porting heads
Reply #2 –
My experience is that porting cast iron heads is tedious, noisey, messy and time consuming. Is it worth it?
Yes, without a doubt.
You should start by port matching the heads to the lower intake. A felpro 1255 gasket is one of the most popular gaskets to use. However if you are match porting the factory lower intake, a 1255 will only work with a few select factory castings. Check out tmossporting.com for the exact casting numbers. If you have to use another casting, you will just have to use the slightly smaller gasket.
Remember that you don't want to make the intake larger than the head opening. It is better to be slightly smaller on the opening of the intake into the head than vise versa. The two ports on the factory lower which need the most work are the #1 and #5. These can be opened up some to equal out. DIYporting.com shows this quite well along with porting of the e7's.
When porting the e7's the head should of course be port matched to the intake. The chambers can be unshrouded, the bowls blended, and the ports opened up some. Remember on the ports not to "hog" them out too much and on the bowls blend the contours but don't alter the shape too much.The bowl should actually neck down right before the seat. Summit sells some undercut valves for about $225.00 which might help flow when getting the valve job done. Beehive/conical springs would be another welcome addition. With the mods, you would have a nice set of e7 heads BUT, they would still be e7 heads and there is only so much you can do with them.
If you do decide to port them yourself. you will need an electric or air grinder with 6" carbide burs, 2"-3" burs as well cartridge rolls. Forget about using and electric drill. It is too heavy and bulky. Build a cardboard or wooden grinding compartent, wear safety glasses, hearing protection, and a dust mask. You won't believe how many metal shavings you'll make! An air regulator will help control the bit from dancing around and as long as you don't gouge the seat, you will be ok. That is also why you should follow up porting with a valve grind.
FWIW, if you are starting from scratch, you will be miles ahead if you just go out and buy a set of tfs or afr 165's. On the other hand if you like to make factory parts go fast....then....
... have at it!
Topic: porting heads (Read 893 times)
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