I know how much the LG4 came with with everything hooked up, but I was thinking, what would the maximum Hp be for a freed up LG4....

SO, does anyone know the Gross Horsepower rating of the LG4 ('84 in particular or any for that matter)?

 

I beleive it was 155HP for that year but check the board's tech info section to be sure.

Open up the air cleaner, rejet the secondaries in the carb, replace the laughable 2 1/4" exhaust with typical 1 5/8" headers and a 3" cat and cat-back, bump the timing up 4* over stock and I think you'd be knocking on the door of 190-200 HP without ever taking the valve covers off.

Yes, the stock stuff is that restrictive. I'm working on a nearly identical 85 Z-28 with the LG-4 right now, seeing how far I can push it. It now burns the right rear tire to the ground on a hard 1st gear launch and gives it another good scratch shifting into 2nd. Before it wouldn't even sqeak the rears.

 

"Gross" is a pretty good description of LG4 HP...

Seriously, the 155 number is net. Gross flywheel horsepower doesn't really tell you much, though. But, add about 25%, that's fairly close.

 

Gross Hp is the engine w/o accessories or exhaust... the maximum you could get w/ completely stock engine...

The LG4 in '84 had 150 Hp and going by the 25% assumption it would have 187.5 Gross Hp... the single worst engine component would have to be the hilarious .350 lift cam...

 

Im sure gross power of the LG4 would be over 200hp. Probably 210. I've seen 60's muscle car engines bench dyno'd and one of them made 80hp more than GM claimed!

 

No way the LG4 is at 200 gross. How much horsepower does it take to turn a water pump? How about an alternator? Putting the exhaust through the entire exhaust system will kill some hp, but were still not talking about an extra 45 horses.

 

BTW, 60's muscle cars were still rated in gross horsepower.

 

the 60's muslce cars didn't lie as often or hardly ever as much as thought, it's just the way they posted the numbers. to long to explain. the LG4 test i have seen on a dyno went about 180 if i remember correctly. this was no accesories and with air cleaner and exhaust as gross was rated.

 

I meant to say, that they made 80hp less than GM claimed. Sorry.