Checked out GM powetrain website and noticed the 4800 has 275hp and 290tq. My 91 LB9 has 205hp and 285tq. My engine is bigger, port injection and a tuned intake and yet it has 70hp less. What's so great about the LS1? Why does it have so much more power and why does my Lb9 compare so poorly?

I am not 100% sure about the truck engines, but the F &Y body LS-1's are also TPI. The thing about the LS-1 is that the runners are larger and shorter to support flow and promote the ramming or tuning in a different RPM range than with the L98 . Add to that the additional tech. that is out regarding the heads, cam, etc., and you get a a more powerful engine. Unfortunately, this is a pretty "in a nutshell" answer, but I think you probably get the idea. This should help: http://www.bgsoflex.com/intakeln.html

There's so many differences about the LS1 that it'd be virtually impossible for any single person to hit them all. Some simple, some massive. An aluminum block, an ecm that can tell you what cylinders are a little lower on power, a whole new design on heads, no distributor, and thank *** no optispark. The LS1 is an engineering marvel.

Something isnt right here. An LB9 is not bigger than a LS1, the LS1 is 346 cubes, 41 more than a 305. You said 4800? I dunno why, but looking at that and the HP/TQ numbers... is this a 6 cylinder engine youre referring to?

the 4800 is the smallest v8 for the trucks. it is based on the ls1, called the lq4. i think it has the same bore as the ls1 but a different crank. that's all i can think of now.

Makes a little more sense... whats the cubes? Is it 4.8L? Its not a LS1, thats for sure.

cubes are around a 290ish maybe a 299 or 298? its not to far ahead of the new inline 6 4.2l @275h/270t. i do like the diff. combo's of small blocks out there. makes an engine for everybody's needs. 5.3l is like a 325in. or 326in. really close to the old 327.

also somebody said it's like tpi, well not really. tpi runners are long at 21in. lt1 's are short at 3in. and ls1's are 14in. so they are tuned i guess but for high rpm power. hence the low torque numbers on a 4.8l. i have heard that truck ls-variants have a diff. intake than the ls1's. i'm sure they are still for topend but maybe longer than normal ls1's. i know the intakes won't fit under a 4th gen.'s cowl.

Keep in mind everybody that the "tuning" is not stricktly the length, the diameter as well plays a huge role. A tpi of the same length with AS&M runners does what?

just like tpi_roc said, there are so many things different compared to your LB9 motor. You could see that the 4800 has bigger intake and exhaust valves than your 305 heads. The intake runners are bigger. The camshaft is more aggressive and ............................. The list just goes on and on.

does anyone have the web adress for those as&m runners??

http://www.azspeed.com/

greatly apprciated!

I have a 2000 Silverado with the 4800 in it. Bear in mind this is a 4wd truck that weighs 5000 lbs with a full tank of gas & me in it (verifed on a truck scale at the local stone dealer). This truck has twice the balls of my last truck, a 305 TBI 2wd & will tow my Camaro & trailer all day with the AC on. It would give more than a few 3rd gens a run for the money. All from 292 cu in. Aluminum heads, roller rockers, sequential EFI, 8 ignition coils, plus a ton of other changes.

The heads probably flow 30% or more than your LB9's or any head that came stock on 3rd gens. You ever notice the stock LS1 heads flow better than most aftermarket aluminum heads. That's why they can make 400+ hp on stock headed LS1's. Those truck engines are just a smaller version of the LS1, same technology though.