Twin 496s with open/raw cooling.
I think I want a mechanical gauge under the the engine cover/area so that I can confirm I have good flow/pressure when I start the motors and idle around. I believe I want to watch for signs of age/wear on my impellers/raw water pumps by making sure that my flow or pressure is sufficient.
Should I get pressure gauges (style, brand, and installation location recommendations) or flow gauges (same questions)?
THANKS,
Tom

Tee fitting on a block drain is where mines installed 502. Mechanical gauge and used 1/16 air brake tubing to the helm. Others have placed on thermostat housing and others Tee fitting with water pressure sensor on power steering cooler.

Mentioned to Tractionless that one of these days I'm going to check the thermostat place to check differences, still wainting.

Thanks, Water pressure or water flow? Can you tell me what brand? What's everybody else doing?

On my last boat I had a Gaffrig or Livorsi setup. It came with the tubing and the fitting to install it... I ran it to the dash which I really liked because I learned that a few more rpms coming off of plane really added a bunch of pressure to help cool down the engines after a long run.

Mine is raw water cooled and it reads pressure.
I have a 0-40 psi VDO mech gauge

Idle cold = 3-5 psi
Idle after run = 1-2 psi
First part of run = 22-24 psi
After about 10 minutes = 19-21

I want a 0-30 gauge but VDO didn't make one

Planning to redo my helm this winter and going for new gauges. Have heard Lavorsi is made in USA

Thanks to the above responses...

I run 2 autometer water pressure gauges in the dash...one for the cooling system and one for the intercooler as I'm supercharged...the intercooler sees nothing unless I'm moving as it has its own dedicated transom pickup with no pump...I also don't see much on the cooling system unless I'm moving because I don't run a thermostat and have very little restriction in the system. I was running the pickup for the cooling system in one of the block drains however I plan to move it to either the oil cooler or the thermostat housing because its very easy for sand/silt to plug the block drain hole and the gauge stops working causing me to panic hahaha. If you run a thermostat I would suggest the gauge be pre thermostat to get a real idea of water pressure because after will only read accurate if the thermostat is open.

Can you take a picture of how/where the mechanical gauge hose is hooked into the raw water system? Thanks

I'll take a pic if needed but see if this will answer the question.
I removed the Merc bushing and Hardin Marine plug. Get a 1/8 NPT Tee fitting and a 1/8 NPT male x 1/8 compression

Place the 1/8 compression on the upside of the Tee. Placing on the upside will help keep sediment out of the line. I'm also in fresh water so sediment will be less.

If you have just a 1/8 NPT plug just remove it, install Tee and compression fitting then reinstall plug

That should work! I'm just learning this boat (Formula 311 with big blocks) and just moving around/looking in the engine compartment is tight! That being said, I will look for this set-up on my blocks.