[rsbecool]

When using the 68 Z intake #610 do most people hook up the hose from the intake to the water pump (anti-cavitation)? Anyone have any problems not hooking it up?

[Vintage 68]

The bypass hose serves several functions - it allows a small amount of water to circulate to aid in warming up the vehicle, helps prevent any air entrapment in the upper manifold/block prior to the thermostat fully coming into operation and it helps prevent vane cavitation in high RPM operation.
That said, all earlier small blocks have a bypass circuit built into the stock pump anyway (it's the small hole just below the lower-left bolt hole) - so using or not using it will usually not cause an issue with cavitiation.
Big blocks do not have a built-in pump bypass. So use of the hose, or some other remedy, to prevent the blocked flow and air entrapment issues may be necessary if problems arrise.
The heater circuit on most early GM vehicles also constantly circulates water in the system to help any air to purge out of the system.

One common trick to prevent air entrapment is to drill a small (@1/8") hole in the thrmostat prior to installing. This will allow a small amount of water/air through and prevent entrapment as well as aid in allowing the thermostat to funtion correctly.
The above is specially important if you modify the cooling system flow or are not running a heater in your system.

I've plugged plenty of the bypass connections on truck and marine applications and never had problem one.
I guess it's up to you, if this isn't a resto where you need the 'look', then I'd just do whatever you want to...

Hope this helps.

[rsbecool]

Thanks for the information John.

[SY1]

Rene agree with John's comments above. Be aware that some aftermarket water pumps come with an allen plug inserted into the bypass hole on the pump to eliminate the bypass. Also some guys will install a plug in the block to serve the same purpose. Just wanted to mention it so you aren't counting on that bypass port to be working. You'll have to pull the pump to check if you want to be sure.

[rsbecool]

Sounds like it's not a bad idea to hook it up. Or is this redundant?