tbirdscwd

Well, I pulled one of the stock heads off my stock motor the other day while starting to degree my cams....and I decided to mess with them a bit. I'm thinking I will do a little work to them and then when the time comes to pull my motor apart and put the CMS cams in, I will just swap these heads on at the same time.

The plan so far is to finish modifying the stock valves to gain a little clearance so I can take the heads in to the machine shop and shave a bit off the heads. The material taken off the heads should more than compensate for the small amount of material removed from the valves. I will most likely leave the chambers alone, but will do some minor portwork on the intake and exhaust runners. Nothing major, probably just port matching the intake to the gasket/manifold, cleaning up the whole runner and removing the bump in the roof that is under the lash adjuster bore.

Here is step 1 in the head process. Modding the intake valve. This is done to gain clearance on the intake side to allow for a better cam spec without notching your pistons. This is a good alternative for someone not wanting to tear apart the motor or don't feel comfortable notching the pistons while they are still in the motor. You can also do this in order to gain a little clearance and then shave a bit off the heads to gain a little compression. You have a couple options for gaining clearance on the intake side. You can cough up the cash for a set of aftermarket valves or you can modify your stock valves. I like doing stuff myself and since I am not going to increase the size of the valves, I figure that the stock valves aren't going to flow significantly less than an aftermarket one. You might want to just go for aftermarket if you don't have the right equipment, but you will also need a valve job for the new valves as well. Since the whole point of this is to do the work for as little money as possible.......modding the stock ones is what Imma doin.'

The preferred method is to use a lathe, because it is very fast and you can be incredibly accurate with the amount of material being removed. It can be done without using a lather, but I don't recommend it and I won't even go into how LOL

This is how the first intake valve came out.

Before


After


Now for a couple side by sides

mrtstang

Nice job man! Did you get a little worried about doing those cams on the stock heads.

tbirdscwd

It's kind of a long story. The cams don't scare me at all even at 108ICL. The initial tests I have done show .045" clearance, but I am still waiting on the adjustable lifter to make an honest zero lash measurement.

I have been floating around the idea of headwork or heads ever since I bought these cams. I don't have the money right now for the heads that I want.....but I do have a spare set of stock heads that have like 18K on them.....and I have a good amount of tools to play with. So, I'm gonna do some mild work on these heads, which will only cost me time and about $200, and throw them in with the cams.

The only reason I am taking the lip off the valves is so I can shave the heads down. Whatever I end up taking off the valves is what I will shave off the heads.....so I'm not really gaining any clearance on the piston to valve side of things LOL

mrtstang

Gotcha! I'll be interested to see how this turns out.

tbirdscwd

I'm trying to do as much stuff as possible myself that way I can do a little write up when it's all done. I know quite a few guys would be interested in doing some minor headwork and gain a handful of hp without just dropping $1000-2000 on a set of heads for someone else to do it.

The goal is to only have the machine shop do the valve job and the shaving.

mrtstang

Yeah, i might be one of those guys lol. I've seen some guys do this and actually loose power or not gain any, so i'll be watching this thread.

I hope this all works out where you gain similar power as professional p&p job.

tbirdscwd

I have seen both sides of the coin. I have seen guys hog the runners out and lose power, and I have seen guys do some minor cleaning up, and port matching and ended up picking up over 20hp. It's definitely one of things you need to be careful with. The work I am going to be doing is definitely not going to be on the risky side.

medrick

i paid $800 for low mileage ported/polished heads with aftermarket springs and valves that flow something like 40cfm over stock. shouldnt be paying 2000 unless you get trickflows.

mrtstang

Well, he is saying between $1000-$2000 probably to cover the most broad spectrum.

03greyGT

Looking good man...so do you have any plans do to a small piston notch? There was a writeup on another forum just recently that showed how a guy did it himself with an old valve and some sandpaper...seemed to be the way to go if your on a budget and dont want to tear the bottom end apart...