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glinder46 03-25-2017 11:43 AM

70 SS454 Fan Shroud Problem w/DeWitt AL Radiator
I had some mods done to my 454 including Vintage A/C which gave me a heating problem. I ended up solving it with a DeWitts Aluminum Radiator. Great choice but i have some issues with the fan shroud not fitting properly. The 70 uses three top mounting bolts and two clips on the bottom. I used DeWitts insulators top and bottom. If I mount the top bolts up high for fan clearance the bottom clips won't engage (too short) If I push the shroud down 1/4 in the center bolt hole is too far down to engage the top radiator surround. Any suggestions would be appreciated. I could buy an original GM shroud but it is 3x the amount of an aftermarket.


George Linder

shadowgray396 03-26-2017 10:26 AM

Are you saying top plate is using 3 bolts that covers the radiator?

Ken Hayes 03-26-2017 11:48 AM

I take it the 454 is not the original motor for the car. My 70 only has 2 upper mounting bolts for the shroud, that bolt onto the top radiator hold down plate that has 4 mounting bolts. Sounds like you don't have the right shroud.

glinder46 03-27-2017 01:02 PM

The 454 was the original engine but from what research I have done one of the SBC engines may have had three attachment points. What is funny is that the Assembly Manual shows the same top plate on all engines with the exception of the Chevelles that came with 6 cylinder engines. I do see on some of the restoration catalogs a three attachment bolt kit but it leads to SBC as well. GM if they ran out of the top plates could have substituted this one. I have the build sheet and know that there was only one owner retail wise. The car was owned by two dealers after that. I am going to try stock cushions which are not as large to see if it fixes the problem. It is amazing that even fan clutches that they say are direct replacements usually aren't, too long on the attachment end or too short. I am trying to run this one down as well. The fan sits to far into the shroud by about 1 1/2 in. so the blades are totally into the shroud which is also wrong.

Thanks for the reply,

George Linder

glinder46 03-27-2017 01:06 PM

Sorry, I missed the first post. No the top plate covering the radiator is 4 bolt. But there is a center opening for another shrould attachment clip and bolt between the two that most shrouds attach to on the top.

John 07-07-2017 12:41 PM

I had that problem. To get around it, I zipped tied the bottom of the shroud where it no longer met the clips. Yeah, I know-pretty lazy but the problem was solved.

glinder46 07-07-2017 01:11 PM

I finally solved it as well. I bought a NPD fan shroud which is a tad bit longer than the one I had from OPGI. I was able to use the clips that are stock. Now I am searching for an appropriate closed cell insulation to use on the sides of the shroud to radiator. I have about a 1/2 in gap and it prevents the full flow thru that I want.


John 07-07-2017 05:07 PM

I went to Home Depot. They have a 3/4 thick black insulation strip that worked great. It's in the door section.

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