Thanks- you saved me the trouble!
And yeah, the dual plug engine certainly had some growing pains, but it was a great idea. I'm sorry you're giving up on it. What did what's his name say about the heads?
He had some Covid or vaccine related heart issues (I was never clear), then (like so very many people in this hobby) just seemed to lose interest. He's tired all the time from the myocarditis, it's not his day gig, and I'm not standing in front of him. He does a lot of rally-car work and that pays better than the VW stuff, I think.
The heads had issues unrelated to detonation related damage, and fixing them was going to mean doing a bunch of work on them, enough so that it was a question if we should proceed or not. I approved the work, but he must have just run out of steam.
I sent a "hey, do you want to do this or not?" email, and got a "let me think about it" reply. That was months ago.
He flaked, for sure. I'm out the freight, but the engine never worked as well as it might have with better heads.
How to get that done is an open question. Nobody wants to undertake an experiment. If this were a T4, Hoffmann Engineering would ship me a set of head already done and ready to go in a month. Alas, this is not a T4.
... which, were I to do a twin-plug engine I would recommend doing. A 4" T4 is routine, the bore spacing is set up for it, and there are heads and headers that would work perfectly. 20 years ago, Raby was making 200 hp with crushing torque with Hoffmann heads on a 4" bore, twin plugs, and an 86b. He went on to make easier, more reliable power with smaller engines and less exotic setups, but his ways became much more secretive. He stopped leaving breadcrumbs to follow.