jsawduste

Just a couple comments from a LSx newb. Not to be taken as a bitch or rant. I just want to understand the thoughts here.

This forum seems to be very pro 5.3/6.0. Which is great. These are super engines. Plenty of good parts out there to make a real runner. Be it a stroker, FI, or simple cam and headers.

What I do not understand is the seemingly dislike of the BB engines. Granted they can weigh more but the power potential is so much greater. With a decent set of OEM heads, cam, intake for can surpass the power of a well built LSx truck engine.

Example on the wild side would be a Dart 572/581 etc. A prepped short block can be had for 4,500 bucks. Add a set of JY oval port heads. A decent cam and you will be well over 600 horse (that is a conservative number) and have a torque curve as flat as Kansas.

A recent thread I started about putting together a strong torque engine for my tow rig had folks leaning towards a $6000 FI to get good low RPM numbers. A few even suggested doing a 408/FI which would up the price another bunch. But still fall short of what a big inch BB could do torque wise.

BB fuel injection is not hard or terribly expensive to do. So even here we are at a crossroads.

Could someone please explain why the 5.3/6.0 engines are so much better ?

MikeGyver

iTrader: (5)

This forum was spun off from LS1 Tech. there were enough guys hot-rodding LS based trucks to warrant starting a new web site. Hence the bias toward LS-engined trucks.
Everybody already knows that big blocks are much better, you won't stir any controversy there. We are too jealous of them to even mention them much, though. I'm sure others will back up my statement.

00ChevyScott

iTrader: (10)

lol big blocks...

jsawduste

And this makes perfect sense. A good answer.

Kinda like in Rome do as the Romans do.

I will certainly not dispute that the LSx engines have some distinct design advantages. But if it is sheer power you are looking for it is hard to beat cubic inches.

Thanks !!

Chevy Cowboy

iTrader: (5)

It kinda goes with the " why build a fast truck when you can build a even faster car for less money" its different, more of a challenge, etc

wastedrubber

iTrader: (10)

big blocks have that old school cool to 'em, and they're definitely still loved. but with these LS motors there's good power available at fairly reasonable prices and still reasonable gas mileage. not great, but better than a BB is gonna get.

TurboGibbs

iTrader: (6)

The Dart 571 would be awesome, but he said it best. It's the gas mileage advantage and cost.

Put it this way. You can build reliable 1000 hp with stock gen3 rockers, blocks, cranks, coil packs and wires, timing chain and gears. About the only thing you need to change about the fuel system is the injector size and the fuel pump/pumps. Factory computer ect... The light weight valvetrains can support over 7000 rpm with nothing more than a good $100 or so set of pushrods and good springs. You can't support 7000 rpm on a hydraulic BB cam. The spring rates have to be too high to move the heavy valvetrain and would compress the lifter. Then you have to run a solid lifter which takes your DD reliability away. And you'd need a $500 set of red-zone lifters and tool steel springs.
If you build a BB just add up how much you are going to have to spend in the valvetrain, distributor and ignition system. Then consider the $3000+ you will have to spend on a complete fuel injection system from fuel pump to the computer.
See, that $6000 supercharger, $350 cam and another $3-400 for pushrods and springs on a stock bottom end 6.0 pushing 500/500 at the wheels don't seem to bad. Oh, and knocking down 17-19 mpg on the highway.

Here's some proof of the potential. It's a junkyard 5.3 with a z06 cam and springs. Completely stock running stock GM cam and valve springs.
https://www.performancetrucks.net/fo...light=fairmont

TurboGibbs

iTrader: (6)

Still confused?

jsawduste

So not all.
Really appreciate the thoughts and wisdom you folks have been kind enough to share.

No doubt the LSx engines are marvels of modern day engineering. They have there place in the market and do a darn good job at it.

Indeed with a few mods they can be made to perform quite well.

Whereas the "old" BB`s are not nearly as advanced. There are some pretty fancy parts out there. Granted not as many as the venerable SBC or LSx

Surprisingly with the right combination of new and old they to can be made to run pretty efficiently.

Boils down to just what you want the engine to do and how you want to do it. In my case, a low RPM torque monster, it is hard to substitute sheer cubic inches.

Thanks guys for the help !!

TurboGibbs

iTrader: (6)

Exactly. I love low rpm torque monsters. I've grown up exposed to all GM performance and some others. My brother has a 468 in a 68 vette tri power that put down 488/491 at the wheels. The 3x2's are really holding him back since he wants to keep the factory BB hood. After droping a (heavy ***) valve, he's building a 498 bottom end for it. Very fun in 3200lb convertable.

It's fun going to the dyno with an old school and they always ask what you expect out of it. When you tell them they kinda smirk and after it is over they are humbled. If you know what you are doing with the old stuff you can make some serious power. Many though, have high expectations from what they've read and end up disappointed.