Hey Guys. Been a looong time!! Still living and "The Green Goblin" is still in my possesion. I am going to pull my 462 out this fall just to go through it. I was considering doing some porting on my iron heads but not sure on what h.p #`s I might see doing this. The gains might outweigh the costs. Any thoughts!! Later, Tony.
Unless you are REALLY attached to the heads OR have more time than money, aluminum heads are the way to go for bigger power. They will run more compression without detonation fears and loose 100lbs over the nose. Availability might be your biggest issue.
Availability is the issue though. Without aluminum heads you can order and get in a reasonable time frame more people will be wanting to port iron heads. I have thought about giving it a try on some I have, just to have a backup set.
When I had my heads off to change the head gaskets. I did some minor port work myself after the heads came back from the machine shop, gave myself 30min per port (going slow with a dremel so no massive amounts removed) to clean up the bowls and gasket match the ports to the intake. Don’t know how much power it made, but it couldn’t be worse than stock. Would I go all out and have them professionally done? Probably not, for that money I’d go aluminum, unless there was some class rules for some racing event.
Just use high flow undercut valves...clean the bowls and smooth the transition from the seat to the bowl takes minutes to do and provides the most gain
Thanks guys. Aluminum heads would be my 1st choice hands down, but availability and $$ are the issue. My heads had the bowls worked when the engine was built. I suppose I will inquire with the machine shop about this. I won`t be spending gobs of $$ for just a 10-20 h.p gain.
Aluminum heads are nice for all out, but you can get a moderate boost in performance porting your irons AND save thousands! I went thru the same scenario with the aluminum heads for the 350, I had ordered the bigger valves, level 2 porting, etc, etc, waited so long I had time to think it over ( over a year and a half) I’d have close to 5000.00 in my heads for a little power gain. I decided to buy another set of iron heads, have fun and port them myself, Stevem gave me a lot of good info. I saved a TON of cash!
Not to be mean, but porting with a Dremal tool is like mixing a wheel barrel full of concrete with a tooth pick. The good thing that I can state about the rework you did that way is that you likely did not do harm to the stock intake or exh flow numbers .
I can’t quantify anything yet about my porting rework, or the addition of half to 3/4 point more compression, BUT the engine feels more responsive, as in eager to pull, especially on the highway, and I’m sure the small bump in compression to near 12 to 1 would not have that type of effect. Per your recommendation of not hogging the ports/bowls out to keep velocity up seems to work!
Lol, I had an air powered die grinder as well, the difference in speed removing material wasn’t that bad. A big electric die grinder would be the best, but I just used what I had and had carbide burrs for both. The noise of the die grinder and air compressor (both very loud) made it not as pleasant to use, so I just quit using it after a while and was able to listen to music while working.
I have been waiting to post this until I had finished the iron heads I am posting about. Note that this is not a maxed out porting job for these particular heads, however I did take the intake ports from a stock size of about 153 CCs up to 175 or so CCs. In this photo is a typical 1 gal size freezer bag and it now has 3.5 lbs of cast iron grindings in it. 4 of the exh ports out of the 8 take a lot of grinding also, and to be fair some of this grit is from cutting the 16 guides for positive type valve seals and from reworking the oil drain back areas of the head, but then again a lot of the port work grindings went on the floor. This is just from the work bench top. I think this sheds some more light on my previous Dremel tool comment, no?
