Install Blue Thunder intake

[Barry_R]

I spend an inoordinate amount of time fitting intakes. Seems to be my Achille's heel.

I will use a pair of non-embossed gaskets - like the Mr. Gasket 202A, and set the intake in place dry on them using an empty distributor housing as a locating/positioning dowel. I will then square the end seal "China walls" so they are level side to side - usually somewhere around .100-.150".

Once located and level I will take feeler guages and check the angle fit by stabbing all four corners upper and lower - you end up with eight measurements - front left upper, front left lower, etc. The desired is that you have no more room than .010 at any corner. I write them on the intake at each point with a Sharpie.

Now I look at port alignment and bolt hole alignment using a small flashlight and dental mirrors. Here you want bolt holes as close to centered as you can get them, and ports with a smooth transition - especially at the top and "long" side. Also look at the valve cover rail alignment - if its too high or low it'll cause problems. Once again I mark things up with a Sharpie so I can keep track.

Pushrod holes come next. While mocked up you can usually test fit pushrods - unless things are waaaaay out of trim. With pushrods in place and rockers clicked down you can roll through a couple turns to see if and where the pushrods hit on the passages. On milder motors things here are usually fine. Some of my stuff requires drastic moves and changes. Best to know first, before we start cutting. Sharpie......

Some guys get lucky and things are great right out of the box. Never seems to happen for me, and I end up trimming the intake to get close to the right angle, height and port alignment. Often its really a best shot deal where you can't get it dead perfect without multiple machinings - but close enough is good enough for the vast majority of builds. Your machinist should be able to interpret all the Sharpie markings after he gets done laughing at them - FE intake faces are a flat 90 degrees to the deck so its easy math to lower the intake - or double/thicker gaskets can raise it if required. Bolt holes can be opened up as needed - Dove intakes often require a couple opened to just get bolts started - better again to test fit fasteners and fix before installing.

I have been using High Tack spray adhesive to glue gaskets to the heads, a "coat of paint" thin layer of silicone between the gasket and the intake, and a silicone bead front and back. I prefer the Motorcraft gray silicone that is designed for 6.5/7.3 diesel engines - highly oil resistant, and sets up very firm - almost plastic like. Comes in a caulk tube from the Ford dealer.

Once everything is installed be sure to pull the distributor out and be certain that silicone has not pushed into the distributor hole - its tough to remove once dry.