GT40 advice?

Go ahead and call me a glutton for punishment, but Ive decided to port a second set of iron heads. After months of waffling back and forth, Ive decided not to use the Windsor Jrs I ported earlier. I can only find one set of headers to fit their relocated spark plug in my 65 Comet, and Im not too crazy about how much they want, so Ive decided to go with a set of gt40's I picked up on the cheap. Ive also decided to take a more careful approach than I did before, so Ive been studying the diyporting.com page to see what needs work and what doesnt. My goal for these heads is not to hog them out for max flow with a big cam, but "maximize the stock port" so to speak to use them with a stock roller cam, 1.7 roller rockers, gt40 intake, 65mm TB, and shorty headers on a 306. Between the DIY site, my (possibly limited) common sense, and what people have said regarding the W Jrs I ported, I have a question. Fortunately I was able to get a good picture of the area in question. Is it a good idea and will it help to widen the floor as follows?

Also, what are peoples opinions of the diyporting.com site? I agree with most of what it says, though not all. In particular, Im not too crazy about the goofball exhaust port shown on the gtP heads, and his logic of losing flow by raising the exhaust port roof seems to go against everything Ive learned.

yeah ive ported a bunch of heads at home over the years- i dont agree one bit about his roof theory. he is moving a velocity tube up and down as if moving the header primary up and down and what he is finding is the air is exiting upward not straight. there is alot of gains to be had in the exhaust port, you need to focus in the roof around the guide and gasket match it. you can use a hair dryer and feel with your hand the direcion of the airflow, you want to move the airflow so it comes out as straight as possible not upward, as far as the short turn on your intake port i wouldwork the whole thing more, even in the middle but i think youdo want the port to change to round from square at the valve. over the years i did alot of research on head porting and found alot of porters have their own flavor and oppinions, i always took everything into consideration and threw my own flavor on it. ive always picked up at the track, even on mod motors, chevy motors( my bro has 68camaro and i have a sbc in my boat) but ive made many e7tes and some c60e 289 heads rock and roll. ive also ported rpm heads too

I like the diy site because it compares the evolution of the windsor heads so well, regardless of what was done to either. It helps to show what the Ford engineers were doing to improve flow, and I think shows that they did a good job of it. Granted the gt40 or p head is not a big performer, but its arguably the pinnacle of engineering when it comes to production Ford windsor style heads.

After looking at the bend in question, Ive decided it would not be beneficial to square it off. I ground the entire port because it had what looked like chunky carbon buildup on it, but it was actually just rough casting and parting lines. I did open up around the pushrod bulge, but I think this will be basically a cleanup in the bowl area, trimming of the valve guide boss, and valve job operation on the intake. As for the exhaust, Ill do a more conventional port job on it. If I get these flow tested, and I doubt I will, Im hoping for about 205/150 cfm. Am I out of line to think that simple bowl work and a 3 angle valve job can do that on the intake?

I'd square that baby off- you just need to change to a square valve and a square piston and you'll be set!
Seriously, I'm no expert by any means, but what you want is a smooth transition from the round to the square, and I preffer to try to round the square more than square the round (if that makes any sense).
As far as the short turn radius, again, I like to work the middle just a fuzz more than the edges, effectively rounding that area to more closely match the valve. In other words, I don't do as much where the pen is pointing as the middle, but I do try to straighten and smooth the area on the side of the port below the pen.
One aside, don't get too greedy or agressive on the short turn radius, bad things can happen.

Originally Posted by doug351

just need to change to a square valve and a square piston and you'll be set!

I bought a bike from a guy that had an engine like that...