Cutting/porting upper intake

Topic: Cutting/porting upper intake (Read 4613 times) previous topic - next topic

Cutting/porting upper intake

November 28, 2004, 04:15:15 AM

I have a couple of extra intakes, and I want to try my hand at porting one. I've seen people cut them towards the back, and I was wondering how it was done. Plasma cutter? chop saw? hack saw? I have access to a plasma cutter and welder at work. any ideas?

Re: Cutting/porting upper intake

Reply #1 – November 28, 2004, 09:59:35 AM

intake for what year, what engine, and if it 5.0 the stock intake?

if yes don't waste your time..

i understand that it would be cool to be able to say you did it but guys only did that stuff in the 80's and in the early 90's because there was'nt any other intakes avilable back then..untill the cobra and the GT40 was available.. you could port that intake as much as you want and it still would'nt flow as good as a stock cobra or GT40.. and these days theres tons of intakes available for a reasonable price..
i got my GT40 intake back about 4years ago used for $275.00
and their are tons of under $500.00 new infact you can get a typhoon"edelbrock copy" for under $300.00 check it out http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&rd=1&item=7937613681&category=36474

theres allways deals out there for 5.0 intakes..

Nick

Re: Cutting/porting upper intake

Reply #2 – November 28, 2004, 11:26:54 AM

So what if he wants the experience doing it..?

Re: Cutting/porting upper intake

Reply #3 – November 28, 2004, 11:31:28 AM

He's right about the upper. Not a lot of power to be had there.... Where it IS hidden is in the lower. The lower portion of the intake is the bottleneck in this system. Port matching the runners on the head side to match with your heads and cleaning up the the runners further up the line is where most of the work is done. I've read that doing just this to the lower and NOTHING to the upper results in a Manifold that flows approximately 90% as much as the Cobra Manifold. Also you have with this setup a manifold that responds very well off idle to about 5500 RPM.

Re: Cutting/porting upper intake

Reply #4 – November 28, 2004, 09:05:38 PM

I cut mine with band saw

Re: Cutting/porting upper intake

Reply #5 – November 29, 2004, 05:30:13 AM

I wanted to do it because I don't have $500 to spend on anything, much less an intake. porting is free :D

I was planning on working the lower as well, I've seen an article on how to do that and what ones are really bad (front if i remember right) and what aren't (middle ones are almost straight).

Re: Cutting/porting upper intake

Reply #6 – November 29, 2004, 06:25:48 PM

I dont think that it could be all that hard to fab one... But I'll bet it is more trouble then its worth

Re: Cutting/porting upper intake

Reply #7 – November 29, 2004, 11:38:11 PM

Paul has it right...there's not much need to port the stock upper as contrary to what others think...it actually flows quite well and has good port to port balance. The lower is another story...particularily cylinder #5. If you're going to port, concentrate on the lower.

Re: Cutting/porting upper intake

Reply #8 – November 29, 2004, 11:48:36 PM

But what if he wants to port the upper as well?

What if he wants the porting practice, even if it's not THE solution for horsepower?

You guys sometimes bend over backwards talking people out of stuff.. like trying to talk everyone into a stick shift and a 302 and whatever, and heaven forbid anyone have an automatic or a V6 or what not. How about a little more help for those of us who like to experiment, or try a low-buck method now and again, or whatever? I can't speak for zpyro here, but if I wanted to drive a setup the same as everyone else, I'd own a Mustang, not two T-birds.

Sorry to sound like I'm taking you to task over this.. but it does seem to be a common thing around here. I have some interest in this topic because I'm considering getting some experience with porting/gasket matching. Even if it doesn't yield much in the way of horsepower, experience is always a valuable thing.

BTW, I understand that you're probably trying to save him what you consider an unnecessary effort. I can appreciate that sort of sentiment. However, it's not always right. If I had a couple extra 302 uppers to mess around with, I'd probably have asked the same question he did.

Re: Cutting/porting upper intake

Reply #9 – November 30, 2004, 12:38:30 AM

I never said not to port it.....just pointed out it's not really necessary. He'll learn more practicing on a lower anyway. All I do around here is offer advice based on my experience and let people make up their own minds.....I don't bend over backwards trying to talk people out of stuff because frankly in my experience it's a waste of my time because more often than not a lot of people asking advice on this and that already have their mind made up anyway before they even ask a question and are more or less asking to get a response from someone who agrees with their choice....thus making them feel like they are on the right path....even though they may not be.

Re: Cutting/porting upper intake

Reply #10 – November 30, 2004, 12:47:58 AM

True that many here have their minds already made up.. but to be honest, this (cutting the intake apart to port the entire upper) isn't something I'd have even thought about prior to this thread, but when I first saw it I gave it a little consideration. I was hoping that the responses in this thread might've been a little more helpful about the topic itself, not so discouraging. I have shaky hands and not a lot of confidence in them, so when it comes to the thought of porting work, I'm hesitant. If I could get a ton of porting experience.. uppers, lowers, junk heads, whatever.. I'd perhaps get past that. So he happens to have a few extra uppers laying around.. if I did, I'd probably use those for the experience.. even if it wasn't hugely productive from the performance standpoint. It would help on the confidence end of things. Again, I can't speak for zpyro's motivations, just how I see things.

And I was speaking more generally on the bend-over-backwards thing.. not targetting you specifically.. although you happened to be the one I responded to.

Re: Cutting/porting upper intake

Reply #11 – November 30, 2004, 01:04:08 AM

id cut the intake just to see what it looks like inside :p

Re: Cutting/porting upper intake

Reply #12 – November 30, 2004, 01:10:01 AM

Quote from: Manson

id cut the intake just to see what it looks like inside :p

I think I know what the inside of mine looks like.. black and shiny. :(

Re: Cutting/porting upper intake

Reply #13 – November 30, 2004, 01:21:01 AM

k, i cut it with a bandsaw at work. first I cut behind the two little plug thingies that are on the bottom of the intake (one is plugged, the other has a fitting and tube in it), but then realized that it was too far back, I wouldn't have enough room to get the grinder in there. so I cut it again, this time in front of the plugs. I started working the walls of the runners, making the leading edges sharp, so maybe it would cut down on any resistance/turbulance the rounded edges would cause. then I worked a little on removing the sludge and black inside of it, and making the runners a little bigger.

I also worked on the lower intake some. one of the ports (probably #5, I didn't notice which one it was, one of the end ones) which is all curvy I worked on the most, trying to take down the insides of the turns to make it a little straighter, but I could only get so far into it before the shaft of the burr I was using would start rubbing on the edge of the port.

I also worked on one of the heads, getting the valve guide bosses worked down. I'll try to get pics of all of the stuff I worked on.

Re: Cutting/porting upper intake

Reply #14 – November 30, 2004, 02:34:09 AM

pics time!! yay!!
k, here's the upper with the back chopped off

closer look

here's the particularly bad one on the lower

I'm sure it could use some more work, eh?

another bad one

now for the heads! these are all of the bowls

I know, not much consistency, but oh well