Michael Harrington said

4spdragtop that is a great looking 273.​

The oOffy and probably the Edelbrock dual quad manifolds were specifically made for the 273 only. When the 318 came along it worked on those because the heads were the same. But no one tooled up and made a low profile under hood dual quad for the LA340 when it came out. Thats a shame. A dual quad airgap for the 340/360 heads would be awesome. I passed on the Modman. With its dual quad top, it looks wonderful. But really, it's a cavernous vast wide-open plenum manifold best suited as a blower manifold. Bolting on the dual 4 top looks great but from what I read not good on a moderate performing street engine.

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33IMP said

I'm not real familiar with small blocks.
Are those port pictures right side up, or upside down?
in other words, are the 340/360 ports taller than 273/318, and slightly wider??
I have a tm7 440 manifold that has had a slug of aluminum added to the top of the port, to work on a max wedge head. Top of the port with added material is fine, bottom of the port, the manifold is razor thin.

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