So Ive ran into some oil leaks and found out I had a busted rear main seal. So $200 in repairs later I find out I also have blown gaskets on both heads and am leaking from there as well. This came as a surprise and its gonna cost me another $650 to get the heads taken off and gaskets replaced. My mechanic says he's
going to take them to a machine shop to make sure the heads are TRUE. So Im thinking, since the heads are already off, why not have the machine shop do a little porting and polishing. Would this be a good idea since this is probably the only time I'll have the heads removed? How much extra do you guys think it would cost if I asked the machine shop to do some somewhat mild porting and polishing? Any advice would be appreciated on prices and ideas about porting and polishing as well as how much Im paying for these repairs.

 

Screw having the mechanic do anything to them other than remove and re-install

Mill them .030 and put personally buy some head gaskets yourself. Get the felpros, impala SS thickness. Also do a 3 way valve job on the heads, that should be about 300 total (valve job and mill). Should bump your compression to the 11:1 range (maybe a tad lower), and give you some ponies with the valve job.

 

Sounds good to me. Too bad I dont know of any good machine shops around here to do it for me. Guess Id better start asking around now. Atljar, do you think I'll be able to notice much of a difference. Im sure I'll notice it much more with a cam. I was planning on the LT4 hotcam kit, would that be a good combo with the port job you described? Oh ya, I almost forgot. I was asking the mechanic about putting in a higher stall converter, shift kit, and tranny cooler since his prices seem reasonable and he told me not to do it. Says hes seen to many cars like mine tear up there rear end and u-joints by going that route. Well Im thinking, Ive seen to many members on this board go that route and not have a problem. The mechanics I go to always seem to have a different opinion than what I read on the board. I tend to rely on personal experience that I read from all you guys though.

 

Actually the forementioned isnt really any porting or polising. Its a process that will unshroud the valves to allow more air to flow through them (correct me if i am wrong engine masters, im not sure on the exactness of the process).

Between that and the compression, you should feel the gains, nothing earth shaking, but they will be there. If you want to go all out on a port and polish, you will spend big bucks (1000-2000 on work) but will have more power to show.

 

Take your valves out, buy a dremel tool, standard abrasives kit, and begin to port.

Don't worry about it. I was worried to death about porting my heads, but there's nothing scarry about it.

If you pay a machine shop to do your heads, go ahead and grab your ankles, cause you're about to get a new **** job also.

It takes time, but port match to the gaskets, and port behind the valve seats, make a smooth continous flow (use smoke if needed), take out all casting marks that were left behind, and you'll be in business.

Don't forget the 3 angle valve job. (machine shop)

Also, I milled mine .020 and got the felpro .039 compressed thickness gasket, and my compression is better than 11.1.

Just have fun and do it yourself, and you can't be dissapointed.

D Moss

 

If you're going to do it again and again, go for it yourself. If you're going to do it once, pay someone to do it. A dremel and some stones? You likely wont do enough to matter & would have been better off spending that $ on a halfway decent valvejob.

Unless you have the $ to do things right.. quality parts etc., I'd mill them as little as is needed, run an impala gasket, have a decent 3angle valvejob done, and save $ til it's time for something serious.

 

Mill them .030? hell no. Mill only as much to make them flat. The extra compression you gain from .030 vs fgetting them flat is going to have little effect on power, and only give you more headaches to worry about. Pushrod length, milling the heads in the future, etc.

 

.030 was fine on my buddies car with stock pushrod length, we checked with an push rod checker too. The increased compression is good for some ponies, and IMO will have more than a "little effect". Milling the heads in the future does become a concern, but he said hes only doing it once.

 

No, you will not notice .030 vs enough to get them flat. the small increase in compression wont be noticable. I dont even know what percentage of power you gain per point of compression, i think its like 5% or so.

Only doing it once? What happens when something goes wrong and the heads must be pulled?

IMO, and i believe in the opinion of most engine builders around, only mill them enough to make them flat.

 

Im gonna see what the machine shop he wants to take them to will do for me. Im thinking the 3 angle valve job, impy gaskets, and milling enough to make flat. How much would a typical machine shop charge just for that? I would venture out on my own and give it a try but I dont have the extra funds for the needed tools and dont even have a garage to work in. If I do serious work on the heads, it will be way down the road when this becomes a leisure vehicle and not a daily driver anymore. Hope all goes well and maybe get a few horsies out of it. Thanks.

 

Hmmm
Sound to me that your problem was the Lt1 intake gasket leak.
Whats the odds that the raer main seal and both head gaskets are leaking oil on the rear end of the engine?

 

Thats a possibility but my mechanic said they were leaking towards the front of the heads on each side.

 

I missed in the first post the .030 vs getting them flat, i read it as him not noticing the difference at all.

I have always heard 3-4% per point of compression. So gotta figure thats an easy 10hp bump over where he was.

Anyways, you are a seem to be a firm believer in just getting the heads fixed, i am trying to pull more power our of them for the same amount of money. You would error on the safe side of things, and i always like to push the envelope a little. To each his own, cheers.

 

Everyone likes hp. However you are looking in the wrong place for it.

300hp, 3-4% is 9-12. You are not gonna gain a whole point of compression by milling. So you are gaining under 10hp. Not worth it for potential problems, and possibility of not being able to mill the heads many more times in the future.

Simply put, compression is not a great place to pick up power, you wont notice the small increase.

 

port and polish yourself, 3 angle valve job by machine shop, milled by machine shop, and get the machine shop to stack your springs for @ .575 lift, that way when you go to get your new cam package, you won't run into spring coil bind.

I did this to mine and had less than $300 all together in a mean set of heads.

Thanks

D Moss