Slant 6 to V8 cooling

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John Cailey

John Cailey

Crizila
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Transplanting a 318 Magnum motor where a /6 used to live. Core support opening is too small for a V8 radiator. Any suggestions would be appreciated - before I start cutting. Thanks, John
 
74 Duster - original /6 car. Just read another thread on this subject. I have a new stock V8 A/C rad that looks like it is gonna sit too high unless I do some bottom core support cutting. Will also have to drill some new mounting bolt holes ( wider ). /6 core support opening ( width) is also a few inches short on both sides. I guess I just gotta start chopping away. UGH!!
 
I just swapped a /6 for a magnum and just bolted in my new radiator with no problems . I did have to drill a couple of mounting holes ? What are your radiator dimensions ?
 
I've never had to cut the bottom of the core support. A 74 Duster should have at least a 22" opening, plenty for a hot 340.
 
You sure you have an Abody radiator? Never seen one that wasn't bolt in.

I have seen aftermarket ones that need width trimming of the sheetmetal to eliminate shrouding of the radiator.
 
Core support opening is 22 5/8" wide by 16 3/4" high. Rad core is 25" wide by 18" high. Rock Auto replacement rad for a 74 Duster with 318 motor and A/C. Don't have the hood on the car yet and height is my concern. Don't want to have to modify the rolled section on the bottom of the core support, but I might have to ( slightly ) to get the rad to sit low enough. I will bolt on the hood today and see where I am at. Drilling new mounting holes ( which I will have to do ) is not a problem. I am curious if Ma Mopar installed different core supports for the /6 verses the V8 motors? Thanks for everyone's input. Again, new to A body stuff.
On another note, Had to shorten the drive shaft 3.5" to accommodate a 727 verses the 904 slant trans. Also slight mods to column shift linkage. Linkage did clear the headers though.
 
SOme of the rock auto stuff fit various applications or they aren't built to exact OEM specs.

Just throwing this out there. I'd made sure you have a quality radiator that will do the job and fit properly. DOn't skimp or play around when it comes to cooling.
 
John Cailey said:
74 Duster - original /6 car. Just read another thread on this subject. I have a new stock V8 A/C rad that looks like it is gonna sit too high unless I do some bottom core support cutting. Will also have to drill some new mounting bolt holes ( wider ). /6 core support opening ( width) is also a few inches short on both sides. I guess I just gotta start chopping away. UGH!!
Click to expand...
I remember having the same issue, I took measurements..then went to the wrecking yard and walked out with a 40.00 dollar radiator. Been using it since 2003...3 diff motors...bigger and meaner, it cools them all. I made it work by using a slant 6 hose on the inlet and a regular upper v8 hose.

You'll figure it out, I have faith in you.
 
Mounted the rad today. Put the hood on and checked clearance. Not a problem. Lots of hood clearance - 1.5" using clay on the rad cap ( highest point ). Used some 3/8" thick dense foam rubber between the bottom tank and the bottom of the core support. I'm good to go. Rad is for a 318 with A/C, so I shouldn't have any over-heat issues. This motor will be making slightly under 300 HP. ( my estimate ). Probably do a 16" flex fan and shroud when I get that far.

V8 radiator1.JPG


V8 ragiator2.JPG
 
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