rfpowerdude

Ok, I have a 1970 Cutlass S that originally had a 350/4BBL/TH350 that I am putting in a 455. However, it seems the radiator that I have that was included with the car (not installed) is oversized for the hardware. It doesn't quite fit and seems to be about an inch too tall.

What should the actual dimensions be so I can buy a new radiator that will fit? Seems like there is a 17" tall version and an 18" version. Were 350 powered cars 17" and 455 powered cars 18"? Also, seems like the thickness is different too. The one I have is def too thick to actually fit.

And then, sources of a new one that will fit AND keep it cool?
Thanks all,

Fun71

From what I know, the radiators all had the same width and height. The difference was the thickness: 2 row, 3 row, or 4 row. The 2 and 3 used the same end tanks, so the same top plate and saddle width. The 4 row had thicker end tanks and used a different top plate with wider saddles, along with wider bottom saddle.

You could bolt your top plate in and measure the height to see what would fit.

rfpowerdude

The availability of radiators online show two different heights, one 17" and one 18" tall. Also, the radiator I have is 3" across where it meets the top rubber isolaters, but the top plate seems to want something that is not 3", but something less like 2.5-2.75". Same for the bottom isolaters. It's the same thing down there. The radiator is too wide/thick for the rubber mounts and they look like they are original.

I'll go out there right now and put the top plate and shroud in and make some measurements.

SY2455

Taking rough measurements for you as the car is still together. 1970 W-30 measurements are 19" high 29" wide 3" thick. These are the rough measurements of the core only ( not counting the tanks ).

olds 307 and 403

One thing you will want to do is convert to the 4 core saddles for a 455 car. I did, got them from Thornton Muscle Cars and installed this radiator, fits like a glove and cooled my 9+ to 1 Olds 403 with ease. Unfortunately Thornton is currently out of stock on the 4 core brackets and rubber mounts.
https://www.ebay.ca/itm/351157989603...mis&media=COPY

rfpowerdude

Ok, I measured. It's 28-1/4" wide at the mounts and 18" tall at the mounts. However, the mounts themselves look like they can only accommodate about 2.5-2.75" wide at the mounts. I went ahead and ordered the that radiator you posted. If for some reason it doesn't quite fit, I'll buy or modify what it takes to make it fit correctly.

And I will likely need a 4 row top plate. Time to text the usual suspects on what they have in their stash...

olds 307 and 403

It fit my 70 Cutlass S great on the 4 core mounts in place of the factory 2/3 core mounts. Running Dodge Stratus fans as my car was a no shroud 4 blade fixed fan car.

joe_padavano

You can fabricate a four row top plate from a two/three row top plate. That's what the factory did.

rfpowerdude

Thanks Joe!

olds 307 and 403

Exactly what did as well, drill out the rivets and put in the 4 core top mounts. Hopefully someone has the 4 core top mount and cushions available. I bent the bottom saddles to fit the bottom rubber pieces.

rfpowerdude

Thanks guys! I have also ordered a cheap replacement radiator and will use that to flesh out any issues with what I have now before I do the mods to accommodate the big radiator I ordered.

rfpowerdude

I went ahead and ordered these since Thornton's doesn't have them right now.
https://www.inlinetube.com/products/inl11050