gt40 help? intake
- Thread starter bighack02
- Start date
Vinnietbird
Member
- Jun 2, 2005
- 584
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You can port it to match. No problems there. I have to question the effort involved. If you're on a crazy low budget....like I am, look around and find an Explorer intake. They can be found for around a hundred bucks, and are a great deal better than stock. The Explorer intake will flow as well as the Cobra and GT40.
Agreed. The explorer intakes can be found quite cheap and are essentially a gt40/cobra intake with a less good looking upper.
striker911
Member
I just put a exploder intake on mine and paid $40 at the junk yard. Man is that beast fast. Couldnt be more happy with it. 
Maryland Stang
Active Member
I wouldn't bother, sans an inspection, it's likely that your gasket matching would actually hurt horsepower.
Right now the ports on the intake are smaller than the ports on the heads. That means that there would still be a straight shot from the intake into the heads without the possibilty of a gasket getting in the way or a mismatch between the heads and the intake.
If you make the ports on the head and intake the same size and shape you have to make sure everything is lined up perfectly when you install everything. Since we know that parts are never milled or manufactured to exacting specifications the chances of 4 ports being misaligned using the gasket matched method are extremely high. You could even run into the possibility of all 8 ports being misaligned.
There is also the issue of killing the reversion even if you do somehow manage to get the ports lined up.
Google "Ed Curtis gasket matching" if you want to read what one of the leaders on 5.0 racing thinks about gasket matching.
Maryland Stang
Active Member
There is also the issues of the pushrod pinch and the dog legs on runners 1 and 5. Until you fix both of those issues I wouldn't even attempt to increase flow through the intake ports.
If you port the stock lower HO intake well, the intake will flow right at the same numbers as the GT40 head and the intake will work well for a street engine. Use a stock Felpro intake gasket (MS93334 I think) set that is very close to the size of the head ports and use it as a template on the lower - I have an illustrated instruction on how to port an HO lower in the Tech Doc section here:
EECTuning.org • Index page
EECTuning.org • Index page
This is all very unlikely if you use a template that is the same size as the head ports and you use the bolt holes and intake-to-block deck surface to align the template.
Id go with the Explorer intake. Only issue there is that your air temp sensor may or may not work. You can either drill the lower like everyone I know or you can drill the upper and flip the sensor. Either way it beats the crap out of an even ported stock lower. You still have to run the stock upper after all.
If you do decide to port the lower dont match the gasket. Leave the port slightly smaller. Every little bit of velocity helps.
If you do decide to port the lower dont match the gasket. Leave the port slightly smaller. Every little bit of velocity helps.
Maryland Stang
Active Member
If one insists upon using a gasket to port (you'd be surprised at how many times a day the tech line at Fel-Pro has to say they're gaskets, not porting templates) I'd do this.
Lightly glue the gaskets exactly where you want them on the head.
Then sit the intake down on the gasket and bring about 10 ft lbs of torque on the bolts.
Then drill a 1/8" hole in each corner of the intake right through the gasket. You only want to knick the head just barely but enough to make a hole in the gasket.
Then remove the intake and gaskets and place the gaskets on the intake and line them up with the holes in the manifold and gasket.
When you're done porting take the gaskets and place them back on the heads using the holes you drilled to put them back exactly where they came from.
Then set the intake back on and line it up with the holes in the gaskets.
I know of no other way to get the precision you need for this type of porting to not hurt horsepower.
I've seen that methodd posted elswhere before - there are other ways of doing it accurately that are not as involved as pinning the gasket. Consider that placement is controlled by the bolt holes, front to back and top to bottom.
Maryland Stang
Active Member
There's too much slop in the intake bolt holes to get it right consistantly. People have been complaining forever that the gasket slipped and blocked the ports. That's why I used a FelPro 1262S on my intake. The port openings are so big that even if the gasket slipped it still wouldn't cover the ports.
