Zr1 vs gt500
 

Why does the gt500 make 760hp with 5.2 litre and 12 lbs boost and the zr1 makes 760hp with 6.2 litre and 14 pounds boost? sounds like mustang is doing more with less!!

Overhead cams and 4 valves per cylinder. Also, GM doesn’t really push the envelope. They probably left plenty of power on the table.

I wouldn't say doing more with less. The mustang makes peak power at 7300 rpm vs 6400 rpm on the Corvette and makes 100 less peak torques. And more importantly the Corvette weighs about 700 lbs less.

Yes I just meant less cubes and less boost equals same power.

The GT500 has a DOHC engine (as Ford has used in the Mustang for decades). The Vette has a pushrod engine (as Chevrolet has used for decades). The cubes may be more for the Vette, but put side by side, the DOHC engine is much larger, whereas the pushrod is very compact.

Horsepower is just an empirical derivation based on torque and rpm. There is a direct relationship between rpm and horsepower.

Boost is not always indicative of true power but it is a measurement of restrictions so the 4 valve head/intake has less restrictions than the 2 valve head/intake. The smaller 5.2 DOHC is more the equal to cubic inches of the 2 valve 6.2 motor setup so things are more equal than not here so you can't really compare the engine sizes.

Anyone have any idea about the weight of each motor. To me that would be a better comparison vs displacement.

Not sure of exact numbers, but I believe they are within 10 - 15 lbs of each other.

it looks like the shipping weight on the LT5 crate engine is 619 lbs so its in car weight is probably a few lbs less.

This is simple, the TVS2650 on the GT500 motor is a way better/more efficient blower than the small POS blower GM burdened the LT4 with. LT5 which also uses the TVS2650 is a better comparison to the GT500 motor.

OP did ask the question about the LT5....

Educate yourself

You are correct. For some reason I was reading ZL1 instead of ZR1. My bad.

Pretty sure the ZR1 makes noticeably more torque than the GT500 by close to 100 lb-ft if I remember correctly. Also what compression are both motors running? That would make a noticeable difference.

GM typically sets up their motors to have a broader and more linear powerband compared to the Coyote based motors even though I'm sure the GT500 motor is pretty strong most everywhere. Just like with an LSx the GEN5 motors personality is easily manipulated by a cam swap.