07NBSChevy

iTrader: (1)

I know Cometic has had a bad rep in the past with coolant leaking issues in the past. But I am wandering if Cometic has made any changes and/or is still having recent issues. If so, does anyone recommend a better head gasket? I do not want to have the block milled. I plan on milling the 243's .010" for a 10.5:1 SCR and 8.25:1 DCR and using a Cometic MLS 3.910" Bore .045" Compressed thickness gasket on my LMG 5.3 to achieve a .038" Quench/Squish. Just want to check with the forum before making the jump to Cometic.

I have looked into Fel-Pro MLS but they do need make a gasket in the right bore. Mr. Gasket only sells a 3.945" bore in .045"

64post

iTrader: (5)

Clean trued up surface(s) on the heads and block, proper torque and sequence and new headbolts, TTY or ARP with lube will avoid sealing issues, any thing less? Well there's a better chance it will fail. Bolt holes not holding coolant/oil will help you as well. Some people use Permatex.copper spray to help, not sure it's necessary.

mchicia1

iTrader: (5)

Never had one issue with cometic gaskets. I just did my lifters 2 months back, used a new cometic and stock gm bolts and zero issues.

07NBSChevy

iTrader: (1)

I will be using ARP head studs with the ARP Ultratorque assembly lube and thread sealer where needed, using acetone to clean the block and heads.

I just do not want to be in the situation were it leaks and I have to take the heads off again. I am debating just using the stock GM head gasket and keep the Quench are .045"

mchicia1

iTrader: (5)

You won't have problems if you clean the surface of the block and heads well. You don't have to go insane, I don't even scrape, I just use some brakcleen on a rag and rub real hard. Been using cometics for years with no problems, don't let the internet scare you.

The bolt holes is where I take my time.

07NBSChevy

iTrader: (1)

Thanks for the reply, I did get some ordered yesterday. I will make sure block is flat and clean.

Exidous

iTrader: (11)

Ever since I learned what a proper quench does for a motor I have used nothing but cometic. I have also never used the copper spray. Just normal surface cleanup with some scotchbrite and carb cleaner.

I used the .040" for a .033" quench. I measured all of my pistons for rock to make sure there wouldn't be any issues. The quench made a HUGE difference in tuning and knock resistance.

mchicia1

iTrader: (5)

Yep, great cheap mod if the heads are already off anyway. My car with milled heads and .040 leaps at any throttle.