Difference between an LT1 & L98?
Thread Starter
Racer
Joined: Jun 2009
Posts: 268
Likes: 1
From: Indianapolis, IN
St. Jude Donor '12
Difference between an LT1 & L98?
L98-
230 HP
330 Torque ft. lbs
5.7 L
LT1-
300 HP
330 Torque ft. lbs
5.7 L
It seems like the L98 and LT1 are mostly alike except for the difference in HP and compression ratio and the LT1 has a optispark while L98 doesn't..
In other words, what makes the LT1 get 300 that the L98 doesn't have? How can a L98 be modded to "become" a LT1?
230 HP
330 Torque ft. lbs
5.7 L
LT1-
300 HP
330 Torque ft. lbs
5.7 L
It seems like the L98 and LT1 are mostly alike except for the difference in HP and compression ratio and the LT1 has a optispark while L98 doesn't..
In other words, what makes the LT1 get 300 that the L98 doesn't have? How can a L98 be modded to "become" a LT1?
Drifting
Joined: Dec 2007
Posts: 1,329
Likes: 17
From: woodbury new jersey
they can never be the "same" because the lt1 has reverse flow cooling where as the regular sbc does not. id say one of the biggest advantages the lt1 has over the l98 is the intake. the l98 runs out of steam around 4500rpm due to the intake design, where the lt1 can rev a bit higher.
Advanced
Joined: Nov 2008
Posts: 85
Likes: 1
Those numbers are not quite right....l98 changed a bit over the years, but for 1989
245hp, 340tq.
LT1 looks correct at 300hp, 330tq.
I agree with everyone's comments, but would say the most restrictive issue for l98 is the Exhaust (single, 21/4 inch, 3 cats, 2 y's) vs. LT1 true dual exhaust 2 3/4.
Next up would be the intake issues (Long tube sized for 305 on the l98). Then of course the heads flow better on an LT1. Cam profiles are better on the lt1 as well.
245hp, 340tq.
LT1 looks correct at 300hp, 330tq.
I agree with everyone's comments, but would say the most restrictive issue for l98 is the Exhaust (single, 21/4 inch, 3 cats, 2 y's) vs. LT1 true dual exhaust 2 3/4.
Next up would be the intake issues (Long tube sized for 305 on the l98). Then of course the heads flow better on an LT1. Cam profiles are better on the lt1 as well.
L98-
230 HP
330 Torque ft. lbs
5.7 L
LT1-
300 HP
330 Torque ft. lbs
5.7 L
It seems like the L98 and LT1 are mostly alike except for the difference in HP and compression ratio and the LT1 has a optispark while L98 doesn't..
In other words, what makes the LT1 get 300 that the L98 doesn't have? How can a L98 be modded to "become" a LT1?
230 HP
330 Torque ft. lbs
5.7 L
LT1-
300 HP
330 Torque ft. lbs
5.7 L
It seems like the L98 and LT1 are mostly alike except for the difference in HP and compression ratio and the LT1 has a optispark while L98 doesn't..
In other words, what makes the LT1 get 300 that the L98 doesn't have? How can a L98 be modded to "become" a LT1?
Max G’s
Joined: Nov 2008
Posts: 2,751
Likes: 78
From: Monroe OH
NCM Sinkhole Donor
L98 in 1991 was either 245hp/345lbft or 250hp/350lbft depending on which rear ratio u had. L98 had better exhaust design except for having 3 cats. Better scavaging effect with the y-pipe up front vs true dual. If you are concerned about performance just concentrate on your torque and run your car in the peak range.
Melting Slicks
Joined: Mar 2003
Posts: 2,512
Likes: 49
From: Franklin IN
If your looking for horse power out of the box go with an LS-2. I have a 87 and a 99. My stock LS-1 will keep up with a Lingenfelter Preped Super Charged LT-1. I had my L-98 rebuilt a number of years ago and it is just waiting for me to get the rest of the car done otherwise I'd be out looking for a LS motor.
Safety Car
Joined: Sep 2010
Posts: 3,752
Likes: 190
From: Indiana PA
LT1 makes more power with more compression which is possible from reverse flow cooling. MUCH better flowing heads, LT1 heads out flow the famous Bow Tie race heads, better intake, exhuast, throttle body, just about everything assciated with air in your engine is better in a LT1.
