copper or MLS head gaskets

[1974dodgecharger]

for a Mild boost street blown car?  Looking at 15lbs max 20lbs of boost with 1471 blower.  What seals better and longer copper or MLS.

[John_Kunkel]

Is the block or head O ringed?

[Challenger340]

Depends...... no really it does.

If using an mls with 40ra or lower on the Aluminum Head mated to 50ra or lower Cast Iron Block/Honed using the Heads Studs/Spacers & T-Plate.... IMO, you will never have an issue.

If trying to just use the mls on "whatever" it may work for awhile....

Block & Heads O-ringed with receiver, silicon around the water jackets works fine.... but I've never used it on the street long term, so I can't comment over time ?

Just say'in here....
it's amazing how nobody ever seems to check what surface finishes are required for "best" results with Cometic mls, etc., etc. ?
Lotsa guys just bolt 'em on wheelbarrows/farm implements though and they seem to work    
all I know is we've seen them run damn near forever on 10.5" tire Ferds, prepped properly @ 20 psi ....

[1974dodgecharger]

Is the block or head O ringed?

SCE has copper head gaskets that dont require the O ring on block or heads anymore its called the ICS titan version head gaskets require a little silicone near water jackets to seal up from what I understand. 

[1974dodgecharger]

Depends...... no really it does.

If using an mls with 40ra or lower on the Aluminum Head mated to 50ra or lower Cast Iron Block/Honed using the Heads Studs/Spacers & T-Plate.... IMO, you will never have an issue.

If trying to just use the mls on "whatever" it may work for awhile....

Block & Heads O-ringed with receiver, silicon around the water jackets works fine.... but I've never used it on the street long term, so I can't comment over time ?

Just say'in here....
it's amazing how nobody ever seems to check what surface finishes are required for "best" results with Cometic mls, etc., etc. ?
Lotsa guys just bolt 'em on wheelbarrows/farm implements though and they seem to work    
all I know is we've seen them run damn near forever on 10.5" tire Ferds, prepped properly @ 20 psi ....

good info chalenger340 and YES I agree alot of backyard builders dont care about RA.  As a discussion i bring up with my friends they kinda get bored of it...My RA is finished to 70 average and from what I understand MLS wants a RA of 30 or so...The copper wants max RA80 so I could use copper off the bat who knows, but im curious whats best for street use and little track time here and there.  The most boost I plan to run is probably 15...im always pushing the limits on my engines then back off for daily use. 

Machine shop can do the O ring setup whats your opinion on them?  the head machinist kinda frowned up for daily beat up street use....for track car only he was more than happy to do it.

[alfaitalia]

https://www.enginelabs.com/engine-tech/gaskets-sealing/head-gasket-tech-pros-cons-mls-copper/

[Challenger340]

We've run KB Blocks and Stage V heads as described with the Cometics for street builds, no problems to report, albeit, at barely sufficient DCR in pushing the envelope for 91 Octane.  Many years on the Street, we freshened recently for the guys.

The biggest P.I.T.A. was getting the "correct" pattern Cometic built to "FIT" the KB/Stage V combo .....
which,
I can't comment on these new cast iron Blocks using the Stage V's exactly what number Cometic fits for clearance around the pushrods etc. ? I'm sure Tim will know though....


We'd run the O-Rings and Copper's on Blown Alky Hemi stuff, Top Alcohol etc. "back in the day", but again here....  I can't comment for street stuff as never done it ?
Just run whatever Tim suggests... he's far more current and doing them all the time !

We only do a few and strictly as time permits for Guys we've been building for for many years, and usually a struggle for us as "one-off's" LOL !