Difference between 243 & 799 heads
The thinner head gaskets will give a minimal increase in compression and they are pretty pricey at around $100 a pair for the cometics...depending on machine shop charges usually it would be cheaper to mill heads 0.030 or 0.040" and you pick up substantial compression around like half a point or more..
While the benefits are minimal for either, a .040 gasket will increase compression around .3 and provide a better quench which is beneficial. Milling plus mls gaskets will probably be more expensive than cometics plus milling reduduces flow and can increase valve shrouding. I reccomend both, but fact is fact if its one or the other the thinner gasket is the better option.
An .030" mill isn't going to be enough to shroud the valves to the extent your talking, a stock head gasket is 0.050, so picking up 10 on the head gasket doesn't have near the benefit of compression increase of 3 times that with mill, I didn't think the milling was that much $$...
What would milling the heads cost about roughly? If it's $50 and MLS gaskets are around $50 it would be cheaper to go just the cometic gasket route which are anywhere from $85 to $103 depending on bore size.
Let me edit that, those prices for cometics are for 1 only!! So $85-$103 each. http://www.texas-speed.com/p-2258-co...3910-bore.aspx
Let me edit that, those prices for cometics are for 1 only!! So $85-$103 each. http://www.texas-speed.com/p-2258-co...3910-bore.aspx
Last edited by Roarin_8; Aug 22, 2013 at 09:40 AM.
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
Topdon ONE vs. Artidiag 800 BT2: Which is the Diagnostic Tablet For You?
Pouria Savadkouei
Gas Monkey Built a 6-Wheel Ferrari Testarossa With a Corvette LT4 Engine
Verdad Gallardo
7 Most Reliable High-Performance Engines GM Has Ever Built
Verdad Gallardo
Amazing '71 Camaro Restomod Is Modern Muscle Car Under the Skin
Verdad Gallardo
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Pouria Savadkouei
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Verdad Gallardo
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Pouria Savadkouei
Top 10 Most Powerful Chevy Trucks Ever Made!
Hennessey's New Supercharged Silverado ZR2 Has 700 HP
Verdad Gallardo
I think .035" quench is safe. Kind of leaves you with the .045" gasket, and they are spendy.
On 91, I'd concentrate on quench first, CR second.
Just my opinion.
ron
I don't mind spending money on gaskets. It is cheaper than chunking a piston and doing a rebuild due to detonation. I value your opinion for sure.
Even a small mill on the head would be a good idea to get the cometic to seal properly. But.. what about the block finish? Will I have to get that decked with a cometic? Or just get some copper spray?
Even a small mill on the head would be a good idea to get the cometic to seal properly. But.. what about the block finish? Will I have to get that decked with a cometic? Or just get some copper spray?
It looks like cometic offers thinner gaskets even... 0.027" 
http://www.jegs.com/i/Cometic-Gasket...ductId=2848860
Maybe a bit too much quench?
To the poster above, 0.030 total quench?
So since the pistons come out about 7 thou, can run the 0.036 gasket and be around 30 like you say...
http://www.jegs.com/i/Cometic-Gasket...ductId=2848860
Maybe a bit too much quench?
To the poster above, 0.030 total quench?
So since the pistons come out about 7 thou, can run the 0.036 gasket and be around 30 like you say...
Last edited by Apocolipse; Aug 23, 2013 at 04:04 PM.
