Hello, I am planning on doing several things at once over the next couple weeks and have a few questions. I didn't have the money for the heads I want so I am going to mill mine when swap the cam. I went with a .040 cometic so I could hopefully reuse it this spring when I get a good set of heads. I am going to mill my 853 castings .025-.030 to boost compression, but I am worried about fitment issues milling that much. Depending on how the valve seats look, I may be getting them reground and putting in new valves if necessary. I realize I may have to flycut by milling this much with a thin gasket, but I am hoping to sink the valves in the head a little when we grind the seats. While the heads are in the shop I planned on swapping the cams and intalling an LS6 valley cover, LS2 timing chain, stock LS6 oil pump and ARP rod bolts since I will have plenty of time. Now for the questions.

1. Any problem reusing cometics? I've done a search and heard both ways.

2. What kind of fitment issues will I be looking at by sinking the head a total of .042? I ordered 7.35 pushrods to compensate the valvetrain.

3. Is regrinding the stock valve seats and using the stock valves going to work for 6 mo. or so? In the last 4 years I have put less than 10k on ALL of my vehicles total. (my wifes van is the family mobile, I live 8 blocks from work.)

4. Should I sell the LS6 oil pump and buy a ported one for twice the price. Stock ones are CHEAP and I think it will be fine, but I may run an oil cooler in the future if I can.

5. Is changing the rod bolts in the middle of all this a bad idea? I thought I would have plenty of time and I thought dropping the pan would make not pinching the O-ring easier.

6. Anything you see I'm missing or should do while I'm in there? I'm in no big hurry to get all this done and would love to get as much done as possible. I thought about new lifters, but I won't really be revving til I get the new heads on next year.

Thanks for the help guys.

 

1. I also hear yes and no split decision. I dont really like the idea, unless theyre super clean.
2. 7.375 would have been a better fit, but you should be ok with 7.35. Maybe a tad noisier.
3. Shouldnt be an issue
4. IMO, you can port your own, shim if you want, Its not that big a difference.
5. You can, but its gonna be a big job.
6. Sounds like a good start.

 

If you sink the seat .042, and grind another .010 or so off the valve, then you will have to add at least that to shimming the springs. Also be sure to check your swipe pattern and I would double check your pushrod length as well.