DIY Ported Lower Manifold

SouthArk370Z · 12-04-2016, 05:47 AM

If the walls of the head and the manifold match, then all you really need is the proper size gasket so that the transitions are smooth. When I was working on engines back in the '70-80s, we used RTV - run a small bead around the edges of the gasket while it is in place on the head or manifold, allow to set, and trim with an Exacto knife. Don't know if that will work on modern engines. Didn't have the too-big-gasket-hole problem on the exhaust side - they were nearly always too small and needed to be trimmed.

Back in The Good Old Days, you could get better flow with a good port-matching/relieving/polishing job. As you mentioned, the manufacturers are now doing a pretty good job of this at the factory, so gains will be small. Not worth the time and effort unless you track the car, IMNSHO.

12-04-2016, 05:47 AM	#1 (permalink)
SouthArk370Z Premium Member Join Date: Nov 2010 Location: South Arkansas Posts: 8,435 Drives: 2014 Challenger Rep Power: 324198	If the walls of the head and the manifold match, then all you really need is the proper size gasket so that the transitions are smooth. When I was working on engines back in the '70-80s, we used RTV - run a small bead around the edges of the gasket while it is in place on the head or manifold, allow to set, and trim with an Exacto knife. Don't know if that will work on modern engines. Didn't have the too-big-gasket-hole problem on the exhaust side - they were nearly always too small and needed to be trimmed. Back in The Good Old Days, you could get better flow with a good port-matching/relieving/polishing job. As you mentioned, the manufacturers are now doing a pretty good job of this at the factory, so gains will be small. Not worth the time and effort unless you track the car, IMNSHO. jrb55gh, TBatt and Ghostvette like this. __________________ Steering Lock Links - Search The370Z Bookmarklet - FSM @ NICOclub Mankind has progressed past the need for war but we haven't evolved that far. - NachoMahma

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