Maryland Stang
Active Member
I guess it could be said that you can gasket match both the intake and heads to the same gasket before hand but... It is super critical at that point that you make sure everything lines up. The heads, gaskets and intake, perfectly upon assembly. Since you've machined all of the ports to a universal size there is probably very little room for error in the port alignments. But due to the way FI manifolds are designed you're going to need an inspection scope to do it.
The reason you can't just bolt it down and go with gasket matching is simple. Although all of the metal parts involved are designed to the same specs there will always be small differences due to things like core shift and manufacturing tolerances. No 2 blocks, heads or intakes are exactly the same. It's the same reason everybody here screams that you must check clearances when you put a new cam in. Intake runners are no different. The alignments vary from engine to engine.
There is also a certain amount of play when you bolt the intake down. There are no alignment dowels for the intake like there are for the heads. The manifold can rock asmall amount from side to side and forward and backward. Add in the differences in intake gasket thicknesses and you can easily imagine where the ports probably won't even come close to lining up perfectly when you bolt that intake down.
Even with an inspection scope the issues aren't over. You may need to try a different gasket to raise or drop the intake a bit. You may need to mill the intake. You may find that the block is a little off and one head is a little out of line. At that point you'd be screwed into doing a proper port alignment.
The alternative is just to make sure the intake ports are smaller than the head ports. That way unless there is a gross misalignment you know that there won't be any head port material hanging down into the flow of air. You also want to make sure you use a larger gasket port too so even if it moves around during the bolt down it won't block the ports.
The reason you can't just bolt it down and go with gasket matching is simple. Although all of the metal parts involved are designed to the same specs there will always be small differences due to things like core shift and manufacturing tolerances. No 2 blocks, heads or intakes are exactly the same. It's the same reason everybody here screams that you must check clearances when you put a new cam in. Intake runners are no different. The alignments vary from engine to engine.
There is also a certain amount of play when you bolt the intake down. There are no alignment dowels for the intake like there are for the heads. The manifold can rock asmall amount from side to side and forward and backward. Add in the differences in intake gasket thicknesses and you can easily imagine where the ports probably won't even come close to lining up perfectly when you bolt that intake down.
Even with an inspection scope the issues aren't over. You may need to try a different gasket to raise or drop the intake a bit. You may need to mill the intake. You may find that the block is a little off and one head is a little out of line. At that point you'd be screwed into doing a proper port alignment.
The alternative is just to make sure the intake ports are smaller than the head ports. That way unless there is a gross misalignment you know that there won't be any head port material hanging down into the flow of air. You also want to make sure you use a larger gasket port too so even if it moves around during the bolt down it won't block the ports.
