intake bolts being stuborn
 

I was installing a new Edelbrock intake manifold on a sbc350. Out of the 12 bolts the four in the center made me crazy. All of the others drop right in. If I attempt to install only the inside four then it does not seat and the rest wont line up. After fifty or so attempts I gave up. I screwed the bolts into all of the 12 holes without the manifold and they thread real nice. Being at the end of my hoes I decided to just use the outside eight. Last night I fired her up for the first time. I was orgasmic! My friend noticed the holes on the inside four are empty and he believes that oil will eventually come out of there. after several attempts to drop in the inside four he also gave up. The bolts all go in on an angle. So I definitely don't need one of those thread hole kits for the bolts that shoot straight down. Why in the world wont they start? If I leave them as is will oil come out? I really don't want to remove the carb,alternator,a/c compressor, all the wiring, the distributor, all of the plumbing, and the sensors to get at the manifold so that I can re-seat it again only to find that it won't seat with the four inside bolts. I mean it would not work the first fifty or so times so why will it work now. Maybe if i grind down the sides of the end of the bolt it will force itself in?

Sounds like the manifold wasn't drilled right. This is seen much more often on offshore intakes than those made by Edelbrock.

Are you sure the intake gasket isn't the problem? If not, you can grind the intake bolt holes as needed to get the bolts to line up- just don't cross thread them!

One more thing- be sure the bolts aren't too long, else there are a couple that can hit the pushrod. IIRC, intake manifold bolts for cylinders 4 and 5 should not use 1-1/2” bolts, use 1-1/4” at the longest.

I will definitely give it a shot. Good to know on the bolt sizes. Maybe I will call Edelbrock and see what they say.

Are you sure your block was never decked and your heads haven't been milled? With a new intake it would be frustrating to have to modify. But if things aren't coming together properly in your mockup install you have to do something. You may consider using the extra thick intake gaskets. Mock it up, if you're not having success then either send it back (if they take it) or drill out the holes. Can you get a mag light and look down in there to figure out what the obstruction is? Is the bolt getting hung up on the intake gasket or is the hole too far off center of the threads?

K

I called Edelbrock. From what I can tell the block i have is a later model since the valve cover bolts are in the center of the valve covers. That means that the four bolts in the center shoot straight up and down instead of being on an angle like the other eight. So my choice is buying a new intake, or trying to drill out the four holes to accept the bolts. What would you do? I have never drilled out a manifold, however I have drilled out many things in the years of rigging. really do expect it to be that big of a deal.

If its new, and you have a receipt...exchange it. Ask around, someone may have done a Vortec head swap and have the intake you need as a doorstop.

A machine shop could probably drill those out for a few bucks. I wouldnt do it with a cordless hand drill for example.

I seem to remember a port/gasket mis-match. You may have an intake leak if you try to use it. Start with the right parts for the application.

I had a similar situation with a too thick gasket.

intake bolts being stuborn
 

Look on the flange behind the alternator and post the numbers for the block. Pull the valve covers and get the casting numbers for the heads and post them too. There is also a casting number on the back of the engine where the transmission bolts to the block. Can be on the drivers or passenger side. Like was mention before you might have vortec heads which uses a different manifold.

It's the heads that matter, not the block. A Gen 1 SBC block will accept heads from 1955 to the end of the Vortec run in 2002. The heads you have w/the 72 degree center bolt hole angle were used between about 1987 and 1995 except aluminum headed Corvettes.

You can elongate the bolt holes of the intake (some info here). It's no big deal. But if the intake can be returned for the correct one, that would be the preferred way to go.

Some of these heads were used on TBI equipped truck engines and were called "swirl port" (or "SP") heads. Casting numbers 14102191 and 14102193 are seen most often. They do not flow well at elevated rpm- like above about 4500 rpm or so on a 350 cid engine. If you have SP heads, consider swapping them out. If you swap them, you might as well bite the bullet and get Vortec heads if you cannot afford aftermarket heads. The Vortec heads are worth as much as 50 HP more than traditional Gen 1 SBC production heads. They do require a different intake manifold than 1985-back heads, so that's something to consider if you were going to have to buy a new/different intake anyway.

Edelbrock pn#2604 is what your needing my friend.....

Au contraire. I personally don't recommend the air gap intake. This has been discussed a lot, and recently to boot. See http://www.hotrodders.com/forum/air-...pm-224531.html.

That IS the right type intake for the 1987-'95 heads, though... ;)

Lol......I was actually just flexing my googling ability for "an" intake that was more appropriate then dremeling holes to make his fit....but now I have to go search around for what the heck your referring too as I'm about to purchase one or the other myself, (air gap or performer rpm) ....great....more time with my tablet.....my hates me....and now you lol....

its the center bolt hole for the later heads, I can't beleive its taken this long to get an answer... I knew it soon as I read the first post, you need this model number Edelbrock 2104 SB Chevy 87-95 Performer Intake Manifold | eBay

Unless you are running a TBI setup then you can use this..

Thanks so much for the info. I took it off the block and reamed out the center holes with a file, reinstalled, and torqued done. Worked great and no leaks. Now she runs like a raped ape!