steve

justin, from my experiance, if you have never touched a set of heads and are going to "play" around, expect that it might not work out right.

some people have touched up there own heads yes, and have decent reults. porting heads tho is an art.

try to spend some time in the bowl area. clean it up is all. i would limit my work to that area.

also, i dont know what you mean the stock gasket is crap? its an o ring.

steve frank

99 Black Bird T/A

iTrader: (4)

Justin,

If you want to do this, get a pair of junk LS1 heads to practice on first.

As for the cam selection. I'd say you really need to flow the heads to see where they stall and where they flow best at BEFORE selecting a cam. Match the cam to the heads do not try to match the heads to the cam.

I'd also do a search and read up as this topic has come up before.

Good Luck

SSable

iTrader: (9)

Hi all, I've been reading the posts related to home polishing jobs and I'm on the verge of starting my own job on a spare set of 2001 LS1 Stock heads. First, I have 02 SS that is too slow! (for me that is!) I have bought a Standard Abrasives Kit to start the job. Question 1, is the swirl ramp the *** next to the spark plug hole? That would make the most sense due to judging the flow from the intake valve. Question 2, regarding head and intake gaskets. I would like to retain stock gaskets for the heads, what would be the benefit of Fel-Pro's, getting mixed reviews in posts. Also, the intake gaskets from GM are a joke. Would Fel-Pro be a good replacement and provide a reasonable template for porting? Question 3, related to above. What would be the benefit to mill .030 off the head? Other than increasing C/R. Lastly, I'm going with a Comp 216/220 .525/.532 114 LSA Cam, Crane 1.8 rollers and moly pushrods with the recommended Crane Springs (stock valves). Does anyone have this config on a M6 and have any suggestions, tricks or watch outs! Any input would be outstanding.

Thanks, Justin
<img border="0" alt="[judgement]" title="" src="graemlins/gr_judge.gif" />

PAULJ99Z

If you have never had experience porting or using a flowbench I would caution against "just opening up the ports". Doing this will probably result in less flow and velocity than the stock port configuration. Buy a junked head, and get with someone who has experience or a flowbench and find out what works. As ageneral rule, you want the cros sectional area of the port to decrease smoothly up to about 3/8-1/2" before the valve seat. After this area, the valve seat is one of the most critical areas of the head, impacting low and mid lift flow. Get this part wrong, and you can end up with less power than a stock head.

If you test these heads, you will find the flow in stock form is very good from .100"-.300", but falls off after .400" in a LS1 port. Good luck,

Paul J.

SSable

iTrader: (9)

Wow great info! Thanks for the tips guy's. The heads I do have are off a LS1 2001. I got them cheap, so I'm regarding these as my testing set. Unless someone out there has a unrepairable LS1 head that they want to get rid of! Does anyone have a recommendation in the houston area for head work? I know MTI will do it, but you don't learn anything on a trade in.

Justin

Jantzer98SS

iTrader: (54)

Might as well give it a try. I know of one person on this board that has gone 10's with home-ported heads. <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" />

Since you've never done it before, here is what I recommend. Don't open the ports up, but clean up the casting. Grind the valve guides boses down and smooth them out. Widen the swirl ramp which is next to the intake guide boss. DO NOT remove material from the short sides of the port, you can blend them in but don't get wild. Just grind on the actual valve seat to get a smooth transition from the casting in the port to where the valve will actually sit. Most of your gain will be on the exaust side. Grind the valve seat to get a smooth transition into the exaust port. Remove the bumps in the exaust port floor and widen the ports. And atleast grind/smooth out the rocker boss in the intake ports, it's the bump you see in the intake port.

You don't need to remove alot of material, that's where most porters/novices make their mistake.

You can see some pics in my sig. They're my old port design, but gives you an idea.

DrkPhx

iTrader: (15)

Jantzer - Great info! I ported mine and have some questions if you don't mind.

1) Is cleaning the valve bowl the most critical part of porting?

2) I only cleaned(i.e. removed and smoothed the
flashing) the combustion chamber. I didn't
smooth the swirl ramp by the plug for fear of
killing swirl and velocity.

3) The heads were milled 1/1000th.

4) I just cleaned up the intake ports; nothing
fancy here.

5) Here's my main concern;I ported the
exhaust ports pretty good. I stopped right
before the short bend radius leading to the
valve. My fear is I did them too much.

6) The heads were glass beaded after I
polished them (I know). I tried to polish
the ports again, but couldn't get the
same results. Isn't polishing mostly used to
reduce carbon buildup and accumulation?

Any help/tips or suggestions would be greatly
appreciated.