Vombrown
Mountain Man
While I'm at it, which headers are working in our trucks? I'm seeing block huggers and the corvette headers in most of the stuff I'm reading. Gimme some input here.
Was talking to a mutual of @mrk5 today. He used the DIY4x engine mounts to keep the bell mating surface in the stock location.
Nice looking mounts for the price
I'm sure things have probably moved forward since I did my research about a cam swap on my 5.3 a couple of years ago. The jist comes down to this, Hot Rod did a huge cam comparison on the 5.3 specifically and one major factor came out. Every and I mean EVERY cam they compared against the stock LM7 (5.3) cam LOST torque below 2500 rpm. Cams tested were the LS1, LS2, LS3, LS6, LS7, LSA, LS9, L33, LQ9 and three Crane Cams. All moved the torque peak up by as little as 200 rpm to 900 over the stock LM7. Incidentially, the LQ4 cam made similar numbers to the LM7.
For me any cam change was a move in the wrong direction of the torque curve. If I was putting the 5.3 into my Nova, sure any one of those would wake it up on the road. Bottom line, the stock 5.3 cam is a little measly grind, but for a heavy truck playing off road I needed all the torque I could get down as low as I could. Now I go back to my first statement, I looked this up a couple years back. Somebody might be making better cam now, but I've not looked for it.
http://www.hotrod.com/articles/ls-cam-test-comparison/
And if we’re comparing factory GM engines, yes most those older engines are turds, especially the TBI engines which suck ass.Maybe what I meant could better be expressed in power/weight ratio.
If the power/weight ratio is low, low end torque matters a lot. If you can't get into the power range, the top end doesn't help. That's amplified by not having enough gears. Sure you can spin the engine fast with good top end power, then shift and it falls on it's face. The transmission gaps are either too big, or the torque produced is too little (either the transmission ratios fault or engine torque curve).
With my K30 in my avatar (12V Cummins), I consider it "underpowered" while towing. Not that I'm not happy with it, I love it, but ~450 diesel HP towing 14K combined isn't a rocket ship. It tows great with a 5 speed (not worth swapping to a 6 speed for my use) but I can fully appreciate why tractor trailers have so many gears. Same story, low power/weight so they make up for it with lots of gears to keep the engine at peak torque. Underpowered sounds weird for a turned up Cummins that I can tow my Blazer/buggy up anything but the I70 passes at 70 mph easily in 5th, but to me it needs the low end torque because 450hp @ 14K is low power/weight and only has 5 forward gears.
My Blazer/buggy is a different story, it's much lighter with a lot more horsepower. With the bigger cam (in a 6.0 w/317 heads), it trades low end torque, but it isn't even close to needing more low end. The power/weight is pretty good on that rig, the low end torque means next to nothing. Sure, the peak torque may have moved up, but as long as you have enough to get going everything else is gravy. I would say the point on that thing, is that as long as you have enough low end to keep that side happy, the higher end horsepower is a huge gain.
A 60's-80's GM 350 had what, 250 ft. lbs. of max torque? A stock 6.0L makes more than 300 ft. lbs. at any RPM that would be used, and more than that off idle, with double the horsepower.
Maybe what I meant could better be expressed in power/weight ratio.
If the power/weight ratio is low, low end torque matters a lot. If you can't get into the power range, the top end doesn't help. That's amplified by not having enough gears. Sure you can spin the engine fast with good top end power, then shift and it falls on it's face. The transmission gaps are either too big, or the torque produced is too little (either the transmission ratios fault or engine torque curve).
With my K30 in my avatar (12V Cummins), I consider it "underpowered" while towing. Not that I'm not happy with it, I love it, but ~450 diesel HP towing 14K combined isn't a rocket ship. It tows great with a 5 speed (not worth swapping to a 6 speed for my use) but I can fully appreciate why tractor trailers have so many gears. Same story, low power/weight so they make up for it with lots of gears to keep the engine at peak torque. Underpowered sounds weird for a turned up Cummins that I can tow my Blazer/buggy up anything but the I70 passes at 70 mph easily in 5th, but to me it needs the low end torque because 450hp @ 14K is low power/weight and only has 5 forward gears.
My Blazer/buggy is a different story, it's much lighter with a lot more horsepower. With the bigger cam (in a 6.0 w/317 heads), it trades low end torque, but it isn't even close to needing more low end. The power/weight is pretty good on that rig, the low end torque means next to nothing. Sure, the peak torque may have moved up, but as long as you have enough to get going everything else is gravy. I would say the point on that thing, is that as long as you have enough low end to keep that side happy, the higher end horsepower is a huge gain.
A 60's-80's GM 350 had what, 250 ft. lbs. of max torque? A stock 6.0L makes more than 300 ft. lbs. at any RPM that would be used, and more than that off idle, with double the horsepower.
So I'll throw this out there. I'm not looking to build a high HP truck, I just know I'm not up on the LS parts that are available and some of you guys are. It's starting to sound to me like the bottom end crane cam might be just the ticket. Intake wise, I have no idea. Most of the performance intakes look cool but honestly I don't care for the cost. I'll be sourcing something that was stock on something versus a performance intake I think. This relatively inexpensive engine swap is turning into a good way to loose a few thousand dollars.....and I still need to get a wiring harness and computer. LOL
Cost of acquisition for the engine, gas pedal, exhaust, fans, hoses, engine .mounts, air intake, pinout and computer work all should be figured. Most guys I've talked to said they added $1000+ in miscellaneous stuff to get it running.