not sure where this is going but measuring on top of the motor on the 350 and 500 might not get any useful information. I believe the 500 engine may sit higher than the 350. I m assuming this also because most bulged hood are that way for a reason. did anyone just measure the hood along the sides from from to back ? again, measuring over the bulge would not give a fair comparison .

 

Headlights are 2 inches forward on the 500, so the hood would also be.
I can measure later if you have 350 measurements

 

See above; we measured the best we could. The shapes of the engines should have negligible impacts on the numbers. It's pretty much common knowledge by now that the front of the IS500 is two inches or so longer than the front of any other IS model. All the other dimensions are the same. So, even without measuring, it would be pretty bold to assume the hoods would be interchangeable.

 

At this point, we did what we could to warn others! (if they ever try to swap the hoods)

 

Also coming from a IS350 to IS500 owner, they are not the same length wise. My old TOMS front lip did not fit onto the IS500. It was short by about 2 inches. But hey if you guys are determined, so be it and more power to you. It'll be interested to see how people will deal with the "overbite" lol