360 Intake manifold bolt misfit

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wafastr

wafastr

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My 360 was recently rebuilt by a local experienced and respected builder. It has not been installed into the '70 Dart yet. The intake manifold bolts I provided him are 1 1/8" long, not knowing if that is what I needed or not. The intake is a Performer RPM with Edelbrock heads and gaskets. I noticed that some other advertised intake bolts are longer, so I took one of mine out to check and found it only penetrated the head by about 3-4 threads before it bottomed out on the manifold. It doesn't seem deep enough to me, so I asked him about it and he doesn't think it is a problem since it is not a moving part and seems to seal correctly. I tried some Edelbrock bolts that are longer and they only thread in by hand about the same distance until they interfere with the bottom edge of each intake bolt hole, visibly a bit off center, making it too difficult to thread by hand. This is probably due to my block being surfaced at some point which lowered the heads, causing a few thousandths inch misalignment and interference. I don't want to force a bolt that won't go in finger tight unless I know it is correct. Maybe the stock cast iron intake has a thinner bolt flange area than the Edelbrock, and a 1 1/8" bolt works for that combo. I have heard of some people enlarging the bolt holes to make it fit, but I don't want to do that. SO- I put it out to FABO members and experts for discussion and advice. Thanks in advance!
 
I believe you should have 1.5 X bolt dia. for proper thread engagement length. 65'
 
That's not enough thread engagement.
 
You might need to get the manifold shaved a little on each surface to get it to fit properly but there are many unanswered questions.
 
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How well do the bolts go in without the intake manifold on top?
 
Are there clearance holes in the intake for the pins that hold the cork gaskets in the intake valley???? If not, you either have to remove the pins or drill clearance holes in the intake so it will seat properly... I had the same issue recently with an LD4B on a 318....

Bolt length should be 1 1/2"....

Have the bolt holes been chased with a tap to be sure the threads are clean and true????
 
Do the bolt holes line up with no intake gaskets in place? If so you may need to have the surfaces machined. And like krazykuda said, look for alignment pins in the front and back "china walls".
 
Look at the intake flange of the head, tell me how many threads you see.

I just re read and caught the eddy head part.

I'm sure you can figure it out, don't let a bolt outsmart you.
 
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I use these (on everything) 1 1/2" with small washers. I like em cuza the small head on them / no interference on the intake runners and they're nice loooking.

intake bolts.JPG


20171221_111551.jpg
 
The op hasn't been on here since he started the thread. We need some answers from him before we can help.
 
69_340_GTS said:
Now, that would be a huge mistake! The Eddy heads have heli-coils in all the threaded holes. You never tap a heli-coil.
Click to expand...

I run stock heads, not Eddy...

If he's galled the threads by trying to put them in and they get tight before reaching clamp load, then they may need to be "freshened up"...

Damaged threads will not give proper torque or clamp load...
 
Engine block has no alignment pins. RTV sealant was used at front and rear. I tried threading in the longer bolt in a few of the holes and it went well with just a 3/8" wrench, no real binding, just felt as a normal snug fit. There appears to be about 3/4" depth of thread in the head and it opens up in to what is probably a water jacket. I may have made this a larger issue than it is, just want to be sure it is sealed. I believe the longer bolts will work. Thanks for your interest and opinions.
 
wafastr said:
Engine block has no alignment pins. RTV sealant was used at front and rear. I tried threading in the longer bolt in a few of the holes and it went well with just a 3/8" wrench, no real binding, just felt as a normal snug fit. There appears to be about 3/4" depth of thread in the head and it opens up in to what is probably a water jacket. I may have made this a larger issue than it is, just want to be sure it is sealed. I believe the longer bolts will work. Thanks for your interest and opinions.
Click to expand...
Anyone else like anti seize on the bolt threads with aluminum heads...?
 
krazykuda said:
I run stock heads, not Eddy...

If he's galled the threads by trying to put them in and they get tight before reaching clamp load, then they may need to be "freshened up"...

Damaged threads will not give proper torque or clamp load...
Click to expand...

That's great, but the O.P. says he has Eddy heads, and you are telling him to tap them...
 
69_340_GTS said:
That's great, but the O.P. says he has Eddy heads, and you are telling him to tap them...
Click to expand...

I didn't catch that they were Eddy heads...

But if the threads have been galled, they need to be made true again...


Why does Eddy use heli-coils in the heads when you can tap into aluminum without them??? I worked at a factory that tapped threads into aluminum heads and blocks... We only used heli-coils for repairing damaged threads....
 
I’d say they use stainless steel heli coils because there stronger than softer aluminum.
Also, most bolts are steel of a sort. Ow you have two dis similar metals. Not good.
 
I'm sure Edelbrock is trying to avoid stripped threads. It's just good practice when dealing with soft metals. For example, in the aircraft industry, you almost never see aluminum parts without helicoils.
 
e-z-lock.jpg
I like the looks of these thread inserts better than the Heli Coil's. Drill, tap oversize, locktite and screw them in. Permanent fix!
Let me find the photo. E-Z Lock brand.
 
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