« Reply #27 on: August 07, 2019, 12:10:49 AM »
These tiny Edelbrock intake ports definitely can’t support very much power. They may be good for a low RPM 360 or 390 motor but not a high RPM performance motor. Without any mods I don’t know how much power they can support but I would guess 400hp is probably not obtainable with any cylinder head. In fact, maybe 300 hp is more realistic. Someone else who has more experience with this manifold would know more about this.
If you decide to port match the intake to your gaskets or head port sizes be aware you need to ensure the intake runner cross section (further up inside the manifold) is similar size to your port opening size. In other words you don’t want a small runner leading to a larger port opening. This would accomplish nothing, the manifold would still be the bottleneck.
But this still doesn’t explain your vacuum leak.
I suggest placing a straight edge on the manifold to look for warpage or low spots possibly caused my aggressive gasket scraping or a power gasket scraper.
« Last Edit: August 07, 2019, 01:51:06 AM by 338Raptor »
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