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4 Barrel Conversion Questions

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4 Barrel Conversion Questions
« on: July 06, 2019, 10:53:17 PM »
Hello Everyone,

I am in the middle of converting my TR8 from Strombergs and hit a snag.

I purchased an Edelbrock manifold from Woody and when assembling everything on the bench I noticed the new manifold is one coolant outlet short.

While surfing for answers I noticed a lot of conversions had one of the outlets on the water pump blocked off where the hose from my missing outlet would run to. Even on the page that Woody has showing how to install the manifold, the water pump is blocked off. Am I supposed to block off this outlet on the water pump? Or will I lose the use of the heater or worse?

Also, when running the hose under the manifold in the V, do you need to secure or just let it sit there?


Terry B



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Darrell Walker

Re: 4 Barrel Conversion Questions
« Reply #1 on: July 07, 2019, 09:52:28 AM »
Hi Terry,

For the heater line, I made a tube to attach under the manifold, much like the

original.  If you are using all soft line, note that the firewall connection

isnbt the same size as the water pump connection.  Because of the angle that

it connects at the water pump, I think routing along the top side of the

manifold may be better, but I think either will work.

The other connection you are talking about is the coolant bypass.  Despite

theft that some say it isnbt needed, I think it is a good idea. What happens

when you have it blocked off is that you get wild fluctuations in the coolant

temp.  I think something like this happens:  With little/no coolant flowing,

the coolant in the block/head gets quite hot, while the coolant around the

thermostat and sender remains cool.  Eventually enough heat reaches the

thermostat, so it starts to open, and the very hot coolant in the engine moves

past it, so it opens up wide, the temp gauge climbs, and the coolant in the

engine is replaces by cool coolant from the radiator.  Which then moves past

the thermostat, closing it down, slowing the coolant.  So the coolant in the

engine starts to heat up again, the coolant in the radiator cools down, and

the cycle starts again.  Eventually this starts to reach some equilibrium,

faster in warm weather.  But I donbt think those swings are good for


The solution is to retain the bypass.  Woody puts a plug in the bypass port on

the manifold, you can easily knock it out.  Then you need a thermostat housing

with the bypass plumbed (Rover did it with a connection on the manifold,

rather than as Buick did it).  There is supposedly a Buick housing that has

the right output angle, or there is the one from D&D.  I went the D&D route: <>



Odd Hedberg

Re: 4 Barrel Conversion Questions
« Reply #2 on: July 07, 2019, 10:59:58 AM »
So did I on dads TR7V8 - never looked back.  It's THE solution...


On 2019-07-07 at 15:51 Darrell Walker wrote:

Ted Schumacher

Re: 4 Barrel Conversion Questions
« Reply #3 on: July 19, 2019, 09:41:54 PM »
We have the correct thermostat housing.B  Blocking off the water pump creates "hotspots". Ted

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