LT4 Heads vs LT1 Heads
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On The Tree
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LT4 Heads vs LT1 Heads So im going to get a set to have a friend of mine in my car club, who happens to be a god with port n polishing heads, do whatever set i get...but i was wondering, is it really that big of a difference to go with the raised lt4s for port n polishing? or is it just a slight better gain?....also i would have to get the lt4 intake too correct?...well then how big of a performance gain would i notice with the ported lt4 heads and intake against the ported lt1 heads and stock intake? thanks guys!
- WIll
Ok apparently i just found out the lt4 intake has no gain over the stock lt1 intake...so that being learned..still..the difference between lt1 ported heads, and lt4 ported heads?
- WIll
Ok apparently i just found out the lt4 intake has no gain over the stock lt1 intake...so that being learned..still..the difference between lt1 ported heads, and lt4 ported heads?
LT4 has a better maximum potential..and flows better than the LT1 from the start.
(Visual Example LOL )
LT1 base <--------------------> Max
.....LT4 Base <--------------------------> Max
(Visual Example LOL )
LT1 base <--------------------> Max
.....LT4 Base <--------------------------> Max
On The Tree
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From: TEA
the lt4 in my opion is over kill for most applications anyway... i mean it's alot bigger but, don't flow alot more at least from my experiances. although they should do good in a strocker and/or power adder situation (N2o turbo supercharger)
they're also way more exspensive castings than say.. ones already on your car
and if your friend is a porting god he should be able to get in the 290-300 cfm range with a 2.02 valve and a 205cc intake runner lt1 casting of coarse
if he can't then we can
hope i helped! any more questions pm me or give me a call at tea ask for tony
they're also way more exspensive castings than say.. ones already on your car
and if your friend is a porting god he should be able to get in the 290-300 cfm range with a 2.02 valve and a 205cc intake runner lt1 casting of coarse
if he can't then we can
hope i helped! any more questions pm me or give me a call at tea ask for tony
Thread Starter
On The Tree
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Originally Posted by TD's z
the lt4 in my opion is over kill for most applications anyway... i mean it's alot bigger but, don't flow alot more at least from my experiances. although they should do good in a strocker and/or power adder situation (N2o turbo supercharger)
they're also way more exspensive castings than say.. ones already on your car
and if your friend is a porting god he should be able to get in the 290-300 cfm range with a 2.02 valve and a 205cc intake runner lt1 casting of coarse
if he can't then we can
hope i helped! any more questions pm me or give me a call at tea ask for tony
they're also way more exspensive castings than say.. ones already on your car
and if your friend is a porting god he should be able to get in the 290-300 cfm range with a 2.02 valve and a 205cc intake runner lt1 casting of coarse
if he can't then we can
hope i helped! any more questions pm me or give me a call at tea ask for tony
i believe he flowed 319 or 309 cfm on the last set of lt1 heads he did.
like tony said the lt4s are better, but in most cases they are overkill. they arent cheap as you have to buy them brand new. used isnt an option. if someone has a set they wont go for cheap and if someone has the engine they will not part it im sure. use the LT1s unless youve got major plans down the road and dont want to do heads more than once. if your going simple heads cam maybe even 383 just get the LT1s ported. oh and you have to use the LT4 intake with the LT4 heads. no way around that.
Thread Starter
On The Tree
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Originally Posted by 5432LT1
i believe he flowed 319 or 309 cfm on the last set of lt1 heads he did.
yeah youre right i just asked a guy in the club...it was 309 or something but they had it measure wrong or whatever that means? ended up being late 280s...they told me that its pretty close to impossible to get them over 300
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On The Tree
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From: Choctaw, OK
Originally Posted by TD's z
the lt4 in my opion is over kill for most applications anyway... i mean it's alot bigger but, don't flow alot more at least from my experiances. although they should do good in a strocker and/or power adder situation (N2o turbo supercharger)
they're also way more exspensive castings than say.. ones already on your car
and if your friend is a porting god he should be able to get in the 290-300 cfm range with a 2.02 valve and a 205cc intake runner lt1 casting of coarse
if he can't then we can
hope i helped! any more questions pm me or give me a call at tea ask for tony
they're also way more exspensive castings than say.. ones already on your car
and if your friend is a porting god he should be able to get in the 290-300 cfm range with a 2.02 valve and a 205cc intake runner lt1 casting of coarse
if he can't then we can
hope i helped! any more questions pm me or give me a call at tea ask for tony
Dave
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LT4 castings have more potential than LT1 castings. Out of the box the LT1s flow roughly 215 CFM @ 0.5 inches lift. LT4 castings flow 250 CFM @ 0.5 inches lift. Out of the box, that is slightly better than stock '98-'00 LS1 heads.
LT1 head flow data: http://www.chevyhiperformance.com/te...98/index4.html
LT4 head flow data: http://www.chevyhiperformance.com/te...98/index5.html
LS1 head flow data: http://www.chevyhiperformance.com/te...98/index6.html
Remember also that LT4 castings come with 195 cc intake runners versus 170 cc for the LT1. Most LT1 heads that have been fully ported and polished flow 270-290 CFM max. LT4 castings can flow 300+ CFM when properly ported. If you can get a used set for a decent price, go with the LT4s.
