MeanMachine350

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?

littlesk8cracker

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.

cv67

Put a converted LT1 intake or a miniram on your L98 and youll be right about there.

BADDUCK

Main differences: intake, exhaust, cam, heads.

tmichaud

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.

l98tpi

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.

87bob

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.

93Rubie

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.

vader86

LT1 has short runners, L98 has long runners. Long runners= high port velocity at low rpm=torquey, short runners=high port velocity at high rpm=HP. Put a MR on an L98 engine, tune it, and you're very close.

The intake design basically makes the difference. Cam profiles are not very different.

MeanMachine350

By converted LT1 intake you mean the stock LT1 intake won't fit a L98 without modifying it?

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

vader86

Yes, it wont work on the L98 out of the box.

Yes

What is this "right backpressure" nonsense? Delete that thinking from your brain. Your 85 does not need backpressure.

tnz5106

And the L98 was the 2nd most awesome engine to the eye, the only one more awesome was the LT5!!!!! The lt1 is very plain.......sorry c4 brothers!!

ddahlgren

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???

TA

5 years actually, but who's counting.

ddahlgren

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

vader86

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.

cmjuhl

1990 L98 ENGINE SPECS.


ZSA L98 350-cid 245-t/250-hp V-8 9.5:1
ZSB L98 350-cid 245-t/250-hp V-8 9.5:1
ZSC L98 350-cid 245-t/250-hp V-8 9.5:1

cv67

You sure about that?

MeanMachine350

Then why does it seem like the LT1 is the 'holy grail' on this forum? I see a lot of people bashing L98s and saying they would much prefer a LT1 in their cars when a L98 can be more reliable?

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

cv67

&

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.