WHat do these terms mean, and how can they improve hp

 

Improves airflow which leads to better power since more fuel can be more efficiently burnt.

Ben

 

I've already done ONE V-8 head of mine for my LT-1 for my 1967 Camaro RS/SS Convertible.
I really dread going back and doing this again.
I have 3 more heads to do (a pair for my 1974 Corvette engine, too!).
10 hours per head.
But I also know I'm being made to do it right.
BUt 10 hours per head.
My big problem, I got these heads for "free" and they are the best cast iron old tech GM Chevy heads made.
Gotta do it.

For you:
Increase incoming air flow
Increase ignition spark (not by just adding a "box" rebuild the distb!)
Increase exhaust flow.
If your engine runs fine, don't waste the effort.

 

All of this is done with a grinder; either an electric one (as made by Dremel or Craftsman or similar), or an air-powered one.

Porting = removing metal inside the ports in the head to enlarge the ports and to remove obstructions

Polishing = removing all roughness inside the ports so the air flows more smoothly (and therefore, flows faster)

Some guys say to only polish the exhaust ports, and leave the intake ports a bit "rough" to help the air mix with the fuel, but it's up to you.

Visit http://www.sa-motorsports.com/diyport.htm !! It shows you how to do it.

 

Look up gasket matching on the internet. Do it to your heads, thrittle body, plenum upper and lower, and exhaust manifolds. If you gasket match all those items you will look at a 10-20 HP gain. Now if you do it right and polish them real nice and port them slightly more you can see as much as 30 HP if you also shave 1/1000th off the heads deck..

 

would porting with a dremel rotary tool work? i dont think it will have enough torq to be productive...

 

So, yes. Torque isn't the main thing; speed is. Keep in mind what the Standard Abrasive website says- you DON'T want to push a stone faster than it's rated for! Stones can fly apart- wear eye protection! Let the stone cool down every once in a while, too. Now, If you were grinding with a 300 pound stone, you would need some torque. If you're using the correct size stones (tiny suckers), you'll be fine. Of course, the smaller the stone, the longer it takes to grind, but you'll be less apt to remove more metal than you should.

Oh; I should've mentioned that- If you hog out the ports too much, your motor will flow too much air for the fuel it uses. You'd need an adjustable fuel pressure regulator to compensate. It's best to just do a "minor" port job- clean up the ports, smooth out sharp edges, etc. Let the professionals do the major port work!

One more thing: You'll notice, inside the intake ports (larger valve), there is a raised "floor" inside the ports, that looks like a hump. Don't remove it!!! This was added by GM to enhance flow! It looks like a restriction, but oddly enough, it works!

 

Good tip Tomp !

 

Hey Tomp any pics of your car and the engine bay?

 

No "real" pics yet... maybe over spring break. I need to get a digital camera, then I don't have to develop anything, I can just put in the computer. But you can see my car's ***, if you go to that engine swap page of mine, http://www.geocities.com/tomp_3rdgen . Seems like everyone thought Geocities was a fast connection, so it'll probably be my "home" for my future f-body webpage. Of course, I'll pay the $10/month to get rid of the advertisements so you guys don't have to bother with 'em.

 

HA, I like that last shot of u two guys hitting drinks together after the job is done, must feel pretty good

 

Yeah, don't polish the intake side. I have learned that if you polish the intake side of the head that the fuel tends to 'puddle' on the polished side, which does not promote ideal combustion. You want to leave the intake side a little rough or 'dimpled'. Polishing the Exhaust side is OK, but not necessary. The air is moving so quickly and is so hot that it doesn't matter so much what the exhaust port surface is like. You might see like an extra 7-11 hp gain from polishing the exhaust side, and that is under ideal conditions, but for how much more work? And if you screw up the polishing (which is actually pretty easy to do), you've wasted a set of heads. Not good. Something to chew on a little...

By the way, if you have a local machine shop that builds race engines, just hang out there and ask questions, see if you can watch 'em do a little head work. Most guys are really willing to show you the ropes. After all, professional racing is a dying art, and they are looking for people to pass the torch to. Good luck, and have fun!

 

You are right about a dying art.
The art of more speed!
I chatted with an 18 year kid from local high school (Football guy).
He just got a 1965 6 Cylinder 3-speed Mustang.
It doesn't go very fast on the freeway.
I gave him some stuff to create a ram air inlet set up.
Have to pass the knowledge.
He told me that there are a few old rides (Old Mustangs/Camaro etc).
He was so proud not to be into ricers!