Did a quick search and didn't find any info.

I received the Clearwater head. The old head was already off by the previous owner. I was packing the old head to send back as a core. I saw AMC on the old head. Now, is this an aftermarket head or is it the original head? Is AMC the same company that makes the Isuzu 2.6 head? Anyone knows?

Now I just acquired a cheap '87 Raider auto with engine problem. Really want to do turbo on this one. I've read the bible many times. Is this doable for a person who had rebuilt engine twice? Do I really need the whole engine replacement or can I get away with just the top turbo swap? Thanks for any tips.

AMC is an aftermarket head caster, and I think they make the clearwater head. It's a good head.

You really need to lower the compression with Starion pistons or similar (8.25:1 or lower - stock is 7.0:1 for Starquest pistons, 8.7:1 for carb 2.6), and I really like the piston squirters, which can be retrofitted into most 2.6 blocks. The rest of the motor is mostly ok. Have to use the Monty oil pump and pan, though. The actual work is simple, and I think you can do it. It's all worked out now....

Hmm...

That's what I think. I might just keep that AMC head and tear down the raider's to send in as core. The AMC head was popular in the Isuzu forum, and I got that on my pickup. But I really want to do the turbo as well. Thanks.

Does it have jet valves?

Sorry, I don't even know what jet valve looks like.

definitely use the new head from clearwater... who knows why the PO had the head off.

Jet valves are very small extra intake valves that feed a nozzle in the combustion chamber. They are fed a lean mix from the carb thru the intake mani to the skinny passages under the mani flange, and from there to the passage under the jet valve head. The intake rocker has an ear with a lash adjustment screw that opens the jet valve at the same time as the intake valve. The nozzle in the combustion chamber sends the jet valve very lean charge into the incoming main intake air/fuel mixture, and makes the whole mess swirl around the chamber. This is supposed to make for cleaner combustion (higher probability of firing a leaner mix). The skinny little jet valves will eventually break off the valve head, letting the stem, spring, and retainer tour the valve train. In short, the answer to the question is that a jet vavle is a problem waiting to happen. Caravan 2.6 heads minus the jet valve assy. is what we get from clearwater, and you usually get manual lash adjusters with them, unless you order it with hydraulics, since that's what caravans came with....

the jet valve is the small valve near the spark plug hole.
Right next to the big exhaust valve.

Big valve is the intake....

Thanks for the picture. It really helped.

The AMC head doesn't have the jet valve.