(03-08-2020 )Brock Wrote:  I'm not hung up on anything, I dont care that you went through a turbo and a head..... completely normal with your torque loads. Your preaching to the choir with me man, I live in Grande Praire Ab and have always hauled 100,000 to 160,000lbs...... always, so I know what your talking about.

I was considering going to a 16:1 on my c15 and throwing the 18:1 away but decided to run a ISX871 instead.

What kind of big power are you talking? If your going around 600 or 625 then I would see no need to lower compression as the ISX engines dont really have head pressure issues that I'm aware of and the bigger CPL engines were built for 600 anyways.

As far as the Variable turbo, once again, talk to Hammer and ask him how the Blue Ox exhaust brake he has has been holding up, last I spoke to him he said the thing hits hard, not quite as well as his VG but still real good..... it has been a bit since we spoke though.

Now all of this is just my opinion, its apparent that you have a different one and seem to have already made up your mind. I have zero working knowledge of the internals of the 570 or even what their compression ratios are. If you are wanting real high horsepower then there are s multitude of things you can do, lower your compression ratio, big turbo, new cam etc aussie spec the engine basically.

(03-08-2020 )Signature620 Wrote:  It's certainly not impossible to build an 870 with 570 pistons but the end result would not justify the headaches and costs. If you bought an 870 o/haul kit and a set of 570 pistons, you'll spend a fair bit more and have 6 870 piston kits you'll never need. If you buy a 570 o/haul kit, half the gaskets won't fit. The 570 pistons will also require a different part number injector - Which you won't have any cores for. They may also require a different injector cam. On top of that, the new injectors would need a completely different set of maps in the ECM to run correctly. By the time you're done, you could've just rebuilt it as it is and gotten the power increased and/or VG removed.

As Brock said, 870s don't really suffer from excessive cylinder pressure. As with any ISX - It's all in the injection timing & liner protrusion.

(03-08-2020 )Unilevers Wrote:  i have physically done this conversion, and it was 100% not worth it. The cams are the same if you have a big CPL 870, but thats about it. The injectors, turbo, manifold, IFSM, ecm, etc etc are all different. you have to piece together a kit manually.

In the end just buy a set of IPD 870 steel liners and pistons, decide what your turbo setup and torque loads and desired HP are going to be, and have it built and tuned properly. 870's can handle high power fairly well.