GT40 Intake - to port or not to port

[langod]

I've got a tubular GT40 upper and lower setup that I'll be putting on my stock 5.0. From a little reading, it sound like I can expect maybe 15hp from the swap alone. Lots of people get the lower intake ported -- but they all seem to be running various aftermarket heads. If I get the gt40 lower ported would it give me any significant gains on the stock heads, or is it not worth the cost unless I'm going to swap the heads?

 

[ImThatGuy]

If you plan on keeping the intake for future use, go ahead and get it ported. When ported the GT-40 intakes flow very well, ive seen them on a few 700hp cars myself.

 

[crazycarlo]

Are you doing the porting yourself or sending it to TMOSS? Like mentioned I would do it regardless. If you plan on doing it yourself get an explorer lower from the junkyard cheap to practice on. There are direction on the web. I plan on doing my explorer intake as well.

 

[351stang]

Port matching the lower intake to the head intake port is always a good idea. Don't touch the upper intake.

I'd also double check the value of intake before you modify it. There are cheaper/better cast upper intakes from a performance perspective, but the GT40 intake was expensive and on a few special addition (non-ford) like the SCCA Mustangs.

I gave one of the things away 10 years ago. :mj:

FYI: A 1" phenolic spacer between the upper and lower was worth about 5 HP. Not just from a heat limiter, but from a runner length benefit.

 

[Dig Race]

With stock heads just do a gasket match on the lower, that's all that's really going to help. That intake can already outflow your heads.

 

[langod]

Saw this got bumped. I ended up getting the GT40 heads from the same seller. It was too good a deal to pass up. They have about 2000 miles on them.
I'll probably do a mild cam -- something that gives me some useful low end power. I have the upgraded injectors too -- I think 24lb. The springs have a 550 lift, I'll probably do roller rockers too since it would be silly not to while it's all apart.

I'm figuring I can expect maybe 60-70 RWHP increase out of that set up. You all agree?

 

[Dig Race]

Maybe 270-280hp some guys can put down 300. Gasket match the lower to those heads, you will be amazed how much smaller the intake side is. I did mine to a 1250 gasket and it's a nice fit with the gt40 heads.

 

[Mike Morris]

I extrude honed my lower GT40 intake back in the day and port matched it. I gained a tenth and mph in same conditions. Car was bolt ons with 1.72 rockers and stock untouched heads. I would say do it.