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LS6 BIG BLOCK CHEVY  
gkurth85
New User | Posts: 22 | Joined: 08/08
Posted: 09/07/08
06:51 PM

im running a stock style ls6 piston. they are sealed power L2349f60. im running a set of chevy 049 heads with 2.19 1.88 valves. with 1.7 roller rockers. i have a 620" solid roller cam right now i was wondering if anyone could tell about about how big of a cam i can run in this motor? with the same set up i have right now. im looking to get upwards of .700" is that possible with these pistons without having to take them out and have them dished?  


1967 el camino
468 bbc
12 bolt

 
GibTG
Moderator | Posts: 1360 | Joined: 10/03
Posted: 09/08/08
01:09 PM

.700" may be pushing it, but you will have to check the clearance. Flycutting is possible, use a lot of grease, tape, bags, etcetera and you could keep metal out of the engine.

Making sure your valve springs and the rest of your valvetrain are up to par is also very important.  


 
JW454
Enthusiast | Posts: 297 | Joined: 07/08
Posted: 09/08/08
02:01 PM

454 zero decked, .020 cut from 049 heads, 2.19-1.88 valves, Speed Pro 2465 pistons with .215 dome height, .039 head gasket only had .030 clearance piston to intake on overlap with .598-.615 cam. Had to fly cut in. reliefs .050. In my case, the exhaust (oddly enough) had .150 clearance. Also had to cut valve guides down.  


 
chaseturbo
New User | Posts: 34 | Joined: 09/08
Posted: 09/08/08
04:41 PM

After making a huge mistake on someones big block chevy, I always measure the valve/piston clearance without the head gasket. Clay the pistons like you normally would but do no put the head gasket on. It will allow a little. .020 .040 extra clearance for valve float. It would have saved that motor I built  


 
gkurth85
New User | Posts: 22 | Joined: 08/08
Posted: 09/08/08
06:02 PM

454ci LS6 Closed Chamber Head Piston, .060'' Overbore
Piston Dia.: 4.310''
Piston Top: 29.4cc Dome
Pressed Pin
Comp Ratio: 11.89:1 w/100.9cc Head, 10.01:1 w/119cc Head
Ring Grooves: 5/64'', 5/64'', 3/16''

my 049 heads are 118 cc chambers.
im curious if anyone has built a combo like this in the past and what kind of numbers did the motor make?  


1967 el camino
468 bbc
12 bolt

 
GibTG
Moderator | Posts: 1360 | Joined: 10/03
Posted: 09/08/08
06:30 PM

Those 049 heads will likely have 120-122cc chambers, not a 118.  


 
gkurth85
New User | Posts: 22 | Joined: 08/08
Posted: 09/08/08
07:03 PM

originally they were 122cc chambers but they have milled down to 188cc chambers  


1967 el camino
468 bbc
12 bolt

 
gkurth85
New User | Posts: 22 | Joined: 08/08
Posted: 09/08/08
07:04 PM

sry i meant 118  


1967 el camino
468 bbc
12 bolt

 
JW454
Enthusiast | Posts: 297 | Joined: 07/08
Posted: 09/09/08
01:04 PM

I have one I finished a few months ago. It sounds pretty nuts. Cant wait to get it in my 1980 Camaro over the winter. You can check it out in my threads "new 454 engine build". The best way to check that piston to valve clearance is with light springs, and unless your confident your machinist ground all the seats the same depth, you better check them all.  


 
gkurth85
New User | Posts: 22 | Joined: 08/08
Posted: 09/10/08
05:09 PM

im still stuck with the fact that im not to sure on what cam to run? well how big of a cam i am able to go  


1967 el camino
468 bbc
12 bolt

 
JW454
Enthusiast | Posts: 297 | Joined: 07/08
Posted: 09/12/08
03:18 AM

Why dont you pull the valve springs off the # 1 cylinder, and see what you presently have for clearance during overlap. Needs .080 in.- .100 ex.  


 
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