Best cometic head gaskets?
02-06-2010, 12:00 PM
#1
On The Tree
Thread Starter
iTrader: (13)
Join Date: Sep 2009
Location: Virginia beach VA
Posts: 118
Likes: 0
Received 0 Likes
on
0 Posts
Best cometic head gaskets? What would be the best cometic head gasket to use for my boosted 5.3? I am using 317 heads on a 5.3 non-decked block: should I invest in the machine work for shaved heads and a decked block?
02-08-2010, 02:20 PM
#4
I'd go with a 5.3L MLS gasket with .051" thickness to give proper quench area if your running stock pistons with an undecked block.
Since your boosted I wouldn't mill the heads (unless they need trued up), but if you get the heads ported you PSI will drop, and at the same time make more power because of the increased flow
Since your boosted I wouldn't mill the heads (unless they need trued up), but if you get the heads ported you PSI will drop, and at the same time make more power because of the increased flow
02-08-2010, 02:29 PM
#5
I'd go with a 5.3L MLS gasket with .051" thickness to give proper quench area if your running stock pistons with an undecked block.
Since your boosted I wouldn't mill the heads (unless they need trued up), but if you get the heads ported you PSI will drop, and at the same time make more power because of the increased flow
Since your boosted I wouldn't mill the heads (unless they need trued up), but if you get the heads ported you PSI will drop, and at the same time make more power because of the increased flow
Also is engine going to be street driven? If so I would shoot for 9.5:1 compression so getting the heads shaved a little bit is probly not going to matter much.
02-09-2010, 04:25 PM
#6
On The Tree
Thread Starter
iTrader: (13)
Join Date: Sep 2009
Location: Virginia beach VA
Posts: 118
Likes: 0
Received 0 Likes
on
0 Posts
I'd go with a 5.3L MLS gasket with .051" thickness to give proper quench area if your running stock pistons with an undecked block.
Since your boosted I wouldn't mill the heads (unless they need trued up), but if you get the heads ported you PSI will drop, and at the same time make more power because of the increased flow
Since your boosted I wouldn't mill the heads (unless they need trued up), but if you get the heads ported you PSI will drop, and at the same time make more power because of the increased flow
A 5.3l gasket wont clear the 72cc combustion chamber in the 317 heads. You need to use a 6.0L gasket (.051 thick as well) or a cometic 4.030 bore. These are what I'm running on my ls1 with 317's http://www.texas-speed.com/shop/item...d=603&catid=36
Also is engine going to be street driven? If so I would shoot for 9.5:1 compression so getting the heads shaved a little bit is probly not going to matter much.
Also is engine going to be street driven? If so I would shoot for 9.5:1 compression so getting the heads shaved a little bit is probly not going to matter much.
The heads have roughly 80K on them. I am going to have them checked once I receive them. the engine will be street driven as well, using all stock internals and the heads will be left stock as well. I dont plan on decking the block either.
02-09-2010, 07:42 PM
#7
A 5.3l gasket wont clear the 72cc combustion chamber in the 317 heads. You need to use a 6.0L gasket (.051 thick as well) or a cometic 4.030 bore. These are what I'm running on my ls1 with 317's http://www.texas-speed.com/shop/item...d=603&catid=36
Also is engine going to be street driven? If so I would shoot for 9.5:1 compression so getting the heads shaved a little bit is probly not going to matter much.
Also is engine going to be street driven? If so I would shoot for 9.5:1 compression so getting the heads shaved a little bit is probly not going to matter much.
thanks for clearing up my mistake, didn't realize the clearance was that close on the valves
Trending Topics
02-14-2010, 12:29 AM
#12
These are the 2 options for the 317 heads.
GM MLS http://www.texas-speed.com/shop/item...d=880&catid=36
Cometic MLS http://www.texas-speed.com/shop/item...d=603&catid=36
GM MLS http://www.texas-speed.com/shop/item...d=880&catid=36
Cometic MLS http://www.texas-speed.com/shop/item...d=603&catid=36
02-26-2010, 09:52 AM
#13
On The Tree
Thread Starter
iTrader: (13)
Join Date: Sep 2009
Location: Virginia beach VA
Posts: 118
Likes: 0
Received 0 Likes
on
0 Posts
To bring this thread back I have a question.
Just to be clear so I don't mess anything up.
I need 4.030 mls gaskets to run my 317 heads on my 5.3: correct?
Just to be clear so I don't mess anything up.
I need 4.030 mls gaskets to run my 317 heads on my 5.3: correct?
02-26-2010, 10:42 AM
#14
These are the 2 options for the 317 heads.
GM MLS http://www.texas-speed.com/shop/item...d=880&catid=36
Cometic MLS http://www.texas-speed.com/shop/item...d=603&catid=36
GM MLS http://www.texas-speed.com/shop/item...d=880&catid=36
Cometic MLS http://www.texas-speed.com/shop/item...d=603&catid=36
04-04-2010, 10:34 PM
#15
TECH Apprentice
iTrader: (20)
Join Date: Jul 2009
Location: Liberal land
Posts: 390
Likes: 0
Received 0 Likes
on
0 Posts
I did a search and stumbled on this thread. I'm just curious....I am running this combo as well. Why do you need a 4.030 bore in the cometic version thats intended for a 6.0? If the engine is not bored, shouldn't you be ok with a standard bore and not a .030 over bore?
04-15-2010, 12:06 AM
#16
Teching In
iTrader: (7)
Join Date: Aug 2009
Location: Burt, MI
Posts: 30
Likes: 0
Received 0 Likes
on
0 Posts
Another question...? I've seen mls head haskets get coated with some spray on crap (not sure what it was called) before they were installed. Do you guys recommend this on a LQ-9 build?
04-15-2010, 08:02 AM
#17
I did a search and stumbled on this thread. I'm just curious....I am running this combo as well. Why do you need a 4.030 bore in the cometic version thats intended for a 6.0? If the engine is not bored, shouldn't you be ok with a standard bore and not a .030 over bore?
Copper spray because some guys feel cometics need this to help seal better. IIRC Cometic requires an RA of 50 on the sealing surfaces....