LT1 head flow data: http://www.chevyhiperformance.com/te...98/index4.html
LT4 head flow data: http://www.chevyhiperformance.com/te...98/index5.html
LS1 head flow data: http://www.chevyhiperformance.com/te...98/index6.html
Remember also that LT4 castings come with 195 cc intake runners versus 170 cc for the LT1. Most LT1 heads that have been fully ported and polished flow 270-290 CFM max. LT4 castings can flow 300+ CFM when properly ported. If you can get a used set for a decent price, go with the LT4s.
Last edited by METALBEAST; Aug 26, 2004 at 06:46 AM.
Originally Posted by TD's z
hope i helped! any more questions pm me or give me a call at tea ask for tony
Strange,... best I got out of my stock casting '94 LT1 heads was 265 CFM @.600 and 260 CFM @.550.
Either my heads suck, or I'm the only one not inflating my numbers.
(or the only one who had them on an honest flow bench)
Either my heads suck, or I'm the only one not inflating my numbers.
(or the only one who had them on an honest flow bench) Thread Starter
On The Tree
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Originally Posted by METALBEAST
LT4 castings have more potential than LT1 castings. Out of the box the LT1s flow roughly 215 CFM @ 0.5 inches lift. LT4 castings flow 250 CFM @ 0.5 inches lift. Out of the box, that is slightly better than stock '98-'99 LS1 heads.
LT1 head flow data: http://www.chevyhiperformance.com/te...98/index4.html
LT4 head flow data: http://www.chevyhiperformance.com/te...98/index5.html
LS1 head flow data: http://www.chevyhiperformance.com/te...98/index6.html
Remember also that LT4 castings come with 195 cc intake runners versus 170 cc for the LT1. Most LT1 heads that have been fully ported and polished flow 270-290 CFM max. LT4 castings can flow 300+ CFM when properly ported. If you can get a used set for a decent price, go with the LT4s.
LT1 head flow data: http://www.chevyhiperformance.com/te...98/index4.html
LT4 head flow data: http://www.chevyhiperformance.com/te...98/index5.html
LS1 head flow data: http://www.chevyhiperformance.com/te...98/index6.html
Remember also that LT4 castings come with 195 cc intake runners versus 170 cc for the LT1. Most LT1 heads that have been fully ported and polished flow 270-290 CFM max. LT4 castings can flow 300+ CFM when properly ported. If you can get a used set for a decent price, go with the LT4s.
Originally Posted by 5432LT1
You wouldnt know the casting numbers for the LT4 heads would you?
The head casting number for the LT4 heads is 10239902 if I am not mistaken.
TECH Enthusiast
Joined: May 2004
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From: St. Peters, MO
I don't have a LT4 intake on my LT4 heads. It is visa versa...lt4 intake requires heads but the lt1 intake will work on lt4 heads. At least as far as I know. Unless there is some spacer in there or something...i didnt do the work when the heads were replaced. Oh yeah I got mine for 600 bucks complete off ebay. If you can get them for a decent price...go ahead. Otherwise get the stockers ported.
Staging Lane
Joined: Feb 2004
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From: In the shadows
Originally Posted by TWS
Strange,... best I got out of my stock casting '94 LT1 heads was 265 CFM @.600 and 260 CFM @.550.
Either my heads suck, or I'm the only one not inflating my numbers. (or the only one who had them on an honest flow bench)
Either my heads suck, or I'm the only one not inflating my numbers.
(or the only one who had them on an honest flow bench)
Your not getting over 280's with lt1 heads on a 2.020 @ .550 lift. And you can match up LT4 intake and LT1 heads you just have to raise the roof alot. LT4 is the way to go just keep it simple and be cost effective. 
Teching In
Joined: Jun 2004
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there is a website devoted to chevy casting numbers at www.mortec.com very thorough! I use them all the time here at AFR.
Just for reference the LT4 heads flow around 250cfm@0.500" lift while our comp package (which is 195cc like the LT4) flow's 275cfm@0.500" lift.
Had to add that last part, Right??
Just for reference the LT4 heads flow around 250cfm@0.500" lift while our comp package (which is 195cc like the LT4) flow's 275cfm@0.500" lift.
Had to add that last part, Right??
Originally Posted by 5432LT1
Where could i go to check that out..cause someone else told me they were 10239906
http://www.geocities.com/meanracing/...ngNumbers.html
Teching In
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I have a question... On the LT4 heads vs the LT1, do you sacrifice low end torque? In my application, torque's as or more important than horsepower. I can almost garuntee I'm carrying more car than anyone else on here.
Joined: Nov 2001
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From: LT1 land...the "409" of the 90s!
we have yet to really make more HP with a set of ported LT4 head then a set of ported LT1 heads....but we are working on it 
The killer seems to be the intake. We should be testing a new intake I built very soon
The killer seems to be the intake. We should be testing a new intake I built very soon