P-400 engine replacement h1
 

Hi everyone, I've been researching engine swap solutions for my 1999 h1. I had a main bearing issue and had the engine overhauled, replacing everything. When I got my truck back it was leaking from every gasket and was pushing coolant out. Turns out the block was cracked, and not in the typical #8 cylinder. I think from replacing the liners.

I'm looking into getting the p-400 engine. Leroydiesel.com had the best price of the 6 places I contacted. Anyone has the p-400 installed . And are there any issues? I wanted to get a bit more power. I'm budgeting around $10,000.
Any help would be highly appreciated .

I don't think there is any major issues with the P400, the lower girdle is different, you'll need to modify the flywheel inspection cover since the shape is different.

I was in the same boat and I wound up getting a new Optimizer instead, only because I couldn't get a warranty on the P400 from anyone who was selling them [for whatever reason AM General/hummer service centers can't get a P400, it exists as a P/N but AM General isn't filling inventory for dealers].

You must be on the hml. They pop a lot of popcorn!!!! When doing a p400 there is a good amount of things that should be replaced/ repaired. You should have a shop that knows hummers work on your truck. That could have saved you all the time and money that was waisted on the previous repair. I could have almost diagnoised that over the phone. There are few folks that really know hummers and even less that sell quality work and products.Check out Big Dog Offroad in golden CO. Where are you located at ?

A basic P400 swap is about $14k. Power mods are more depending on what you want to do. We do P400's all the time and we are an AMG dealer and we are able to supply and install the engine and related parts.

Just as a follow up on this thread: the P400 has been discontinued by AMGeneral. We bought the very last one and it's sitting on our shelf on a pallet ready to go into someone's Hummer. ;-)