think they manufacture those uppers anymore, is that correct? This would be a great alternative to me having to buy a new upper and lower
Some say the Explorer upper manifold offers better flow distribution than the Cobra and GT40 tubular.
Short of the Downs box, not sure anything else uses the staggered port setup. A nice 351 lower gt40 manifold with a Explorer upper intake and 70mm TB and EGR would be how I would do an EFI 351.
Short of the Downs box, not sure anything else uses the staggered port setup. A nice 351 lower gt40 manifold with a Explorer upper intake and 70mm TB and EGR would be how I would do an EFI 351.
No, the 351 truck lower intake looks like the far right. No other upper will bolt to it.
As a comparison, the 302 truck lower is in the middle and does accept the holley/saleen upper.
302 HO to far left
I don't have the two in front of me, but that 302 lower looks identical to Holley's, and it accepts the Holley upper. I'm sure they're small variations between the two, but Holley developed an intake that Ford was already doing, or was it the other way around...Ford paid Holley for their design? Who knows...thinking about it too much i guess lol
Tanus
New Member
thats odd that the 302 truck lower would have better flow than the 351 lower, or at least it certainly appears to flow better. that sucks, Id love to have my systemax upper on a 351.
Yeah there's been discussion on this on the F150 boards. Doesn't make sense at all really why Ford used that intake manifold ont he 5.0 truck.
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