I have the one true fix for this Problem.Sense I've logged more miles on my 1965 3/4 ton them most of you have own any Truck or Car in your life time.
My family buy a 1965 3/4 ton from sun kiss orange company back in 1969Trust had over 150,000 hard miles.It was a 283 2 speed power glide with the power assisted steering.
It leaked more oil on the way home and smoked really bad.My grand father and his 2 sons worked on it an got a 327 for it an did a mild rebuild back in 1970.
Motor lasted for 2 years and died.In 1982 they put in a 307 it ran until 1993.
That's when i got it.My father one of the grand father sons.My dad gave me the truck an bought me a 350 motor from a engine rebuild place with a RV came in it.
From 1993 until 2016 I started out in the scraping back in 1990.But got into his heavy in 1994.
Bought me a few tandem axle trailers one for cars one for scrap and later one as a 10X6 dump trailer in the house clean up business for rentals in 2002.
Now my truck has gone throw many changes But learning along the way.Updated the brakes with a new 1972 front end New power steering on the frame sway bar disc brakes. power brakes.
Learn about bad Idea;s that GM came up with and should of changed or put out a bulletin on how to fix it.
Now i'm now 47 and I've got a life time of knowledge.that i'm trying to pass on.
The Chrome swivel peace on that engine is so wrong after 1-3 years they leak.Its funny to watch when you have a Steam monster running down the freeway and watching the engine explode.
I hate anything with a O ring that deals with pressure and HEAT.Not a good Combo!!!
GM made 2 thermostat housings first was the cast iron then they made the alum.Me i'm more of the cast iron but there hard to find.
So now they make a aftermarket straight out alum housing that will work all edalbrock
manifolds.Witch i Love.
Reasons why i love them is for are 1960--66 chevy trucks 1/2 ton to 3/4 ton or 3 ton bob tail dose not matter MY system works.Its proven over 10 years.
With the picture i will show you i will make it easy it will look factory and it will not look like Trash.
Finally The 2 parts that make this work for all 1960--68 chevy trucks they made 2 hoses.But the 1967-68 once i feel works the best with a fan shrouds.
Now this one can not be done in house you need to take your radiator out of your truck and take it to a radiator shop.
The Radiator has a bigger hose bib on the upper radiator hose opening then on your thermostat housings.You have to make them the same size so one hose fits both sides.Kinda stupid from what I've seen.
Most radiator shops understand when you bring it to you Now alum radiators Know of the problem and its fixed for you.But this is for Brass and copper radiators only from 1960--66 trucks
Now I have a new helper for you.It will cool your truck and will last a life time using most of the factory parts but 2.
Now fan clutch is for a 1974-75 454 and the 7 blade Dodge Fan blades the numbers to look for are 46237.There where the fan clutch goes throw the circle it will be stamped.
By using this Fan clutch with the extreme duty 1974-75 454 fan clutch and using the small water pump This thing will give you so much cooling but will not rob you of HP.
The upper hose to look out for is #3898556TH GM/AU upper Radiator hose
The thermostat housing that your looking for is on
WWW.truckandcarshop.com part number yo look up is for the straight out housing #60-10608
This is why i use this system.One you can use the hole for the temp sending switch on the intake manifold
Parts and numbers and some prices
The upper top hose is #
The thermostat housing # 60-12608 1960-66 V8 engine 19.00
the sending unit number # 60-12802 1960-72 USA one is 25.00 after market is 13.00
The factory engine harness for the stater temp HEI and for gauges only is $85.00
the factory engine harness with HEI with out gauges is $85.00
That is a Brand new harness a plug an play system
Here are some pics to help you to get it done right my 1965 has been retired for 2 years,Bus she getting a rebuilt sm block 400 in 1 year right now is the old 350