I never understand( I speak French) what does mean Crate?
Thanks to explain me

"Crate engine" is a common term we use that means the engine was bought assembled and ready to be installed in a vehicle.

Go search in the Dyno section of this forum for results using lq4/lq9 engines. Depending on how the heads/cam/intake all match up you could see north of 425-450 horsepower to the rear wheels which would be somewhere around 500+ horsepower at the crank.

With an lm7 heads/cam/intake you are limited to 350-375 horsepower to the rear wheels depending on how aggressive the setup is. Some guys have made more but they have been all out race setups with ridiculously high stall speeds.

In short, if you want 425 horsepower of streetable power you can do heads/cam/intake lq4/lq9. In order to get that out of an lm7 your going to have to look at forced induction such as a supercharger or turbocharger.

Thank you all
Lq9 408 stroker what thing about this beast?
Guessing if is comfortable for a daily driver truck,?
Does exist a limit hp range, 450 maybe is too high for the daily
I look also to build the engine with bare block, pistons etc but how it s hard?
This adventure don't afraid me, the only thing make me doubt is the wiring harness
All option interest me, just the turbocharger is not an option, I m not sure if the lpg system support that

I had a cammed LM7 in my truck for 130,000. Loved it, made great power, sounded nasty, and even got pretty good fuel economy. After it broke one rocker arm the motor was never the same and eventually croaked within 25,000 of the first one breaking. I just recently swapped it out for the LQ9 and holy shit what a huge improvement. Love it and wouldn't go any other route. It's much faster and puts down more power. I would highly consider the LQ9 swap.