Renix head?

[mattwheels]

I apologize if this has been asked before but I've searched and searched with no luck.

So I have an 89 Comanche renix engine currently pulled out, and a 91 Cherokee that I'm swapping everything thing from into the Manche. I'm wanting to start gathering pieces for my future stroker plan and thats with future future plans of Boost.

My question is Because the CC of the Renix heads are a bit bigger, 10-15cc, can a Renix head be used on a HO block in this application? Advantages? or problems I might run into? If it matters I am using the 91 Harness. My Thoughts were if I used the Renix heads I could lower my CR in preparation for added Boost.

[DaemonForce]

The block isn't the high output part of the design. I have a 2686 head from an 89 block and I see little design difference in this block and every other 4L. The only thing that appears to change are the boss mounts and it seems poor freeze plugs.

The 2686 head is milled in such a way that the angle for injectors is choked up really high. From what I understand the 2nd gen intake doesn't quite line up with this so it's either a no go or a mod project with no appreciable gain. I've been over this before when trying to piece together a new blueprint for the 4L with updated components. I'll be using the Renix harness but not the head or manifolds. I'm remachining a high output 7120 head and whenever I find a 00' intake I'll bolt that up to it. Depending on what you're trying to do, I might suggest the same.

[Cheromaniac]

My question is Because the CC of the Renix heads are a bit bigger, 10-15cc

The Renix head has the same 55-58cc chambers as the HO head but the intake ports are lower so the HP output is reduced. You're thinking of the 258 heads which have 64-67cc chambers and they're definitely no use to you.
Since you'll be using the '91 ECU & harness, I suggest you also use the '91 head/intake manifold/throttle body/exhaust manifold. You could even use a '99+ intake manifold to gain a little more midrange torque and slightly better gas mileage.

[cruiser54]

Just an FYI. installing an HO head into a Renix equipped Jeep is easy if you have minimal porting skills.

I'm on my 3rd one. Using the Renix gasket, match port the intake ports on the head to that gasket and also the intake manifold to the gasket. I also do the exhaust ports on the head.

[mattwheels]

Yeah makes sense I forgot about the exhaust not being able to line up. I'm trying to aim for 8ish:1 CR with minimal quench like .04-.05, would that even be possible on a 4.6 or 4.7? imagining 30cc pistons are a must.

as for the renix block I already have the whole engine bay bare and getting ready for the 91 engine, hopefully it'll last long enough for me to start my stroker build.

[cruiser54]

The exhaust lines up fine.