Going for big boost on a forged 5.3
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09-02-2009, 11:59 PM
#12
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Using your 3.779 bore and a OEM MLS .051 gasket and assuming the deck height to be about -.008 and 2.0 cc's for the piston head volume gives a compression of 10.397. A set of 243's will drop you down to 9.98 and 317's lower you to 9.25. I think the 243's will require a lot of Meth and reduced timing to run 15lbs. If your not going to run Meth, I think you would be better off running the 317's. With a 220 cam, I wouldn;t be surprised if a good tuner could make ,ore power with the 317's. That said, the 243's will be more responsive off boost.
This is a link to the Compression calculator I used if you wnat to play with it -
http://www.kb-silvolite.com/calc.php?action=comp
Rick
This is a link to the Compression calculator I used if you wnat to play with it -
http://www.kb-silvolite.com/calc.php?action=comp
Rick
09-03-2009, 12:12 PM
#15
I stuffed together a forged 5.3 with flattop pistons, 241 heads, GM MLS gaskets, arp studs and a LPE gt2-3 cam. @16 lbs boost this thing really sings. It gets regularly beaten like a drum and asks for more. Pump gas and no meth.
09-03-2009, 04:38 PM
#16
Look up Cometic and see what they can do for the thicker gaskets.
ARP head studs would be a must as well for reliabilitys sake.
As far as the heads are concerned, 317s will cause valve shrouding on that small of a bore. I'd personally do some 243s... Shoot for a compression ratio for a hair under 10:1
Could Wiseco put bigger valve reliefs or a dish in them maybe to drop some compression??
ARP head studs would be a must as well for reliabilitys sake.
As far as the heads are concerned, 317s will cause valve shrouding on that small of a bore. I'd personally do some 243s... Shoot for a compression ratio for a hair under 10:1
Could Wiseco put bigger valve reliefs or a dish in them maybe to drop some compression??
Using your 3.779 bore and a OEM MLS .051 gasket and assuming the deck height to be about -.008 and 2.0 cc's for the piston head volume gives a compression of 10.397. A set of 243's will drop you down to 9.98 and 317's lower you to 9.25. I think the 243's will require a lot of Meth and reduced timing to run 15lbs. If your not going to run Meth, I think you would be better off running the 317's. With a 220 cam, I wouldn;t be surprised if a good tuner could make ,ore power with the 317's. That said, the 243's will be more responsive off boost.
This is a link to the Compression calculator I used if you wnat to play with it -
http://www.kb-silvolite.com/calc.php?action=comp
Rick
This is a link to the Compression calculator I used if you wnat to play with it -
http://www.kb-silvolite.com/calc.php?action=comp
Rick
241 heads??? what are those
09-04-2009, 08:39 AM
#20
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2nd that. The 243's are so expensive because they flow so much better than the LS1 and LM7 heads. The 317's have the same ports and flow as the 243's but the big chamber turns most people off unless they are going boosted (as in your application). They are so cheap because there are a million sets around.
Cylinder Valve Lift in Inches
Head .200 .300 .350 .400 .450 .500 .550 .600
LS1 137 187 207 223 228 237 242 243
LS6 156 204 225 243 257 267 275 278
Go with the 317's.
Rick
Cylinder Valve Lift in Inches
Head .200 .300 .350 .400 .450 .500 .550 .600
LS1 137 187 207 223 228 237 242 243
LS6 156 204 225 243 257 267 275 278
Go with the 317's.
Rick