Probably a stupid question. Will an LS swap damage the long term value. I know these cars are not rare, but they are becoming more desirable, and values are increasing. It's a very clean 91 Z28 hardtop with the 350 TPI, does need a repaint. Im not looking for max power or to race the car. Im looking for the reliability and ease of modding the LS. I love the sound of an LS with a cam. Car would otherwise remain stock.

 

Only if it's a rare, limited-production model (such as a Turbo T/A, Official Pace Car, etc.). Otherwise, no.

 

Or, if it's a time capsule; like, less than 10k miles, always garaged, clean, no wear on the interior, no oil leaks, no rust, etc.

These cars simply don't have "that kind" of "value" except in a very few very rare circumstances. One that needs a repaint is not likely to be in any of those.

If I were in your shoes, I'd be looking for a LQ9 or LS2 pullout, with wiring & ECM.

 

If a 3rd gen is a low-mileage, pristine survivor, I usually suggest leaving it alone; they're only original once. If the car in question doesn't meet that criteria, do as you wish.

My only caveat to potential modifications is to be sure you have a well-thought-out plan, and plenty of $$$ (usually about double what you think it will cost) to carry it through properly. Otherwise, regardless of the condition the car was in before the swap, if it never gets finished or is hacked up due to corner-cutting, the car's value will be a moot point.

Whatever you decide, GL.