Hey guys.
bear with me here, i've asked this question before but its been so long since i've done this.

Will a 91 Lesabre 3800 fit in my 93 Park avenue 3800? I know the intake manifold would have to be changed, but is there any differences between these engines that would keep me from swapping em?

I suspect my park avenue'* engine has weak compression. it has a wierd miss at idle that smoothes out with at higher rpms. This is because i roasted the motor till i heard metal clanking and since then, it hasn't been right. The miss disappeared for a few months, but now its back, and the engine feels weak, its worse towing a trailer.

The 91 has a low miles engine, and its quiet as can be. I figured to swap the engines, and i would have something like new on my PA.

Another thing i wanted to do. My PA'* engine had 385,000 kms on it. Is it worth it to do a rebuild? I was also thinking of boring it out, new pistons, rings, and doing the complete motor. I was thinking of a few mild upgrades to the motor to tune it a bit. Is there any benefit to this? Will gas mileage be worse after boring it out? I know I could swap in a series 2 motor, but i want a fuel miser and to be able to run reg gas.

Thanks, i'd appreciate any input.

Isn't the 91 the C motor and the 93 is an L27? I'm unsure of the differences in head or otherwise beyond them simply being different from teh exterior.