Hey Guys and Gals. It has been a long time since I have been on here and a lot has happened in my life making my Jeep take the back seat! I moved in with my Girlfriend, graduated college with a mechanical engineering degree and started my big boy job just to name the highlights!
For some background, I had originally planned on putting an AMC 360 in my Jeep. I had the engine in the machine shop supposedly good to go until my phone rang one day saying the 360 was toast with a crack going from water jacket through head bolt hole through to the other water jacket. So my new search began. I came across an AMC 401 on craigslist only 2 hours away from me for what I consider a reasonable price for being in Ohio. I bought it and brought it home. Since then, I have been getting machine work done on it so I can start the process of putting the CJ back together. It is going to be backed with the TH400 trans and Dana 300 t-case with the AMC 20 rear axle with one piece conversion.
My main question is with my setup (to follow below) what is an appropriate compression ratio to be able to run pump gas (91 octane would ideally be the highest).
The engine has just been bored .030 over and I actually also have the cam as well. Here are the cam specs: Comp Cams custom grind with 262/218 .493 lift intake, 268/218 .456 lift exhaust 180 LSA +4. This poses another question. If you are reading this Shawn (and anyone else with an opinion), this is the same cam you spec'd out for my 360, since I already have it I was planning on using the same on the 401. Is this a bad idea or will it work out alright? I am still on a sorta kinda tight budget and don't really want to get a different cam... I know in the other thread about the cam selection for the 360 you had said with 9.5:1 pistons I may need 91 octane. Does this hold true for the 401?
These are the pistons I am looking at for the 401: http://www.summitracing.com/parts/wis-pt116a3
I believe they should give around a 9.85:1 compression ratio with a 27cc piston head volume and 58 cc head. My head is stock with the correct springs for the cam.
So to recap, and I appologise for the long post, will the above pistons work with the cam I have on pump gas (91 octane)? And will it be okay to use a cam spec'd for the 360 in the 401? I believe dimensionally the 360 cam will fit the 401.
Thanks everyone! I really appreciate it! If you have any questions please let me know!