OBD-1 LT-1 hp
Thread Starter
Burning Brakes
Joined: May 2009
Posts: 1,014
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From: Ft Wayne IN
OBD-1 LT-1 hp
What's the hp limit for a OBD-1, Lt-1 motor before program changes are needed? What about a strocker mod? I am shooting for 400hp with maintaiing good bottom end drivability. Is a 383 the way to go or can I achive this goal with cam and some head work? How much more compression can an LT-1 handle with pump gas?
Team Owner
Joined: Sep 2001
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From: Athens AL
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You dont understand, any changes can benefit from a computer reprogram. Things like intake porting or exhaust dont require a retune, but you can benefit from one.
My general advice is any internal engine work: cam, stroker, head changes, etc., does require a retune, a CUSTOM one done on a dyno preferably. If you dont, it will not run perfectly (bad idle, rich/lean) and youre leaving power on the table.
It is possible to get 400 hp at the crank from heads/cam changes. 400 at the wheels is possible, but another issue would be if you wanted to drive it everyday on the street in such a configuration on a 350. You will need the computer reflashed either way.
My general advice is any internal engine work: cam, stroker, head changes, etc., does require a retune, a CUSTOM one done on a dyno preferably. If you dont, it will not run perfectly (bad idle, rich/lean) and youre leaving power on the table.
It is possible to get 400 hp at the crank from heads/cam changes. 400 at the wheels is possible, but another issue would be if you wanted to drive it everyday on the street in such a configuration on a 350. You will need the computer reflashed either way.
Race Director
Joined: Jan 2005
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From: Slidell Louisiana
What's the hp limit for a OBD-1, Lt-1 motor before program changes are needed? What about a strocker mod? I am shooting for 400hp with maintaiing good bottom end drivability. Is a 383 the way to go or can I achive this goal with cam and some head work? How much more compression can an LT-1 handle with pump gas?
Power is made in the top end (heads/cam/intake/exhaust) more cubes just move the power to a lower rpm.
There are stock lower end LT1s that put out more horsepower than high dollar LT1 stroker builds.
I've been trying to get my 355ci corvette to hook up so I guess I have decent bottom end performance. My LT1 has 12.1:1 compression and runs on pump gas. One of the reasons I can run pump gas is I have a 23X 23X on a 110 LSA .61X lift cam, a big cam allows the use of pump gas since it lowers dynamic compression.
Oh I definately want to drive it on the street everyday........
Le Mans Master
Joined: Jul 2000
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From: Greenville SC
Plus the reverse flow heads allow more CR.
Even if you just change the cam, get at least a mail order tune. Your spending $, get the most out of it. My friend did just a hotcam change and exhaust, and he needed a tune.
Even if you just change the cam, get at least a mail order tune. Your spending $, get the most out of it. My friend did just a hotcam change and exhaust, and he needed a tune.
Thread Starter
Burning Brakes
Joined: May 2009
Posts: 1,014
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From: Ft Wayne IN
What's a 23x 23x 110 lsa ? I believe those are cam numbers but don't understand completely. Is the LT-4 cam good for bottom and midrange power or should I go bigger? don't want to loose to much bottom end. Did you have to run diff pistons to get that compression? If not what was done to get it, milled heads?
I wasn't planning on doing the motor this soon I wanted to do gears first but my rear main started to leak pretty bad all of a sudden and I belive my optispark distributor is due for an overhaul so with 130K on the motor I think my winter prject will be a rebuild.
I wasn't planning on doing the motor this soon I wanted to do gears first but my rear main started to leak pretty bad all of a sudden and I belive my optispark distributor is due for an overhaul so with 130K on the motor I think my winter prject will be a rebuild.
Last edited by C4vettrn; Sep 1, 2009 at 10:38 AM.
Team Owner
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From: Athens AL
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Pretty much anything you do is going to bump your top end and midrange, where the LT1 intake wants to make power. There is no way to improve low-end only, your cam is wimpy enough stock. Thats where the gears come in, thats why you should do that.
He is talking about a cam spec, intake/exhaust duration at .050" with a tight lobe separation. His particular specs are not important, but a cam with that much lift (.610+) and duration (230-239 on each side) is large and can make a lot of power. 230/244 is the duration spec on the CompCam 306 for example, and its a nasty cam for a 350 with a lot of lope.
He is talking about a cam spec, intake/exhaust duration at .050" with a tight lobe separation. His particular specs are not important, but a cam with that much lift (.610+) and duration (230-239 on each side) is large and can make a lot of power. 230/244 is the duration spec on the CompCam 306 for example, and its a nasty cam for a 350 with a lot of lope.
