Loosing Coolant Suprise.

[man7sell]

I have been loosing coolant rapidly. I know the heater core was bad but it had been bypassed. So got a new heater core and connected it up. Checked all my hoses and replaced a couple. All the rest are good.
Stilling loosing.
No leaks under the truck (Put a piece of white cardboard box under and ran the truck then let it sit over night...... couple of oil drips only.)

To drive the truck any distance (Like to a radiator shop to check the system) I had to replace the rotten, broken exhaust. Fitting a nice system on there, started the truck to see how it sounded, very nice but wait what's this???? Coolant coming out both tail pipes!!!!

What's the common denominator as both exhausts are separate, coming from separate heads.

The intake manifold. Darn, now I have to change that for an Edlebrock