Have a look at the front of my LG4 305 in the picture below. There are 3 threaded holes in the head on one side and only one on the other. This is no problem for that particular engine, but, I have another camaro (1991) that I am putting a 350 in, from a 1977 Chevy Pick-Up Truck.
The original 305 LO3 has long since blown up and been scrapped, and I am only left with the 2 ally brackets that hold on the accessories (alternator, A/C, AIR etc).
Don't these 2 brackets need all 3 holes on both sides? If they do, they wouldn't fit on my LG4 motor. I thought that they would fit any 305 or 350 block of any age. Are they going to bolt on to my truck 350? Unfortunately, the motor is away being rebuilt, so I can't check.

Any thoughts?

Thanks.
Andy.

 

I would have expected someone else to answer by now. Since my exposure is to the older models, my info my not be accurate.

I understand you need more holes on the later systems. The good news is that heads that have any bolt holes at all will have enough material to drill and tap the other holes. That isn't the case on older heads like the famous pre-'68 "double hump" heads.

 

You NEED the two holes that are missing on that head. I bet if you turn the other head around you might have more holes on it. Look at both ends of the heads and think about how which one will on what side in order to have 3 holes for each head up front. Not that important for the back.

 

I got everything hooked up fine without the extra holes.
No problems and 11,000 miles so far....