LT-4 conversion kit for LT-1
Advanced
Joined: Aug 2004
Posts: 65
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Originally Posted by steve9899
It's widely advertised as 125 HP. Now whether it gets 125HP in the real world is questionable (the test was with LTs and open exhaust), but it's a lot more than 30.
Also you can get the parts for quite a bit less than $2200 if you shop around.
Plus everybody always fails to realize that if you go the LT4 route you get to sell your LT1 heads and cam to recoup a little of the cost.
Also you can get the parts for quite a bit less than $2200 if you shop around.
Plus everybody always fails to realize that if you go the LT4 route you get to sell your LT1 heads and cam to recoup a little of the cost.
Safety Car
Joined: Apr 2003
Posts: 3,793
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From: VA
Originally Posted by Zix
Only the exhaust valves on the LT4 are special, as they are sodium filled. A heavy ported LT4 head will still outflow a similarly ported LT1 head. I have a set of stage 4 LT4 heads that flow a little over 315CFM...I haven't seen that out of LT1 heads before.
Yes it will outflow at any equivalent port.
But how much it outflows drops off with increased "stage" so the bang for the buck goes away.
Stock LT4 flows 30-40 more than LT1.
So just looking at the heads, it costs about $600 to get this 30-40cfm.
Stage 3 from moreperformance (just since they have the numbers available) LT4 outflows LT1 by 15, and the LT4 porting costs $100 more.
So now it's $700 for 15 cfm.
These are typical of numbers I've seen from other porters and from people posting their specific head flow numbers.
I have no knowledge of stage 4 numbers, so maybe the LT4 pulls back ahead at that level of porting.
For me, with the good prices I got on ebay, the LT4 option is a slightly better bang for the buck, at a low porting level. If I was doing a stage 2 or stage 3 port I would stick with the LT1 cores. OTOH, if I was going for no-holds-barred stage 4 type power, then I'd start with aftermarket heads.
Safety Car
Joined: Apr 2003
Posts: 3,793
Likes: 9
From: VA
Originally Posted by BDVETTE96
ok so why does the LT4 produce 330 hp and the Lt1 300? they use gm performance parts in this kit the same as the production upgrades used in the 96 grand sport. hense the 30 hp real world gains, how can it produce more? is there some magical cam there using that makes another 100 horsepower? highly unlikely that your going to get more than 30 since thats what the factory motor produced, and they sell the factory parts.
Drifting
Joined: Aug 2004
Posts: 1,830
Likes: 1
From: atlanta Georgia
well to clarify agian
the lt4 heads out flow lt1 ok but they dont out flow lt1 stg 3 heads
got it?
so for the $ get stg 3 vs stock lt4 heads
well I am trying to by lt4 heads to get stg 3 lt4 heads which out flow lt1 stg 3 heads.
but its alot more expensive to do that!!!
but yeilds a little bit more in hp!
do you understand?
the lt4 heads out flow lt1 ok but they dont out flow lt1 stg 3 heads
got it?
so for the $ get stg 3 vs stock lt4 heads
well I am trying to by lt4 heads to get stg 3 lt4 heads which out flow lt1 stg 3 heads.
but its alot more expensive to do that!!!
but yeilds a little bit more in hp!
do you understand?
Race Director
Joined: Sep 2004
Posts: 13,793
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From: St. Peters MO Sometimes you have to prove yourself by doing alot of killing or alot of dying...
I'm so confused... 
This is actually a pretty funny arguement.
Is this estimate based off the install of the Hotcam? I've seen the kits where you can add the hotcam, but the kit itself is just the heads and intake. I have an LT4... so I'd be hard pressed to think that the same heads and intake that I currently have installed on an LT1 will produce more power than what I can put out. That sounds really cocky and I really don't mean it to be...
This is actually a pretty funny arguement.
Originally Posted by Zix
An LT4 conversion kit gives you more than 30 at the wheels. It would likely (on average) bump a stock LT1 from the 260-270RWHP range to the 320-330RWHP range. All these kits (that I have seen) come with the LT4 Hot Cam kit, not the stock LT4 cam so there's a nice bump with the combination of the better flowing heads.
Drifting
Joined: Aug 2004
Posts: 1,830
Likes: 1
From: atlanta Georgia
the stg 3 lt1 heads flow WAY MORE than the stock lt4 heads!
thats just fact!
of corse stg 3 lt4 heads glow those out of the water!
now when Im talking about heads making more hp than the other im talkin about both with the same cam etc...
its not hard.
the stg 3 comes fully ported with larger valves and flows alot more air!
your friend
Sean
thats just fact!
of corse stg 3 lt4 heads glow those out of the water!
now when Im talking about heads making more hp than the other im talkin about both with the same cam etc...
its not hard.
the stg 3 comes fully ported with larger valves and flows alot more air!
your friend
Sean
Safety Car
Joined: Apr 2003
Posts: 3,793
Likes: 9
From: VA
Originally Posted by kwik_ta
I'm so confused... This is actually a pretty funny arguement.
This is actually a pretty funny arguement.As I said, do a little research. There is a post here on this conversion about once a week. And if you do a little googling you can find a lot more information.
Safety Car
Joined: Apr 2003
Posts: 3,793
Likes: 9
From: VA
Originally Posted by redbullapril23
the stg 3 lt1 heads flow WAY MORE than the stock lt4 heads!
thats just fact!
of corse stg 3 lt4 heads glow those out of the water!
now when Im talking about heads making more hp than the other im talkin about both with the same cam etc...
its not hard.
the stg 3 comes fully ported with larger valves and flows alot more air!
your friend
Sean
thats just fact!
of corse stg 3 lt4 heads glow those out of the water!
now when Im talking about heads making more hp than the other im talkin about both with the same cam etc...
its not hard.
the stg 3 comes fully ported with larger valves and flows alot more air!
your friend
Sean
Yes we're both ignoring the cam.
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Thread Starter
Racer
Joined: Dec 2004
Posts: 429
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From: Midddleburg FL
Sorry, didn't mean to start an arguement. Basically what I want to know is whats the best way to get around 330 rwhp. The only real factors are, of course, money, and the other is fuel mileage. I drive this car from FL to SC atleast 4-5 times a year. So basically I want to have my cake and eat it too. I know any uprgrades or mods that produce hp hurts fuel mileage, and I can live with that to a point. Right now I'm in the early planning stages. Just want to get as much info as I can and when the time and the money come, I'll know what I want. Thanks for the input. 
Safety Car
Joined: Apr 2004
Posts: 4,532
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From: Lahaina Hi
http://www.gmpartsdirect.com/results...ber=pk12550630
Comp cams bee hive springs 1.6 rr vigalant 2800 stall converter,3.54 gears.
Your hp is there should be good to 12.70.
Last edited by REDC4CORVETTE; Jan 4, 2005 at 04:09 AM.
Safety Car
Joined: Apr 2003
Posts: 3,793
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From: VA
Originally Posted by tm1995c4-LT1
Sorry, didn't mean to start an arguement. Basically what I want to know is whats the best way to get around 330 rwhp.
