i have a 1979 302 out of a mustang and i want to know how to go about grinding out the intake and exaust ports, how deep do i grind? what do i use to grind? do i just match it to the gaskets? any help appriciated, thanks
I wish I had some pictures to post, but I have had excellent results by using this method. First, Grind out the exhaust port AIR injection "bumps" "almost" completely. Don't grind it ALL out, just about 90% of it. Then, smooth the roof from the valve guide outward to where the bumps used to be, and shape it like a teardrop. Don't grind the floor of the port. Also, you can widen it all the way through...but don't get carried away, there's water in there. I don't remember which gasket I used to match the port opening, sorry. Don't make it any larger than you have to. You want the exhaust port to taper outward in shape from the valve pocket to the port, in other words, it should be larger at the port opening than at the valve. This allows for exhaust port scavenging. On the intake ports, I just blended the bowls behind the valves (leave the ridge directly under the valve seat untouched--there should be about a 1/32" ridge all the way around where the bowl was not opened up to the size of the valveseat). That ridge causes turbulence in the flow, which greatly helps atomization (and torque). Streamline the valve guide boss all the way around it, then use a sanding roll (60 grit) to finish the entire port. No excess widening/enlarging of the port is needed. This is about as good as you're going to get stock iron heads on a budget. If you want more power, save your $$$ and go aftermarket, but decent power can be made with stock heads. Don't go any larger than 1.94 intake valves..in fact, 1.90 or 1.84 valves work better, and use 1.60 exhaust valves. Good luck
What ever you do . DON'T grind on the "short " side of either the intake or the exhaust runner . It was mentioned in the above post too and was called the bottom or floor . Other than than it is too hard to describe where to grind in words . What kind of application are you using these heads for ? Clean up the heads a little ? mild street performance with a cam ? Bracket racing ?
Damn... Ok...I ported my heads and did some of the things you guys said not to do. First, I removed all the EGR bump. Second, I removed the ridge under the intake valve seat. I am sure I did some other stuff you said not to.... What am I in for. Did I hurt the head or just reduce power and torque. I will attach some pictures..... Glad these are only 77 302 heads!! I will probably run them unless you guys say not to. At least I didnt hit any water!! Jim
As near as I can tell from your pictures you didnt go too crazy I cant see floor or short side of the runner but it looks lik you only smoothed it out a little and didnt take out a bunch of material . Now you have to get the seats reground and then blend that in too . This is where you find out if you have a steady hand or not .
Good to hear Good to hear that I didnt hurt them to bad (from what you can see in the pictures). I mainly just smoothed out the short side, didnt remove much material at all. I did take out all the egr bump and that is what has me worried. Is there not much material there between it and the water jacket? Also, I did remove the lip around the intake seat...How badly will this affect performance? Thanks for your time and info. Greatly appreciated!! Jim
that area around the EGR bump is pretty thick. Also, I have had good results by removing the valve guide boss completely on the exhaust. doesn't hurt a thing.
Yea you can contour the bump right down to the floor so it looks like it was never there . I found that the valve doesnt last as long as the guide is about 25 to 35% shorter .
