[ROCKLOBSTER]

You can still get many of these engines thru GM’s Performance Catalog.

You can also get any level of performance "crate" engine from Summit, Jegs, Mr Gasket etc.

[Elderberry]

My son's 75 454 Vette has a crate engine in it.

My son was in Nuclear Power School when the orig engine threw its timing chain.

He decided to put a crate engine in it and had a shop do the work that everyone said did good work.

Shortly afterward he noticed a vibration he hadn't felt before. He graduated and got assigned to a sub in Guam.

We hauled the car to my home and I took a look at it. The 454 is either internally or externally balanced.

Turns out the orig engine was internally balanced. The shop replaced it with an externally balanced crate engine, BUT reused the original harmonic balancer and flex plate.

I replaced those for the proper ones and life was good.