[Bermuda Blue]

It is unlikely that installing new dowels will increase the strength of location properties of the caps on the block. It is very difficult to sheer a 5/16" pin. Actually, the diameter of the pontiac dowel is 3 thou. under 5/16" if i recall. Installation of new pins becomes neccessary when the dowels holes in the caps become elongated and oversized.

An oversized dowel is larger in diameter. The dowels could stick out of the block quit abit without causing problems but it would make putting the cap on more difficult

You may not feel it but allot of caps will move around even though the pins are locating them. Take a dial-bore gauge and measure from the block to the cap. them push on the cap back and forth toward a motor mount bosses. If the measurement changes, you have a problem. This may be one of the most overlooked aspects of building a pontiac motor and the cause of many failures. If the cap moves enough, the oil film will be sheared and any a spun bearing is not far behind.

Removing these dowels is a real PITA. If you break one off flush to the block you have a nightmare on your hands. Once the dowel is removed, the holes in the block are reaemed (not drilled!!) to the desired diameter (this can't be done correctly with a hand drill!!!). The approprate dowel is pressed in while the block is heated. The dowel has to be larger than the hole by at least 0.0002" to ensure a tight fit. Then the caps have to reamed to accept the new dowels. Sometimes this is not necesary if the cap holes are already oversized due to them "walking".

Done correctly, it is not necessary to align bore the block because the location of the dowels and dowel holes in the caps has not changed.

I use a 5/16" + .0002 dowel and ream the block holes 5/16 exactly. The holes in the caps have to be exactly the dowel diam. to enusure that they don't move and at the same time allow you to install them. This is a fine line.

I have some dowels ($1 each) if anyone wants some. But they are available at any good machine shop supply house.