Should I go with my 5.7's or my 5.3's?
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Should I go with my 5.7's or my 5.3's?
I've got the stock 5.7L heads on my car now and I bought a 5.3L truck engine that burned oil, for $300, took the heads off of it, and sold the shortblock. So, I've got me a set of 5.7 and 5.3L heads, both of which are stock. I plan on running the G5X-3 cam, LT's and True duals. I also planned on just taking the one or the other set to a local shop and having them ported and larger valves dropped in. But which should I have the work done too? I have all the rockerarms and components for the 5.7s, but nothing for the 5.3's. Should I just sell the 5.3's and go with my stockers? Thanks.
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5.3'ls so u get an increase in compression w/out the millin of the heads that could produce p/v problems....the 5.3's...flow w/ported and have bigger valves as good as any 5.7.
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ok, cool. another question. I don't want to have to spend money for new Rockers, cause they're too damn expensive, so will my stock 5.7L rockers, work with the 5.3's?
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Originally Posted by AustinL911
ok, cool. another question. I don't want to have to spend money for new Rockers, cause they're too damn expensive, so will my stock 5.7L rockers, work with the 5.3's?
compression = horsepower
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Originally Posted by 770boy
compression = horsepower
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Originally Posted by JoSeY
5.3'ls so u get an increase in compression w/out the millin of the heads that could produce p/v problems....the 5.3's...flow w/ported and have bigger valves as good as any 5.7.
Most 5.3 heads I've seen don't even flow 300 CFM.
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Originally Posted by KingCrapBox
Most people I talk to say that 5.7 heads will out flow 5.3 heads pretty easily. I would think that milled 5.7 heads would be the best bet, because you would get the CFM numbers and the bumped compression.
Most 5.3 heads I've seen don't even flow 300 CFM.
Most 5.3 heads I've seen don't even flow 300 CFM.
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Originally Posted by JoSeY
they are the same casting....u will just need a port job on the 5.3l's....many NA 5.3's in the low 10's an 9's....
Which NA cars have 5.3L heads and are running 10's and 9's?
EDIT: Got the 5.3 and 5.7 backwards.
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Originally Posted by JoSeY
George had 5.3's.....it's all about the valves...u MUST change out the valves to make'em run right
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Originally Posted by KingCrapBox
Most people I talk to say that 5.7 heads will out flow 5.3 heads pretty easily. I would think that milled 5.7 heads would be the best bet, because you would get the CFM numbers and the bumped compression.
Most 5.3 heads I've seen don't even flow 300 CFM.
Most 5.3 heads I've seen don't even flow 300 CFM.
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I'll put my stock compression 5.7 up against any 5.3. I'm not a big fan of higher compression on pump gas. I tune ALOT of packages and none yet have beat ours. Last 5.7 heads and TR224 cam we did put down 441rwhp and 415 lbs/ft Tq. That was through FLP headers and GMMG exhaust.
We are working with Phoenix Performance (SCCA racing) on an LS6 headed package that is going to rock!
We are working with Phoenix Performance (SCCA racing) on an LS6 headed package that is going to rock!
Last edited by mikey; 01-14-2004 at 06:55 AM.
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Originally Posted by PSU_Engineer
Hey Mikey,
That SCCA team wouldn't be Phoenix Motorsports would it??
That SCCA team wouldn't be Phoenix Motorsports would it??
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how hard is it to unshroud the valves...? not very...the only reason ur 5.3's outflowed is their smaller stock valve size...period...and I'm talking George C that's here on the board....you don't want me to go get a buncha back up cause I'll have him and about a dozen other people in here. Trust me I've seen them both work over at MTI (I live about 5miles away) and the 5.3's def. flow....
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Originally Posted by mikey
I'll put my stock compression 5.7 up against any 5.3. I'm not a big fan of higher compression on pump gas. I tune ALOT of packages and none yet have beat ours. Last 5.7 heads and TR224 cam we did put down 441rwhp and 415 lbs/ft Tq. That was through FLP headers and GMMG exhaust.
We are working with Phoenix Performance (SCCA racing) on an LS6 headed package that is going to rock!
We are working with Phoenix Performance (SCCA racing) on an LS6 headed package that is going to rock!
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Originally Posted by JoSeY
how hard is it to unshroud the valves...? not very...the only reason ur 5.3's outflowed is their smaller stock valve size...period...and I'm talking George C that's here on the board....you don't want me to go get a buncha back up cause I'll have him and about a dozen other people in here. Trust me I've seen them both work over at MTI (I live about 5miles away) and the 5.3's def. flow....
You said that the benefit of 5.3's over 5.7's was the compression that you gain from going with 5.3L heads, even though they're easily out-flowed by 5.7L heads. Why not get a set of 5.7L heads, port them to flow 320ish, and then weld material to the combustion chamber so that you get not only the awesome CFM numbers, but also the added compression from having the 5.7L's milled. Wouldn't that be the best worlds? That would save somebody from having to decide between having 300+ CFM flow numbers and more compression. They could simply have both.
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Hey Austin, you can post stuff like that on our board too you know...
Are you going for most HP you can get? Then use the 5.3L heads.
With using that cam, your gonna have to fly cut the pistons...
Are you getting those heads ported here in Columbus? Have they ever done LS1 heads before? If they say LS what?, then you might want to use a sponsor on here. Absolute Speed is good, a bunch of us in the club have them...
Are you going for most HP you can get? Then use the 5.3L heads.
With using that cam, your gonna have to fly cut the pistons...
Are you getting those heads ported here in Columbus? Have they ever done LS1 heads before? If they say LS what?, then you might want to use a sponsor on here. Absolute Speed is good, a bunch of us in the club have them...