5.3L LM7 Swap into OBS

[0xDEADBEEF]

Out of curiosity, what does it take to get a stock 5.3 to 400 lb/ft of torque? I'm not doubting that LS motors are the way forward. I'm a 350 fan simply because they're cheap. Also, I'm hopeful that my stock-headed, 4.000" bore 350 with a cam and springs is around 400hp once it's tuned. Everything I've read says yes.

At the crank it can be done with just a cam and valve springs, but people will still complain about where the peak is.

Edit to add headers and supporting mods, blah blah blah.

 

[L31MaxExpress]

Out of curiosity, what does it take to get a stock 5.3 to 400 lb/ft of torque? I'm not doubting that LS motors are the way forward. I'm a 350 fan simply because they're cheap. Also, I'm hopeful that my stock-headed, 4.000" bore 350 with a cam and springs is around 400hp once it's tuned. Everything I've read says yes.

A cam and lots of RPM. The L31 with the 196/206 marine cam makes 400 ft/lbs almost off-idle.

 

[L31MaxExpress]

Out of curiosity, what does it take to get a stock 5.3 to 400 lb/ft of torque? I'm not doubting that LS motors are the way forward. I'm a 350 fan simply because they're cheap. Also, I'm hopeful that my stock-headed, 4.000" bore 350 with a cam and springs is around 400hp once it's tuned. Everything I've read says yes.

LS is old news, the LTs run circles around them. Higher compression and better headflow with direct injection.

 

[L31MaxExpress]

Then again for a small block my little 383 is still in the fight making power. Its pulling 500-510 hp worth of airflow and requiring equal fuel to hit the 12.6:1 afr target at a modest rpm. Even with a ported L31 truck intake it wraps effortlessly up to 6,200. Peak airflow is around 5,700 which is where it should make peak power. Spins the heavy stock diameter 4L80E converter up effortlessly. With the 2,800 converter and 5.13s its going to rip.

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[Wh4t3v3rs]

LS is old news, the LTs run circles around them. Higher compression and better headflow with direct injection.

I can appreciate the LT motor, absolutely! $10k for the basic 600hp and $25k for the 700÷hp, ill let ya keep em! The time it would take a normal person to save that kind of money, I can have a couple seasons of racing in..... I'll keep building my "old news" bolt a couple turbos on, have $3k in it and have double the horsepower. Say what you will, but the LS platform is rock solid and holds its own!!!!

 

[Wh4t3v3rs]

But on a positive note, I hope the LT motors become as available and affordable as the LS!!!! I would love to build a turbocharged LT motor!!!!

 

[0xDEADBEEF]

Even the LT motors are old news (8 years?), it wouldn't surprise me if the LT2 was the last one.

 

[Wh4t3v3rs]

Even the LT motors are old news (8 years?), it wouldn't surprise me if the LT2 was the last one.

The LT6 is the newest one in the new Z06 Corvette.

 

[0xDEADBEEF]

The LT6 is the newest one in the new Z06 Corvette.

Yeah, but it is LT in name only.

 

[stutaeng]

I'm starting to see the Gen V (LT-series) engines on the streets now around here. 5.3 complete with 8 speed, wiring, etc. I think are starting from $2800/low $3000s and up. That's actually not even much more for what the Gen III/IV are going for with a 4 or 6 speed.

On those comparisons from Richard Holdener, it seems that the LT engines "don't leave much on the table" from a performance perspective, compared to the previous generations. So maybe paying a little more up front won't require a lot more of mods down the road. I don't know much of the LT engines, so I'm just guessing here. Then there's the DOD/AFM things to deal with...?