bolt size for intake manifold on a 318/360?

[shadango]

Anyone know what the bolt size is for the intake manifold bolts for my 318 with 360 (J) heads?

Also, do you know if the bolts can be a little longer than stock in an effort to grab past some bad threads?

Thanks all

[Changin Gears]

If you have some bad threads, I would be looking at studs.

[shadango]

Well, one bolt wont tighten (front drivers side, second bolt back)......was thinking of trying a bolt that was just a bit longer...

Can you explain about the studs? 

[shadango]

Found a bolt kit on edelbrock's site...appear to be 3/8-16.....but no lengths....

The description says that their bolts "are specifically designed for use with performer manifolds"....

I thought a bolt was a bolt....

[Changin Gears]

I don't know why, but I was thinking head bolts..   The threads for the intake bolts are pretty shallow, so if they are stripped a longer bolt won't help.  However the bolts do extend into the head.  A quick and easy fix might be to pull the valve cover, put a longer bolt in, with a nut on the other side (if it doesn't hit a push rod).  Real fix is a heli coil.

[shadango]

I just had the covers off too...didnt think to look to see if the bolts go into the head there....

Well, that would be a good temp fix, eh?

[Changin Gears]

Thats what I'm thinking

[shadango]

Will have to yank that cover and check it out.

Guess that in order to helicoil (safely) the head would need to come off.....? Otherwise would get drill shavings where they shouldnt be....

[HemiOrange70]

http://www.moparts.org/Tech/Archive/smallblock/2.html

[shadango]

Thats a GREAT link!  Thanks very much!

Just to refresh me in the event that I do have to pull the manifold....

--remove carb....
--drain coolant (how far down do I need to drain?)
-- disconnect upper rad hose and heater hoses
-- 12 bolts and she is off......

right?

Any tips/tricks/things to watch for?

[Chryco Psycho]

You don`t have toi drain it down very far , you usually have to pull the dist to get the back bolt out just pay attn to where the rotor points before you pull it

[shadango]

I know this is a hugely old thread but wanted to update it.

Since the car has some down time right now I looked at the bolt sitiation again.

I decided to try threading in a longer bolt in and lucked out by having one that was a little less than an extra 1/2" long.  It seems to have worked!

I actually found i had TWO bolts that were not threading tight so I replaced them both.   They seem to hold tight now.

Wondering -- are the bolts for a performer manifold different than a stock manifold? My car is a 318, but it has J heads.

The two bolts in question are the very front on the driver side and then one bolt behind that one too....looking at the front of the head, you can see the area the bolt threads down into...I probed it and found that the threads seem to go more than a half inch further into the head than my bolt was reaching, so I tried it.

Wondering if maybe the performer manifold needs longer bolts?

[Chryco Psycho]

sometimes the intake is cast thicker  so the bolts would need to be longer

[shadango]

Maybe that's all it is/was.

All of the bolts that are on it look "original"...they all match etc....except for the 3 I added....

Just glad I was able to do it.

[Aussie Challenger]

Always pays to check hole depth and then run a bolt down to see if it goes in to the bottom of the hole, also that the bolt goes down past the thickness of the manifold or what ever you are trying to clamp down.