That sounds like a great project! Hopefully we can contribute somehow!

'85 720 here and building a Z24ET, stuck with the exact same dilemma.

We do have an adapter for 3/4" barb but we are looking at adding a new AN based pump in the future. The adapter is here: aeroflowperformance.com/af741-12-12blk-3-4-barb-to-12an-adapter

You can utilise the factory cooling system however it will be much less efficient than a stand-alone system since the water/coolant will be already at regular engine operating temperature - and that is generally higher than ambient temp. We would recommend using a heat exchanger and yes you need to mount it in a location that has air flow

Hi Kent, they will work no problem, you just need to size the core appropriately and have a large reservoir with heat exchanger to keep it consistent. There's only so much heat the water (or coolant) can take out before it needs to then be exchanged again in order to keep cooling for a long period of time.

Depending on the setup, ice used or size of water reservoir you could get down to single digits but even with the smallest core we see starting temps in the mid-teens and finishing in the 20s. This is all relevant to power level and efficiency of the setup but in comparison an air to air intercooler will rarely see below ambient temperatures

Generally it's better to have a separate system, as we described at the start of the video, for maximum performance. You can also run it from your engine coolant system although you may need a higher volume water pump to keep things moving

You can use the cars coolant system but then you are stuck with a minimum charge air temp of 90*C or the coolant temp that engine runs at even if its 0*C outside as cars coolant always run at same temp regardless of outside air temps (mostly). If you use a separate cooling system with its own coolant you can keep that coolant at ambient air temp or even lower if you add ice to the coolant or alcohol based coolant, allowing the charge air to be much lower, problem is once that seperate cooling system is heatsoaked then it looses effienciency but its still better than Air to air, Specially Top Mounts. But there is a lot of extra Weight, complexity and chance for things to go wrong with Water to Air.

If you are still using the same amount of coolant in the system then it's probably about right. The surface area of the cooler is larger which will allow more heat transfer however if you don't have a larger capacity for fluid then the same amount of fluid is exposed to the same heat source for the same amount of time. I hope that makes sense!

Of course, you could weld a bung in to the inlet and outlet side

There's always pro's and con's for both but generally we find water to air is more consistent at most Ambient temperatures

These intercoolers are completely universal so you can use it in any application that requires cooler charge air

Yes and no, the water to air is going to give you a much more consistent intake air temperature and the required area for the heat exchanger is generally smaller than an effective air to air cooler. Air to Air is definitely easier and less complicated to setup though