Nah. Any non B35 M30 head with an '80s casting is fine. M30 heads from the mid-late '70s cracked because of thermal reactor heat.
FYI, if you happen to reply to multiple comments in the future you can select only the portion you'd like to quote and hit "Reply". Makes it a lot easier than the extra effort you made.Don, your passive aggressive attempt at making me look ill-informed didn't really work, sorry.
1. Why did the heads in Europe crack even though they did not use thermal reactors?
There was not a high incidence of heads cracking in EU, in fact there were too few to become an issue to be considered a design flaw. The main reason for the head redesign was in direct correlation with the known heat issue created by the thermal reactors. The M30 head remained the same through the '70s until the redesign. Was there a known issue with cracking heads before the thermal reactors were put in service anywhere on earth? (Spoiler coming) The answer is no.
2. Of the 3 different intake port gaskets used on the big six engines, which one should you use to best match the 1970’s stub manifold port shape to the 1980’s head intake port shape knowing that “ the mid-late ‘70s Intake ports look radically different from the 1980’s intake port design?
The B34 gasket, of course. The difference in the L-Jet maniold and the B34 head is that the later head doesn't have the pronounced hump in the ceiling that the manifold has. If you are mating the two and you have any idea of what you're doing, you would port match the early manifold to the stock B34 gasket (head) shape. Radically different? Not really. I hope this wasn't supposed to be a hard question!
3. Why did AMADEO MARTÍ CARBONELL invent the Spanish head for sales to Europe using the M90 waterjacket design if thermal reactors were not used in Europe?
The AMC head's main market was the USA, and was an alternative to the dealer part number. Those heads sold like hot cakes in the "Thermal Aftermath", for no other reason than,.... Yeah, that darn thermal reactor issue. When you say "M90 waterjacket design", I think you meant to say "The updated cooling passage design", used in US in the M30B32 at the time, continuing through the run of the B34. The difference was bridging the passages in the head instead of the open passage like the M10.
I didn't see you debating why any '80s M30 head wouldnt work, as I said in my original response. Waiting.
If this is the case, why do 70% of existing e9’s have replacement heads? They have no thermal reactor or cat. Perhaps my figure is high.Nah. Any non B35 M30 head with an '80s casting is fine. M30 heads from the mid-late '70s cracked because of thermal reactor heat.
Yes your figure doesnt really reflect reality, but why are you stating that you aren't passive aggressive? Did someone call you that? Not here, not in this thread.If this is the case, why do 70% of existing e9’s have replacement heads? They have no thermal reactor or cat. Perhaps my figure is high.
I don’t consider myself passive aggressive. I am very technically curious and genuinely like to know why things break. I would love to run an original head if it isn’t going to crap out on me.
Nobody called me passive aggressive. You did say that @sfdon had a passive aggressive response and I wanted to forewarnyou that my question is driven by other motivations.Yes your figure doesnt really reflect reality, but why are you stating that you aren't passive aggressive? Did someone call you that? Not here, not in this thread.