The squirt blocks also came with some early style and late style squirt nozzles.
The early nozzles had a much larger body, and thus a larger hole was drilled into main saddle.
The size was reduced in the later blocks.
The early 506 squirt blocks had the large diameter main bolts in both inner and outer positions as well as the large squirt nozzles.
The later blocks had small nozzles and the outer bolts were reduced to 10mm.
One of the big no no's in any of these blocks is the huge amount of stress risers all through the bottom end.
Before using any block, be sure there are no cracks in the main webs, then remove all the stress risers.
Carefully using a countersink to break all the sharp edges on all the main bolt holes is an absolute must
Chamfer the holes to get about a 1/16 wide break at the hole mouth.
Using a bastard file, break the sharp edges of the main webs to about 1/16 wide on a 45 angle
Use a 1/16" carbide ball in a die grinder and remove the knife edge at the base of the register fit where the main caps sit, especially the center mains.
This stops the tendency for a crack to form here.
Lightly countersink the starter bolt hole mouths as well.
Any sharp edges are an absolute NO NO
If there are any "clips" at the bottom of the cylinders where tooling nicked the lower edge of the cyl bore, these must be smoothed up and rounded so the stress riser is gone.
Think of it as a sharply creased piece of paper, and how easy it tears.
Carefully break the edge of the main bores using a die grinder and a "whip stick" or a sanding drum.
Lightly countersink all the oil holes in the main line.
Just breaking the sharp edge is all that's needed.
The dynamic forces at work in the bottom of these engines is a major player in the incidence of cracking, and "Dehorning" really adds to the longevity, or at least is not going to hurt.
This type of prep is a standard on any high perf race engine.
Will it stop all incidence of bottom end breaking, Maybe, but it's a step in the right direction towards stopping many of the failures.
These procedures take some time, but can be finished in an hour or so prior to the final wash out pending assembly.
Also, clean and run a tap through all the head bolt holes to remove all old sealer and to be sure the threads are clear and in good order. (be sure to use the proper metric tap)
if it has a sharp edge left by machining, fix it.
Nice rounded edges are what we want.
The addition of the squirt holes in the main saddles was a real nasty source of stress risers, and resulted in many blocks cracking through the squirt holes and then on up into the lower portion of the adjacent cylinders, usually hitting the water jacket.
The results were coolant loss and yuuuuuuucky oil.
Take your time and do the prep work, it will pay off.
Missy
