Difference between LT1 & LT4
Burning Brakes
Joined: Jan 2012
Posts: 1,191
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From: Gilbert AZ
2018 C1 of Year Finalis4
Thread Starter
Burning Brakes
Joined: Nov 2014
Posts: 920
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From: Stoneham, MA
Awesome information ColaBear. Thank You. Looks like the LT4 was built for higher top end RPM with the torque staying the same as the LT1.
Great reading :-)
Now, what bolt on products are there to increase the LT1's HP & how much can be easily be gained.
Great reading :-)
Now, what bolt on products are there to increase the LT1's HP & how much can be easily be gained.
Le Mans Master
Joined: Oct 2004
Posts: 6,314
Likes: 508
From: South-central Missouri
CHEAP - FAST - RELIABLE... Pick any two!
There is no easy way for this (former) SBC builder to answer that question..because "how much" and "easily gained" have a different meaning to everyone that asks that question.
But, for example, 425 HP at the crank for a second gen. LT1 can be had for around $2.200 using the HOT CAM formula, on the cheap (e.g., no new bearings, pistons, rings, repairs or extra machining, etc).
I've ground up enough SBCs to know that if you don't start with a goal and lay the groundwork down first (read: use all the right stuff), the project will be short(er) lived than you might want. Before you'd want to, you might find yourself going back into the motor to "do it right". Oh, and keep your AAA membership up to date. Just sayin...
Last edited by Paul Workman; Jun 27, 2016 at 12:22 PM.
Race Director
Joined: Oct 2011
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From: Dallas Texas
2025 C4 of the Year Finalist - Modified
longtube headers
Yes, I know you can install a cam for less, if you do it yourself, but at least with those two mods, you don't have to go deep into the engine.
Burning Brakes
Joined: Dec 2009
Posts: 1,143
Likes: 81
From: Finger Lakes Region, New York
Search the forum, TONS AND TONS of info regarding hopping up LT1's. Hell, search it on google, there is a ludicrous amount of info out there. Good luck!
Race Director
Joined: Apr 2000
Posts: 15,344
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From: Texas
I agree with the headers, but not with the 1.6rr's. Roller rockers basically net you no measurable HP increase. They aren't too expensive but you will not notice any difference in power. Better air filter/intake would be a better choice than rr's.
Search the forum, TONS AND TONS of info regarding hopping up LT1's. Hell, search it on google, there is a ludicrous amount of info out there. Good luck!
Search the forum, TONS AND TONS of info regarding hopping up LT1's. Hell, search it on google, there is a ludicrous amount of info out there. Good luck!
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Racer
Joined: Jul 2014
Posts: 266
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From: Philadelphia Pa
this is a decent article detailing mods and improvements based on those mods for an LT1 engine
Super Chevy LT1 Mods Part 2
Super Chevy LT1 Mods Part 2
Burning Brakes
Joined: Dec 2009
Posts: 1,143
Likes: 81
From: Finger Lakes Region, New York
His point is about the ratio. The stock LT1 has 1.5 rockers. Moving to 1.6 consistently nets 15hp at the rear wheels. It's like swapping in a slightly larger (more lift) cam. As for the roller element...I agree, if someone swapped in 1.5 full roller rockers or roller tip rockers, the gain would be minimal at best.
The small amount of lift a 1.6rr adds will not equate to 15rwhp. Most of the hp gained from a cam is in the duration not the lift. I even spoke to Lloyd Elliot about this in the past.
Le Mans Master
Joined: May 2005
Posts: 7,340
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From: Central Maryland
I'd swap to a higher-ratio gearset in the Dana before I did any mods to the engine. If that doesn't satisfy, then consider engine mods, but understand the can of worms you're potentially opening up if you wade into those waters.
Live well,
SJW
Live well,
SJW
Burning Brakes
Joined: Nov 2013
Posts: 914
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From: St. Petersburg FL
HOWEVER... there is a forum member with an LT1 who dynoed the car before and after installing just the 1.6 roller rockers (he didn't say if he changed the valve springs or not so I think we can assume he did not).
His dyno tests indicated a 10 HP gain at the rear wheels with the rocker arm change. Following is a link. His post is #6.
https://www.corvetteforum.com/forums...rs-in-lt1.html
Burning Brakes
Joined: Dec 2009
Posts: 1,143
Likes: 81
From: Finger Lakes Region, New York
I have to differ with you. Not only do you get a 7% boost in lift but you also get a 7% increase in duration. I installed Scorpion 1.6 roller rockers in my '96 LT1 along with LT4 valve springs. I'm not going to make any outrageous claims based upon my SOTP dyno but the car does feel more responsive and appears to get to 6K RPM before the electronics can stop it.
HOWEVER... there is a forum member with an LT1 who dynoed the car before and after installing just the 1.6 roller rockers (he didn't say if he changed the valve springs or not so I think we can assume he did not).
His dyno tests indicated a 10 HP gain at the rear wheels with the rocker arm change. Following is a link. His post is #6.
https://www.corvetteforum.com/forums...rs-in-lt1.html
HOWEVER... there is a forum member with an LT1 who dynoed the car before and after installing just the 1.6 roller rockers (he didn't say if he changed the valve springs or not so I think we can assume he did not).
His dyno tests indicated a 10 HP gain at the rear wheels with the rocker arm change. Following is a link. His post is #6.
https://www.corvetteforum.com/forums...rs-in-lt1.html
Also I'm pretty sure going from 1.5 to 1.6 roller rockers does not increase duration. How could they? Do they magically make the cam lobe bigger? No, they just get the valve to the higher lift faster and back to the seat faster.
If you change just the rockers the lifter is still going to ride on the same cam lobe and the only difference is how far the valve opens. Basically the 1.6 rockers are opening and closing the valve faster (netting no gain in duration), the valve will still open and close at the same time as the 1.5 rockers.
Also a 10hp increase could have easily been ANY other factor. Usually when ppl do a dyno pull 3 times all 3 reading are quite a bit different.
I would like to know exactly how the 1.6rr's increase duration? If I'm wrong I would like to be corrected. I just don't see how it's possible.
Burning Brakes
Joined: Nov 2013
Posts: 914
Likes: 277
From: St. Petersburg FL
Nope... it's not. I misspoke. Thanks for pointing out the error.
However, I think it's silly of you to stick to your "no HP gain" based upon how you feel about it when another Forum member says dyno results show otherwise.
Burning Brakes
Joined: Dec 2009
Posts: 1,143
Likes: 81
From: Finger Lakes Region, New York
I agree with a gain but not with a huge gain. Same idea as a CAI, everyone claims they give like 20-40hp at the wheels but it just doesn't make sense. Most "cold air" intakes suck hot air anyways, hence my skepticism.
Hey regardless of what I think if he got a 10whp gain with just a rocker swap then good for him. That's pretty good.