porting and polishing

[Fastfun]

I am planning on porting and polishing the heads on the motor that I will be putting in my truck(94 LT1 aluminum head). I found this link on how to port and polish and I thought I would share with other board members. Has anybody attempted to port and polish their heads and did they have any problems and was it worth the effort.
Enjoy

http://www.sa-motorsports.com/diyport.shtm

[GenIIIShorty]

that's a sweet link!

[mocwon]

Yeah, I've done it on 351C 4V heads. Hell, I even polished the lifter valley to a mirror finish to help oil drain back more quickly. It's a lot of work and quite honestly, unless you're building a race engine time is well spent elsewhere.

[72CSTC5]

Mocwon, you do not think you will see that much more power by doing this? How much horsepower do you think it is worth?

[cornutz]

It is a lot of work, but if you are looking to gain those few horses here and there (ie: headers, intake manifold, etc...) it is worth it... probably in the range of 18 to 20 horsies easy... depends on valve job too...I like to think that it is just something you would want to do to make your motor flow better, I guess it depends on the $$ vs. time thing though too. How much is your time worth?

Just my .02

[clay68c10]

I did a basic gasket match and just hit the high spots and casting crusties in my 454. No real problems other than it makes a hell of a mess. I did it all at work so as not to piss off all the neighbors with the die grinder. If you really compare the ports to the gaskets, there can be a pretty big difference as far as the smoothness of the transition from intake to head. It doesn't seem like GM was all that precise with their port castings in the old days. Your engine is a lot newer and it probably is pretty well matched up.
I say go for the gasket match and just knock down the crusties. Any more than that is a waste on a street engine.
Be sure to get the cutting heads designed for aluminum, the steel ones will load up with the softer metal and are difficult to clean out.

[mocwon]

Originally Posted by clay68c10

I did a basic gasket match and just hit the high spots and casting crusties in my 454. No real problems other than it makes a hell of a mess. I did it all at work so as not to piss off all the neighbors with the die grinder. If you really compare the ports to the gaskets, there can be a pretty big difference as far as the smoothness of the transition from intake to head. It doesn't seem like GM was all that precise with their port castings in the old days. Your engine is a lot newer and it probably is pretty well matched up.
I say go for the gasket match and just knock down the crusties. Any more than that is a waste on a street engine.
Be sure to get the cutting heads designed for aluminum, the steel ones will load up with the softer metal and are difficult to clean out.

Port matching is worth the time and effort.

[mocwon]

Originally Posted by 72CSTC5

Mocwon, you do not think you will see that much more power by doing this? How much horsepower do you think it is worth?

Can't say without dyno runs before and after. But, if I had to guess, maybe 15HP.

[cdowns]

one thing to keep in mind is that if you get carried away with the grinding wheel you can end up with a very expensive door stop

[LUV2XCLR8]

Link, Mine was done by a Professional, not taking anything away
from you do it yourselfers, but Like DOWNS said, u can go 2 far w/ it

[Mad Dog]

I've been porting my junk and other people's junk for a few years......my best advice is to take it slow, keep it simple and prepare that it will take some time. Start with a grinding wheel untill you get going, a carbide bit will remove too much too quick for a novice.

I would gasket match the intake, smooth out the chamber, and smooth the runners. That is a great start. Only attempt the short side intake radius and the valve guides if you feel very confident, or need an expensive paper weight.

[stllookn]

Hey...nice link I will save that...thanks!

[Stroker]

I'm not an expert by any means but I have done a fair amount of reseach about cylinder head porting.The LT1 head is a very decent flowing head as it came from the factory and can be improved on significantly with proper porting.But, as already pointed out it can be turned to junk in a hurry also. There are a number of different cylinder head and port designs and they all require slightly different porting to get good results. The type of porting done on a 186 head that produced exellent results may actually cost you power on an LT1 head.

My advice would be to continue to look for information specific to the LT1 or Vortech heads before you go at them with a grinder. My understanding of these heads is that the runner and port design as well as the casting quality was very good from the factory. Mild porting usually does not produce the 15-20 HP that it does on the older and cruder castings. Usually more like 0 plus or minus 10HP. There may be another 10 HP or so to be gained by the proper valve job also.

If you get more aggressive then you better know what you doing and have a proven port design that you're reproducing.

This book is a good one to have read if you plan on doing any porting and has some information on the Vortech cylinder head which shares much of its design with the LT1.
http://www.amazon.com/exec/obidos/tg...97554?v=glance

Here are a few more links:

http://www.chevyhiperformance.com/techarticles/95518/
http://www.babcox.com/editorial/us/us110128.htm
http://www.ws6transam.org/ported.html
http://www.gmhightechperformance.com/tech/0504htp_lt1/
http://chevyhiperformance.com/techar...8_0507_vortec/
http://chevyhiperformance.com/techarticles/46364/

[69 Short Fleet]

Great links! Every small amount of horsepower adds up imo.