I can also supply the more powerful direct fuel injected LT family of engines.

These engines make more power and get better fuel economy than the old engines.

They have nothing in common with a Gen 4 engine, a few bolts is all.
It is a new design and very much superior in every way.
The GM engineers pulled out almost all the tricks learned since 1955 when it all first started.
Drag racing, NASCAR racing all had a hand in providing knowledge GM being incorporated into its design.
Both strength and power output are built right in

But in 2021 most people swapping engines are still afraid of it.
It is understandable given the complex variable camshaft adjusting system, the cylinder cancellation phasing and of cause 2900PSI direct fuel injection.
How are you going to "hop it up?
The answer, GM already built you an awesome engine, just put long tube headers on it and noisy mufflers.
This engine in any street car in NZ will get you a speeding ticket of blow of most LS engine swapped cars, and do it with better fuel economy.
It is engine design like this that has kept V8 engine under the hood of American car in spite of those people trying to put an engine to gasoline cars.
You should be thanking GM for all they have done for you these 66 years.

An LS6 engine with 4L60E trans will sell on eBay for say $10,000NZ.

An LY6 with 6L80E trans maybe $7500NZ.

An L92 with 6L80E $9100NZ 

A Gen 5 6.2L L86 with 8L80E for $10,000NZ
 or with 10L80E $11,300NZ

5.3L  L83 with 6L80E $6500NZ

It is early to be finding the improved 2020 LT2 engines, but I do see a few for $28,000NZ

And LT4 $15-25K NZ.

Click on the following video for a better understanding of these great engines.