We're all at least a little jealous (ok.... A LOT!!!) and very happy for you Dennis. Can't go wrong with a car that nice, a legendary Z11 engine that's as close to a brand new one as possible, and such a great group of people behind it all. (Buyer, seller, and wives!)
I like the build plan, but have a couple questions / suggestions:
Normally for such a rare beast I'd say just leave it 100% stock, but considering the value of it and that you're already straying towards a street roller cam you sure don't want to risk it ever coming apart.
1. Are the Z11 rods different than regular 409 rods? They look a little beefier. Maybe have the beams polished to eliminate stress risers and some ARP bolts installed??
2. What about having the pistons lightened? I don't think I would want "max lightened" for it, but I bet a good bit of weight could be whittled away and them still be plenty strong. Maybe target around 750 grams or so?? Seems like a shame to do any milling on such rare pieces. It would be a worse shame for something to let go because they are so heavy.
3. You're probably going to do this one already, but for sake of mentioning:
Get the best lifters (probably Isky Red Zone with bushings instead of needle bearings), valvesprings, and pushrods that you can to compliment that camshaft.
4. No suggestion here just a question/observation. I noticed the balancer is weighted like a 454 or 400 small block. I never knew the Z11 was externally balanced. Did they have an externally balanced flywheel as well or were they just weighted on the front end of the crank?
5. Is there a Commandment - Thou Shalt NOT Covet Thy Friend's Z11 ?
I met with the gentleman that will be building this project for me and we discussed the build. I told him what my intentions were and we started from there. He has built several Z-11 and Z-11 components for many years. I asked specifically about the pistons and we will leave them original in every way. We are going, in his opinion, with a top of the line proven valve train assembly. The original two piece valves (original and currently in the heads) will be replaced with modern single piece units. The rods will be refurbished and new ARP rod bolts will be used or one's he considers better. According to Phil, the balancer is unique (at the time) to Z-11's and will be used as well. All the original assembly bolts are there and new. They will most likely be relegated to the "display only" duty in my home with new bolts used through-out. We also discussed a 4 / 7 swap for the cam, but is does change the way the motor will sound and with my intentions not to run it at more the 7000 RPM, we decided to keep the firing order original. (It will never see 5000 RPM, just kidding) I'm a little overwhelmed at the moment to think much beyond getting started. Most folks will say this is crazy to be driving this on cruise nights and local shows and I'm somewhat inclined to agree with them. At least with my plan, the Z-11 will be seen by those not able to have access to private collections and might understand what they are looking at. With all the components Phil has acquired over the many years, we could build this this motor at about 95% NOS, or near new, late 1962 GM parts. If I did that, I wouldn't drive it. Will know more as we move along !!