Hey guys I've got a buddy with and ls1 that has worn valve guides that are causing a little bit of oil consumption. He has this checked and confirmed by a well known local shop. With the abundance of cheap stock ls1 heads out there he is just going to get a set of stocker and put them on. The question he is curious about is there any power or advantages to having the heads milled a bit while they are off the car? He is not going to have any port/polish work but is curious about milling. He will eventually want to run a cam only car. So that is the question:

Is there any advantages from milling bone stock ls1 heads on a cam only/stock cam car?

Josh

 

the more you mill the more compression you build. compression is your friend unless you go fi.

 

What are some good specs to mill at and still run a decent lift cam...any setups right now that anyone else is running?

 

you do lose lift capability when you mill right?

 

Correct, by milling the heads you're brining the size of the combustion chamber down as well as brining the valves closer to the piston. ALWAYS check PTV clearance but you should be able to get away with a little bit of milling on a LS1 head. Compression = street car friendly as well as "free" horsepower as long as you can still run pump gas.

That's what i've always seen anyway.

William

 

My aftermarket ls6 heads were milled 60 thousands. I had to replace the pushrods with shorter units since the factory rockers are not adjustible.

 

What is typicall known as the maximum milling allowed to still run lets say a .620 max lift cam on intake or exhaust?

 

Not really sure it would depend on heads and valve events. I know of someone who milled a set of ls6 heads .015 and a thinner head gasket (by .015) for a total of .030 closer tolerance and it's ok with a .600 lift cam.

Whose doing this Josh?

William

 

You need to stop and think about the whole combo. More lift on stock heads may buy you very little.

Put together the right combo of cam, milling and compression for how and where you drive. It doesn't take very long to put it together and the results will be much better than a mismatched bunch of parts and specs.

 

with stock heads, you might mill the .15-.30 and stick a tr224 in.

 

It would be on my z28. What length prods did the guy with this setup run btw?

 

If the valve guides are gone is it possible the rings are weak also, ie you've already lost compression and the whole engine is tired?

What is the cost of a set of heads?

add milling?

What do you have?

Why not a salvage yard lower mile LS-1 engine? And while you have it apart add a new clutch. Now in my eyes, you have something

 

I went with 7.4 pushrods in my car. Seem to be working fine so far. Make sure to measure everything and double check before final assembly. I would find a set of used LS6 heads and start with those or 5.3 heads. As has been said if you want a decent sized cam without much head work you're gonna reach the limits of that ls1 head pretty fast. Might as well have work done to a stock casting while you're there. I did a clutch when i did mine also

Before I would take .030 off the heads i'd do what i did and take .015 and run a thinner gasket. If you did for whatever reason run into problems you could just get a stock gasket and make up a little more room. Also you'll get the same compression and quench with the thin gasket and mill as just milling but the valves will be a little more open.

There is alot of good info on this site, do some lurking and come up with a combo and research it so you have a battle plan.

Good luck and let me know if you need help when it goes down.

William

 

Car still made 170psi on a compression test done just 7,000 miles ago and runs consistent 12 second passes on street tires. I'm not at all worried about the motor and am very confident in my diagnosis.

 

How much milling could be done to still maintain my stock pushrods for now? I won't be running into a cam setup until late this year or early 08 so I am planning on setting this up on the stock cam/valve train. I will be running stock felpro gaskets as I have good experience with them. I found a set of 241 casting because like I said money is slow right now so I'm just setting it up for cam only while im on this shortblock.

Any advice?

 

Whats the typical price for milling as set of heads?
Doesn't the PTV clearence depend on the cam its self not the lift or i am i mistaken? Since it PTV comes in contact close to the overlap section not the max lift?

 

Also here is another question. How much better is each head going to flow stock vs. stock. I mean if I have a chance to get a cheap price on lightly used 806 casting vs. a little more expensive 241 casting is there any real gain to be had from the 241's while in stock form? I know 241's have slightly higher compression due to smaller combustion chambers. Also would a stock 5.3 head be totally worthless on the stock motor?

 

Milling will reduce the cam duration more so than the max lift... Definately worth milling while theyre off the car.

 

I would seriously just do the cam while you're there, it's MUCH easier. I mean just about everything you're going to want to change you're going to have to for the head swap. Spend the little extra or wait and do the cam at the same time.

William