After some extensive thought, I decided to hand port my existing 289 cast iron cylinder heads. Before someone reminds me that any aluminum head on the market, including the cheapest, will probably out flow even the best ported factory iron 289 head I'll explain my rationale. Quite simply, I don't intend to put much money into this existing engine. Hopefully by this time next year I'll have a fully prepped 347 stroker with a Weber induction, so I took the opportunity to do some cheap mods to my existing engine to run around this year. I bought a slightly used Holley 600cfm and Wieand Streetfighter intake on Craigslist, both for $150. I plan on installing a mild cam and lifters from Howards and have already purchased JBA's Tri-Y headers, which brings me to the desire to port my existing heads. I also looked forward to learning something new and if a little bit of power comes from it so much the better.
I read as much as I could regarding the subject and made particular reference to Glazier Nolan's Mustang Barn article which stated to spend the most time on the ceiling of the exhaust port. So that is where I began. I first needed to buy a tool to remove the valves. I got the Lisle spring remover from Amazon for $30. It's a great little tool. Simply put the handle over the valve, hit it with a hammer, and a magnet in the handle captures the keepers and retainer. Pretty slick. I picked up 2 TEMO carbide burrs (7" 3/8" ball end cylinder and a 3" 3/8 acorn) for $15 and $12 respectively. I grabbed a sandpaper roll kit from HF for $6 and went home Friday night to begin my weekend of grinding and sanding.
I began by removing the thermactor bump. This little bump extends into the port approximately 3/8 inches and really blocks the port. I began using the carbide burrs in my die grinder but the speed at which the material was removed was a bit intimidating and i felt I didn't have much control. I transferred the bit to a regular drill and it worked great. Not too slow and I could really control it well. After removing the bumps I went back and used my header gasket to draw a line were the manifold would lie. I tried to go approximately 1/16" inside the perimeter of the gasket to ensure a proper seal and avoid creation of a step between the two. I used a medium sharpie marker for the task and the line it drew was a perfect width. The port floor only needed a slight grinding as GN directions said but a considerable amount of material and flashing was removed from the sides and ceiling of the port. This took the most time. You"ll want to use the small tip of the acorn burr to get into the port corners and then work the flat sections. This way the corners stay tight. Go a little in the corners and then a little on the flat sections. Keep alternating to avoid grinding grooves which are hard to work out. The drill allowed a really low speed and I had enough control that the final grinding was just a feather's touch to smooth the lines. They aren't perfect but they're okay for me and my first time doing this. I will say if you have a spare set of heads to practice because my last port was much better than the first initially until I went back and cleaned it up.
I finished by grinding the valve guide down a bit as explained in GN's directions. Just go a bit and keep "rolling" the 7" burr into the valve area to make a smooth radius. It would be hard to really mess this up though because the port ceiling is there for a guide. You're just aiming to remove the little 1/8 inch bump from the valve guide. I finished by sanding everything with 80 grit sandpaper and then 120 grit.
I think they came out pretty good. The way Ford cast these heads I'm sure anything you do to them will be an improvement. Hopefully I'll feel the difference but if not I've gained a valuable experience and it only cost me less than $60 and some hobby time.
I read as much as I could regarding the subject and made particular reference to Glazier Nolan's Mustang Barn article which stated to spend the most time on the ceiling of the exhaust port. So that is where I began. I first needed to buy a tool to remove the valves. I got the Lisle spring remover from Amazon for $30. It's a great little tool. Simply put the handle over the valve, hit it with a hammer, and a magnet in the handle captures the keepers and retainer. Pretty slick. I picked up 2 TEMO carbide burrs (7" 3/8" ball end cylinder and a 3" 3/8 acorn) for $15 and $12 respectively. I grabbed a sandpaper roll kit from HF for $6 and went home Friday night to begin my weekend of grinding and sanding.
I began by removing the thermactor bump. This little bump extends into the port approximately 3/8 inches and really blocks the port. I began using the carbide burrs in my die grinder but the speed at which the material was removed was a bit intimidating and i felt I didn't have much control. I transferred the bit to a regular drill and it worked great. Not too slow and I could really control it well. After removing the bumps I went back and used my header gasket to draw a line were the manifold would lie. I tried to go approximately 1/16" inside the perimeter of the gasket to ensure a proper seal and avoid creation of a step between the two. I used a medium sharpie marker for the task and the line it drew was a perfect width. The port floor only needed a slight grinding as GN directions said but a considerable amount of material and flashing was removed from the sides and ceiling of the port. This took the most time. You"ll want to use the small tip of the acorn burr to get into the port corners and then work the flat sections. This way the corners stay tight. Go a little in the corners and then a little on the flat sections. Keep alternating to avoid grinding grooves which are hard to work out. The drill allowed a really low speed and I had enough control that the final grinding was just a feather's touch to smooth the lines. They aren't perfect but they're okay for me and my first time doing this. I will say if you have a spare set of heads to practice because my last port was much better than the first initially until I went back and cleaned it up.
I finished by grinding the valve guide down a bit as explained in GN's directions. Just go a bit and keep "rolling" the 7" burr into the valve area to make a smooth radius. It would be hard to really mess this up though because the port ceiling is there for a guide. You're just aiming to remove the little 1/8 inch bump from the valve guide. I finished by sanding everything with 80 grit sandpaper and then 120 grit.
I think they came out pretty good. The way Ford cast these heads I'm sure anything you do to them will be an improvement. Hopefully I'll feel the difference but if not I've gained a valuable experience and it only cost me less than $60 and some hobby time.