The cam profile is also a little bit racier.
The LS1 makes more power than the LT1 with a similar cam profile thanks to WAY WAY WAY better flowing heads, intake, etc...
The current LS3 heads make the LS1 heads look like crap.
Airflow is the key to HP and torque production in an engine. It is an air pump.
The cam profile is also a little bit racier.
The LS1 makes more power than the LT1 with a similar cam profile thanks to WAY WAY WAY better flowing heads, intake, etc...
The current LS3 heads make the LS1 heads look like crap.
Airflow is the key to HP and torque production in an engine. It is an air pump.
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Team Owner
Joined: Sep 2001
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From: Athens AL
C7 of the Year - Unmodified Finalist 2021
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The intake design basically makes the difference. Cam profiles are not very different.
Thread Starter
Racer
Joined: Jun 2009
Posts: 268
Likes: 1
From: Indianapolis, IN
St. Jude Donor '12
Would adding a modified LT1 intake while running stock exhaust system be OK? It is kinda hard to find a set of headers to fit a 85 for street use since most of them don't have the right backpressure for low rpms
Team Owner
Joined: Sep 2001
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From: Athens AL
C7 of the Year - Unmodified Finalist 2021
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Would adding a modified LT1 intake while running stock exhaust system be OK?
It is kinda hard to find a set of headers to fit a 85 for street use since most of them don't have the right backpressure for low rpms
Burning Brakes
Joined: Jan 2007
Posts: 1,093
Likes: 0
From: Spring City Tn
L98 in 1991 was either 245hp/345lbft or 250hp/350lbft depending on which rear ratio u had. L98 had better exhaust design except for having 3 cats. Better scavaging effect with the y-pipe up front vs true dual. If you are concerned about performance just concentrate on your torque and run your car in the peak range.
Melting Slicks
Joined: Dec 2008
Posts: 2,772
Likes: 64
From: Mystic CT
the L98 first generation sbc is probably the most supported engine by aftermarket ever built. Lots of parts choices and much cheaper than anything else. If the LT1 was such a great idea why did it get discontinued after 4 years? Why in the world would you put an ignition system in an engine that can't get wet and ofer zero increase in performance???
Team Owner
Joined: Dec 2000
Posts: 21,094
Likes: 282
From: Phila., PA burbs
the L98 first generation sbc is probably the most supported engine by aftermarket ever built. Lots of parts choices and much cheaper than anything else. If the LT1 was such a great idea why did it get discontinued after 4 years? Why in the world would you put an ignition system in an engine that can't get wet and ofer zero increase in performance???
Melting Slicks
Joined: Dec 2008
Posts: 2,772
Likes: 64
From: Mystic CT
Team Owner
Joined: Sep 2001
Posts: 62,143
Likes: 1,730
From: Athens AL
C7 of the Year - Unmodified Finalist 2021
C4 of Year Finalist (performance mods) 2019
There wasn't much CFD modeling until the 1990s. LT1/4 was designed in the early-mid 80s. When they figured out how to build an LS intake and heads that got both HP and good low-end, the LT1 was doomed.
Thread Starter
Racer
Joined: Jun 2009
Posts: 268
Likes: 1
From: Indianapolis, IN
St. Jude Donor '12
the L98 first generation sbc is probably the most supported engine by aftermarket ever built. Lots of parts choices and much cheaper than anything else. If the LT1 was such a great idea why did it get discontinued after 4 years? Why in the world would you put an ignition system in an engine that can't get wet and ofer zero increase in performance???
Honestly, I've heard way too many people groan upon hearing that I have an L98 in my car. I just brush it off because I know I'm happy with my reliable engine and I know that I can mod it to beat a LT1 someday
Team Owner
Joined: Oct 2004
Posts: 81,241
Likes: 3,063
From: altered state
St. Jude Donor '05
Ok 5 whatever..LOL opti-spark is actually optional-sparks as in it might and it might not in 10 minutes later.. No way I would own one.
Dave
Dave
& 
Trust those things far as I can throw em.
Prices on those is SO tempting and lots to like about the cars its just that system they have on there, no way. Its as bad as the L98 intake lol.