Which Cat 3406 should I start with for maximum HP

Correct on the 15.8L's

Hard to say the cost difference, depends on the engine you build and if you do a build and you plan on replacing injectors and cam no matter what then the cost will pretty well be the same no matter what engine you're building as long as you don't have to replace the crank. I'd say the 15.8 cylinder kits may be a little more money than a 14.6 but I doubt a lot if any.

If your doing a build on an MBN than your definitely replacing cylinder kits, injectors and cam to make it a true 6NZ.

 

More than likely that engine was built with aluminum pistons. Which means you're gonna be very limited on the power without risking damaging the pistons. Basically you bought one of the worst 3406E's to build big power with. Without rebuilding the engine and putting in different cam and steel top pistons your not making over 500hp safely. Than if you do that you run the risk of the block cracking around 800hp or more. I've heard you can use, I believe B model oil pump plate whcih is suppose to be bigger than the 5EK's and that will act as a girdle for the bottom. Weather it will help the block from cracking I'm not too sure.

 

4CK is PEEC...look at another 1K to convert to mechanical, or just walk away.

 

According to CAT it started life as a 435 Hp engine. It has been updated with a LOW NOX Software file, but not a 455 Hp file. You are probably seeing the MAX Hp rating available with this engines combination of parts by CATERPILLAR that is also listed on the engine tag. It isn't a bad engine, but you'll have to change a number of parts to achieve the Hp you're looking for.

 

pistons, cam and probably injectors.