porting a tubular gt40 intake

dresmnkaos

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Jan 28, 2004
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i know the lower can be ported but can the upper be ported as well or are the walls too thin for that?

what gains would be had in porting a tubular gt40 intake upper and lower?

if both is possible what kind of work needs to be done to the intake to get the most flow outta it?
 
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From everything I've read you can't port the thin walls of the tubulargt-40 upper.

T Moss who visits here is the man you need to contact for all or any info about gains when you port a lower.
 
well the thing is i have an explorer intake, got it for like 40 bones, but i dont like the looks of the explorer upper. i was gonna utilize the lower and jus get a gt40 upper. i think the gt40 is gonna be on the border line of being enough for my motor. thats why the question cam about porting the gt40 upper.

i may jus go with the TF street and be done with it.
 
:scratch: So the lower can't be ported?

That seems to contradict what T Moss says is the reason I’m asking?

I do not not think so. I asked T Moss for a price to port my lower and he only offered to open my throttle body to 75mm.

Tue, 29 Jan 2008 05:21:15

Re: Porting GT40 upper intake, GT40 lower intake, and GT40p heads.

Yes, there is enough meat there to take it to 75mm - that is 2.5mm off the circle (2.5 on each side = 5mm overall). The front runners do not need to be straightened on a 351W lower. the lower does not need porting. To open the upper I charge $60 plus return shipping cost. Sorry, I do not port heads anymore, but Mike Shultz (aka Thumper) does a nice job- www.thumperoforangepark.com
Tom
 
the lower can be ported and the upper throttle body hole can be opened to 75mm if desires. The only thing you can't mess with is the tubes.

That's what I thought I read before.... but then when you read
Not much porting that you can do with a tubular GT40 i doubted what i read.
there will be no doubt about porting the tubular gt 40 next time thanks to Tmoss.
 
It's not entirely true that you can't port the upper, but you really can't do much with them. For the price of extrude honing them out, you'd be better off finding an intake that flows what you were hoping to accomplish with the port job.
 
what all do i have to do to the lower to get my motor to except the "gt40" lower. i read somn about drilling and tapping but cant find where i read what size tap to use and all that good stuff. do i have to do anything to the headers to run this intake?
 
dresmnkaos
i think your talking about a sensor that you needs to be drilled and tapped. if so then you need to tap it for a 3/8" NPT since all the sensors are tapped that size.