I am 2 exhaust ports into a basic porting on my heads, when i was told not to grind down those huge bumps in the exhaust ports. Obviously i would like to be told i didnt just f-up a perfectly good set of heads. Can these be ground down? Do they serve an important purpose? I hope i can continue grinding instead of trashing these heads.
thanks

 

Who told you that and why did they say you shouldn't do it? I've never done a 460 but a lot of guys here have and they all say that it's the best thing you can do for making them breathe better. I did a set of 351C heads for my 400 and the first thing to go was the bumps.

 

i agree with bill, the only thing you need to be careful with is not going too deep and hitting a bolt hole or a water jacket. when i did my d3ve heads, i completely ground off the humps, rounded off the sharp flat valve guide area (the technical term for it has left my mind), and slightly enlarged the exhaust ports overall. i cant say how much it helped because it was the first time putting the engine in and running it, but i can say that it runs hard and that i havnt had any problems with it.

 

Those humps were used in later model (71-up) heads to inject air into the exhaust flow, decreasing the smog output.
Worked on a pair of '74 heads (my engine), and JUST by grinding out those humps gained a good 28 horse on the dyno.
Since, I have sqeezed another 11 horse out of those heads, nearly 40 over stock, just by working the exhaust ports.. it DOES make a difference!
Beware, water jackets are your biggest weakness in that head. dont cut too deep past the hump, or you WILL run into a jacket.
Also, along the ends of the heads, make sure the air injection holes (running through the block into the smog humps) are plugged, or you will leak exhaust out of the ends of the block.
Good luck!

J/.c

1965 Ford Galaxie 500 (okay, so not quite a truck)
460/C6 transplant @ 389hp/491 lb.ft.
14.29@103.8, 13-14 mpg heheheheheh

 

It was not a mechanic or machinist that told me that. Just some guy. But wanted to be sure it was ok. Good to know i can continue porting. 28 extra HP, very good to know. I plan to plug the holes in the exhaust ports with a screw of some kind and then grind it smooth.
Thanks again for the help, now if you will excuse me i have some griding to do!