Originally Posted by Budman II

You know, I wish more aftermarket manifolds came with the rear water passages drilled and tapped. My Dart intake did not have provisions for this, or I would have added some hoses here to promote better flow to the rear of the heads. I don't think I want to take a chance on trying to drill and tap these with the intake on the engine. Of course, I am running a circ pump, so it may not be an issue.

Originally Posted by Black Baja

Tim, here is an idea and I've tested it. It works. If your intake has a bypass hole in it under the thermostat you can run a small hose from under the thermostat to the top of the thermostat housing (I used -6 or -8 can remember) I had a bunch of 1/16" holes drilled in a 140 "car thermostat" and my temp pretty much stayed at 135. If you don't have the bypass hole in the intake it wouldn't take much to drill and tap it to 1/2" pipe. Just an idea it works. At least this way you are heating the bypass water through the motor. Just block off your bypass on the crossover and don't use it. At this point it would be a cost effective way to get a little bit of temperature in the motor.

Originally Posted by payuppsucker

I did this very thing when I first installed my new power. Worked ok but water pressure was extremely high, 55 at around 4,000 rpm. This was with a -8 hose.

Originally Posted by payuppsucker

I wasn't knocking your setup, hell that's the way I wanted to run mine. I just wanted to alert Tim of possible high water pressure.

Originally Posted by Young Performance

I've used the Hardin crossovers with their thermostat housings with the divider in it with good success. I still find myself having to drill a few holes in the thermostats to A) lessen the water pressure a bit and B) send a little more water to the exhaust when the thermostat is closed. I also like to have a way to expel any and all air that can get trapped beyond the thermostat when it's closed.
They will all generally have water pressure issues without some holes drilled in the thermo. A bunch of the setups out there only use a 1/2" or 5/8" hose for the bypass. You have (2) 1" hoses feeding the exhaust. The crossover is being fed by 1 1/4" hose. How in the hell can you possibly remove all of that water through a 1/2" hose. You can't. So, the water pressure spikes. The new Hardin setup uses a 1" bypass hose so it doesn't cause nearly as bad of a water pressure spike. Combine that with a few holes in the thermo and you have a really nice crossover setup.
Eddie

Originally Posted by Full Force

My bypass hoses are 1" my kit is older Stainless MArine setup.

I gotta buy the stats Joe posted for this coming weekend I am gonna play with restrictor plates..

Originally Posted by MER Performance

I will share my experience with by-pass crossovers. The best water crossover is the one from Stainless Marine, the thermostat housing is cast polished stainless, that has a diverter in which keeps the cold water from confusing the thermostat with cold water. That cold water will, make the thermostat close early NOT ALLOWING, the water to flow the hot water from the last 2 cylinders on each bank. You will never see a high temp reading on the gauge, allowing the rear cylinders to overheat, causing the cylinder head to expand beyond the quench of the gasket.
I experienced; a confused thermostat on a 750 hp 540 NA I was told drill 5-7 holes in thermostat. This issue cost me much time and $$$$, the end result of the cold water hitting the top of the thermostat, wasn't a enjoyable journey, for my clients lost boating time and my time and money to correct the issue. the end result was a dropped valve seat and a bent valve. After repairs were made, a thermo-heat gun determined, 300 + degrees in back cylinders. determining what was going on. The only bypass I us now if needed is from Jerry @ Stainless Marine.