426 Hemi Intake Manifold Instalation

[HEMI RR]

I am in the process of switching from a single Holley to a original intake and dual carters. When I removed the single intake I was happy to see a heat shield was attached because I needed one. Also, there was another surprise. I noticed the intake gaskets nicely stuck to the intake but there was another set on the block with a thin piece of rigid plastic that was between them. The car ran great so it must of been sealed but what gives? The engine had a total rebuild before I bought it about 5 years ago.

 

[Fran Blacker]

Any pictures ? How thick were gaskets and plastic. Maybe the block and or heads were cut?

 

[pnora]

That is a big gap. Thats why a single gasket is not enough and most use a large bead of RTV to seal it up. Someone had a plan B with two gaskets and the plastic. It would be nice to see some photos.

 

[HEMI RR]

That is what i was thinking but never saw it done that way. Pictures coming.

 

[HEMI RR]

Here are the pictures. I guess I will order another set. The thickness seems to be stock size. Also, I have to paint the intake bolts. Were washers used at the factory? The intake I removed has washers and would be a pain to paint so are they needed?

 

[pnora]

My Bad. I was thinking end gaskets. That's odd on the side gaskets. Look close for a name or number on them.

 

[Fran Blacker]

Can you measure how thick the gaskets are, don't bother about plastic or ends. Did he use silicon to glue to one of the gasket on each side? He might have thought easier to remove intake?

 

[AR67GTX]

I second trying to get a measurement on gasket thickness and if you can find a small overhang area that wasn’t compressed, also that thickness. There’s a wide variety of intake gasket thicknesses available and figuring out what you need is a mystery - but if the old ones seemed to seal good and the bolts holes seemed well aligned with the block holes, then knowing the thickness of the old ones is a good starting place.

 

[HEMI RR]

I end up ordering a double thickness gasket . 120". Leaving out the washers too. I checked many pictures of 426 hemi engines and it appears that there are no washers on the manifold bolts.

 

[AR67GTX]

My intake bolts also had small captured washers and the repro bolt set (AMK) from Mancini had captured washers too. Are you talking about the small captured washer or an additional one? I actually added a second, small, black washer under my bolts in hopes it would minimize chipping paint on the intake and help stabilize torque stress. Probably a bit of OCD.

You’re right that the bolts were originally painted which was obviously after the engine was assembled. I left mine unpainted as I knew that the numerous times the manifold would need to be re-torqued would scar the paint up on the washers and maybe allen-head bolt tops and I didn’t want to be trying to touch them up. I’ve probably retorqued mine at least a dozen times and it probably needs another go around now. But yeah, original is painted.

Reproduction set for 66. I had to send Mancini a picture as I was missing one stud they had to send me.

 

[HEMI RR]

Thanks for the info.

 

[Fran Blacker]

@AR67GTX did the Mancini kit tell you where the studs go? Have a 68 intake on my car now go to put the 66 manifold.

 

[AR67GTX]

Fran, no it didn’t but I believe I found something else that did. I’ll look at my papers and see what I have. I fit tested my manifold several (many) times with shims to try to get an idea of the best thickness to use and I trial tested the various lengths to confirm their location. The bolt boss heights and various brackets on the right side kind of make it apparent.

 

[AR67GTX]

This is basically what I used to reinstall mine, along with the FSM and advice from the forum. It doesn’t say where the various length bolts and studs go but the drawing has circled in red, where the studs go. Looking at the height of the manifold bolt bosses, it was pretty clear where the short ones went and where the longer ones went. It all worked out fine, the only one that seemed slightly off was the longest stud that I put on the left front with the plug wire holder. It’s probably about 3/16-1/4” longer than necessary but works fine.

Curious Fran - what’s different between a 66 and 68 intake?

 

[Fran Blacker]

Thanks. Manifold difference, no pentastar on 66 and I think 67. Above the paint stick you can see just the p/n's no Pentastar. Was trying to see if the orange matched the intake it's original orange.

 

[AR67GTX]

Guess I have an early one then - thanks. Most of my engine is a 68 or 69.

 

[Dragon Slayer]

Hemi intake bolts do have capture washers. How your intake fits depends on whether heads/block milled or intake. With good port alignment we glue the intake gasket to the head, but use think white grease on intake side. Allows easy removal on intake.

Depending on gap at china wall, you can use gasket and rtv, or just rtv. Torque in sequence, and retorque several times after waiting a period. I have torqued the end bolts above 48inlbs, closer to the 72, NO bolts in the china wall like the first 66 cars had.