Hi everyone I'm after head specifications for the 305 TBI lump put in camaro in 1990.

Basically had a bunch of exhaust bolts snapped, replaced them all but one, to which the drill bit snapped, and I'm struggling to get it removed. I want to know on the passenger side of the engine 4th hole from the front of the engine if any water/ oil ways go through the head about 15mm towards the back of the engine so I can re drill a new hole.

Picture to be uploaded soon.

 

Yellow X marks were I want to drill.

 

if you get a good punch you can shatter the bit and get it out. I work on Armor (military) and thats how I do it. they call me in after its all fuc*ed beyond repair and I fix it.

 

Sounds like a good idea, but it's pretty cold hear and I know cast irony can shatter a lot easier in very cold temperatures.
One thing I don't want to do is crack my head.

 

It's casting # 187... widely hated and reviled as a "swirl-port" low-perf piece.

Best plan might be to just replace it. Shouldn't cost much; people might even pay you to come haul that garbage off their property, if they have any of em laying around.

You could in fact boost your car's performance noticeably by swapping on a set of 081 castings, the TPI/carb 305 part.

You can't really drill a hole where you have that white "X", if that's what you're thinking. There's nothing behind there to drill into. Where the bolt holes are, there's a nice thick boss below the surface; but there, all there is, is the water jacket. It's about 1/8" thick and of course goes right straight into water.