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vlad01 wrote: ↑Tue Jan 02, 2024 7:24 pm Yeah I've done this tuning with a decently large cam on a 355, the COME manifold was a step backward in every way compared to the banana, even though logic said it should have performed better, at least at the top end. But it gained nothing there and lost everywhere else significantly.

Iirc, it was about 235@ 50 on the duration, somewhere mid to high 500 lift and 10 ish odd comp. It made the same power as Gareth's ecotec with arguably a lot more mods, but on a smaller 228@ cam and 540 lift cam and at lower rpm too. But interestingly the eco ran banana manifold and good heads, alloy ones with extensive re-work done here locally (as cast they were pretty bad, lots of mistakes). Both made around the 210 rwKw, the v8 was at I think 5600 rpm the eco was at 5000 rpm. Torque was higher on the eco iirc hence the same sort of power but at a lower rpm. The comp was crazy high though on e85 but not anywhere enough to account for the difference in nearly 2L and making it at a lower rpm and a smaller cam.

Also it's worth pointing out that the holden 8 has a notably larger cam per specific output than most engines used in our cars, which tells me that the heads are most likely the issue. It's also odd that the intake lobe is larger than the exhaust which tells me there could have been some band aiding done to try to improve some deficiencies.