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Discussion Starter #1
This was in my GM Chevy Resto package and shows the LT1 peak hp at 315. :huh: I wonder if maybe the LT1 was detuned to make the 385hp in the LT5 look more attractive to buyers?

What do you folks think??

And what about the L98 peak is it right?

 

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it didn't even show that...........something is screwy cause I had a 70 LT1 and it was a bear of an engine. Would be interesting for some one to really look into it. Hey C3 guys!!:surprised
 

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The 91 L98 is supposed to be 250 hp and that shows only 240. My dyno sheet shows about the same amount of hp as was advertised but my torque was way off. I have about 50+ ft.lbs. more than advertised. :D

That's why they call the L98 the "Stump Puller". :thumbsup:
 

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first your compareing apples and oranges

the 1970 LT1 is a gen 1 engine with the hp measured at the flywheel

the 1992 LT1 is a gen II engine measured at the rear wheels

the L98 is a TPI gen 1 engine but designed not for max power but max torque and mileage, it was never intended to make max power in stock form


the engines can ALL make over 450hp with the correct mods , but they were all designed for differant rpm ranges.

current tech. limits the engines to about 7000rpm without EXPENSIVE and extensive mods, the TPI L98 intake is designed for 4500rpm max so thats the big limiting factor on that engine!
all the engines are under cammed but the 1970 LT1 is better cammed than the other two if max HP is the goal ) but modern cams can GREATLY increase all three engines performance
 

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Discussion Starter #5 (Edited)
grumpyvette said:
first your compareing apples and oranges

the 1970 LT1 is a gen 1 engine with the hp measured at the flywheel

the 1992 LT1 is a gen II engine measured at the rear wheels

the L98 is a TPI gen 1 engine but designed not for max power but max torque and mileage, it was never intended to make max power in stock form


the engines can ALL make over 450hp with the correct mods , but they were all designed for differant rpm ranges.

current tech. limits the engines to about 7000rpm without EXPENSIVE and extensive mods, the TPI L98 intake is designed for 4500rpm max so thats the big limiting factor on that engine!
all the engines are under cammed but the 1970 LT1 is better cammed than the other two if max HP is the goal ) but modern cams can GREATLY increase all three engines performance
I was not comparing anything. This is what I believe to be a GM LT1 preproduction internal document that I thought was interesting.

What on this document leads you to believe that one curve is Rear Wheel and the other is Flywheel HP? My LT1's 300 HP (factory rated) was measured at the Flywheel.

Yes, with $$$ you can make HP with any IC engine.

I'm looking at this from a production part's only stand point... why does this document show the gen II LT1 hp @ 315??? maybe it lost the 15 hp in the manufacturing tolerances, maybe in the exhaust system I don't know, but I think it's an interesting topic of discussion.

:buhbye:
 

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All I know is that my 70 LT1 could kick ass, but then I think my LT4 will also. The 70 was a hang on and pray type of speed where as the GS is soooooooo much more refined. Guess thats what 26 years of making engines do for you. Thanks grump, Just couldn't figure it out
 

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If you look at the right side, you will see that the HP is BHP (brake HP). If I remember correctly, that was what changed in measuring HP, I think in the mid-70's. Before that, it was gross HP. My understand was if all the big HP motors from the 60's were measured in BHP's, their numbers would be much lower then advertised, due to the new measurement.

I doubt that the gen II LT1 is rear wheel because my dyno pull, with aftermarket exhaust, yielded 266 RWHP.
 

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The statement that gen II was rear wheel HP is wrong. Auto makers NEVER used a chassis dyno to rate engines output, only engine dyno. I don't know about the newer LT1 being detuned the numbers for the newer LT1 look right on to me they were rated at 300HP and 330 TQ.
 
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