[Tonz]

Hi I've been looking for a high hp replacement for my 350 sbc, ive considered a 400 but considering I'd need an aftermarket dart block on top of everything else to hopefully make 600hp reliably, it seems very expensive. Thats when i found this very inspiring article,

Vortec 5.3L - Big Bang - Truckin Magazine

Ever wonder how much boost will a stock 5.3L short-block withstand before the proverbial Big Bang and what is the resulting power output? The results will shock you so be sure to read our Vortec 5.3L Big Bang in issue 13 of Truckin Magazine.

www.trucktrend.com

Now obviously I'm not going for a "big bang" or 1300hp, nor am i looking to buy 118 octane race gas, but it got me thinking, could i pump a bunch of boost into an lm7, run it on e85, and meet my 600+hp goal reliably on some mild-ish upgrades to internals? If yes, what combination of internals/heads/intake etc. Should i go with? And what would go into converting this gas engine and fuel tank/pump/lines into one that runs on e85?

 

[matt167]

Yes, and the LM7/LR4/LQ4 and 9 can be wired with a flex fuel sensor which basically makes it E85 ready... Watch and look at Sloppy Mechanics on youtube and other places. It's pretty much all he does. The simple answer is turbocharging, 600hp is pretty mild. Many people will say a 5.3 or 4.8L are better boost engines than the 6.0L. 600hp can be met with any of them

 

[39 master]

From what I hear if you open the ring gap, add a cam with one turbo you will be there. Of course horses cost money, how many do you want? Your best bet is to do loads of research to see exactly what the present internals will withstand, choice of cam, head work and what size turbo to get. I think it can be done with some degree of reliability.

 

[matt167]

From what I hear if you open the ring gap, add a cam with one turbo you will be there. Of course horses cost money, how many do you want? Your best bet is to do loads of research to see exactly what the present internals will withstand, choice of cam, head work and what size turbo to get. I think it can be done with some degree of reliability.

cheap and dirty is buy a 200k mile engine, swap cam and springs/ lifters and send it

 

[curtis73]

I'm currently building an LQ9/ported LS6 and plan on running it with a van ECM and a flex fuel sensor. Should be 500hp without boost. Once I can find a reliable way of using the flex fuel sensor to control boost, I may add about 10 psi of turbo, but the problem is (from initial maths) I should be able to do 10psi on E85 and only about 2-3 psi on gasoline with my quench and compression ratio.

The number that keeps getting thrown around anecdotally for many of the LS truck engines is 750hp limit on stock internals. That is, of course, completely dependent on a bazillion factors. Some might explode at 450, others might go to 1200hp a few times. It's also dependent on what you intend as far as reliability - a drag racer making 10 passes before you rebuild it... or a driver that you want to use for 5000 miles a year?

 

[Tonz]

I'm currently building an LQ9/ported LS6 and plan on running it with a van ECM and a flex fuel sensor. Should be 500hp without boost. Once I can find a reliable way of using the flex fuel sensor to control boost, I may add about 10 psi of turbo, but the problem is (from initial maths) I should be able to do 10psi on E85 and only about 2-3 psi on gasoline with my quench and compression ratio.

The number that keeps getting thrown around anecdotally for many of the LS truck engines is 750hp limit on stock internals. That is, of course, completely dependent on a bazillion factors. Some might explode at 450, others might go to 1200hp a few times. It's also dependent on what you intend as far as reliability - a drag racer making 10 passes before you rebuild it... or a driver that you want to use for 5000 miles a year?

My goal's to make a weekend street car that'll still impress on the strip. So yeah id say geared more towards 5,000 miles a year instead of 10 passes down the quarter

 

[Tonz]

My goal's to make a weekend street car that'll still impress on the strip. So yeah id say geared more towards 5,000 miles a year instead of 10 passes down the quarter

Ok it just clicked in my head how much 5,000 miles a year actually is. It wont be seeing THAT much driving, probably nowhere close 😅, but still, would like it to last awhile