Carb Bolts

Finally took off the carb for a rebuild - it's been on there for more than 10 years.

The front drivers side bolt busted. Tried vise grips, PB Blaster, and heat with propane torch. Finally had to drill it and use an extractor. Note that the square extractors work better than the spiral type.

Three of the bolts are 5/16" and one is 3/8". Both front bolts are necked down a bit below the head. Why? The one that broke did so at the narrow part.

The bottom of the base plate is recessed to make a passage between the two small holes outboard of the main bores on the intake manifold. What's the purpose?

Do I need to find new specialty bolts or can I just use regular bolts?

 

hmmmmm just checked and my bolts ae the same way...i currently have mine apart too.... i dunno....someone here will have the answer

 

So you're saying that it's not a special bolt that is necked down to allow room for the air to get by?

And, you're saying that it's exhaust gases going up through intake manifold and under the carb?

 

Ok, got it on the bolt.

I'm still curious - how does the exhaust get from the outboard side of the heads (where the headers attach) to the top of the intake manifold? There must be a passage through the heads?

 

There is a passage thru the exhaust port that goes thru the manifold from one side to the other side passing thru the bottom of the carb. You can also get a carb gasket that blocks this, I did. Use Stainles bolts, coat them with anti seize and forget about the corroded bolts.

 

Thanks guys.
I feel smarter knowing this.

 

My manifold is at the machine shop right now. The 2 front bolts were rusted so bad they spun right off with almost no effort. What's left in the manifold looks to be almost "welded".
I will reinstall with stainless bolts!

 

Just a suggestion.. use the copper colored high temp neversieze.
Also a few tricks on bolt removal.. spray with wd40 let sit for 5 min. then use pvc cleaner and dab that around the stuck bolt and let sit for another 5. The reasoning is the wd works in good but the pvc cleaner being a solvent and much thinner will wick inbtween the threads and dissolve and carry the wd40 with it. Then using vice grips, extractor or whatever the problem warrants will be MUCH easier! I've used this method on exhaust manifold bolts that the heads are almost non existent and works very well.