gleninsandiego

I have a 1969 350/350 project. I am pondering my future radiator needs for a higher horsepower engine.
It appears that there were different supports for this year. Big block, small block and maybe even more than that.
So far I can't figure out what support came with the L46 350/350.
I have had two of these and they both had a copper radiator and this support with a two piece plastic? fan shroud.

Here are pics of mine (sorry about the saran wrap) It measures 27.75 inches across the opening.


















Thanks
Glenn in San Diego

OZGreen69

This is the one you need 27 1/2 inches . this is the biggest "mouth" that you will find and correct for your 350/350!
I bought a Chinese copy as they are even bigger ( lighter! ) and grind it a bit more for my 2 passes alloy radiator.

terrys6t8roadster

Glen, those core supports are for the larger radiator. The top one looks absolutely correct for a 69, mine was a 300 hp with A/C which is the same as the 350 hp because of the A/C. Hard to tell one the second because of the cellophane wrap. Fan shroud looks correct, mine is boxed up somewhere, but I don't remember the clamp in the upper left corner or the hole in the upper right. Do you have the other lower piece? I also found somewhere that they sell a kit for the fasteners for the lower extension both female and male. That shroud in the cellophane sure looks nice. T

carriljc

That shroud (3956109) looks like it is for several .... per this:

LINK:
http://gmpartswiki.com/getpage?pageid=88951

JPG:

Alan 71

Hi Glenn
Here's an example of the core-support with the added block off panels used with the aluminum radiator.
What you have in your photo is for the larger copper radiator.
The support in the plastic wrap looks pretty nice... is it a reproduction?
Regards,
Alan

You can see the panels are just tack welded in place.
Notice also the supports for the aluminum radiator are different than the cradles on yours.
Does the size of the copper radiator to be used determine the position of the cradles?

gleninsandiego

Thanks for the info
Very helpful

So am I correct in assuming the support on my high performance small block is the same as the shroud on a big block?

And this is the support to use when getting the biggest radiator I can?

Also
The saran wrapped surround is the same as the one in the first picture.
It has been sand blasted and powder coated

Glenn

carriljc

The concern I had to address when installing the largest radiator I could squish into my 1968 was the distance between the frame rails. I measured that distance and then got the biggest Summit radiator that would fit between the rails....and I fabricated/modified my own radiator supports. If I can find old link I will add here.

Here is the old info for when I installed my Summit Radiator. If there is one thing that I would be aware of; it is the distance that the rad outlet is above the sway bar. If getting a generic radiator (mine has been wonderful), then get the radiator with the outlet up the highest just for extra room from the sway bar.

Here is the one I installed (had to go look up receipt).
https://www.summitracing.com/parts/sum-380328

And below is my installation commentary:
https://www.corvetteforum.com/forums...post1549031844

Alan 71

Hi Glenn,
You might want to take a look at what DeWitt Radiators has to offer that might suit your future higher hp needs.
Regards,
Alan

gleninsandiego

I just did.
They have some beautiful stuff but it all looks like well over $1000,
which would be a challenge to my budget

69Vett

2 sizes support, 2 sizes radiator, if starting from scratch, install the larger 27.5"version,
for more cooling capacity, cost is nearly the same.

gleninsandiego

It looks like I have the larger one
so I am good to go

Thanks all

0Tom@Dewitt

You can't really say "larger one" as a definition because the overall frame is the same for all three. The base engine small block one for the small aluminum radiator has round pin mounts and that is not in the picture. The option small block one (including L46 and Lt1) is what you have shown which is for the 26" radiator. The big block support is exactly the same except the lower right side mounting bracket is 1.5" further out to the left. I have cut them off and moved them converting many supports from one to the other. The bolt-on upper brackets are the same for the left (driver side) the right side has two different ones. Again, these uppers can be altered as well but they are only about $15 so I'd just buy the right one.

As far as the DeWitts price, you don't need to buy the most expensive option. This one is $550






Product page

gleninsandiego

Thanks Tom, that is extremely helpful and very much appreciated.

So let me come at this from a slightly different way.
I drive in some pretty extreme conditions, ie in the desert when it is well over 100F. I am also going to be adding a vintage air system. And the engine is going to be a 383 cubic inch small block hopefully delivering over 400 hp at the crank.

Given this I am assuming I need as much cooling as possible.
What do I need to get radiator and fan wise?

It appears I will need to mod the support as you stated.

Thanks so much
Glenn in San Diego

terrys6t8roadster

Glen, I ran a Dewitts SBC radiator, the one shown in Tom's picture with a single electric fan mounted in front of radiator in the 6t8 when it had 410 rwhp at the track [Road America] when it was over 85* and the engine temp never went over 180*. Rear end temp reached 310*, should of heard that. It's got a cooler now. T

0Tom@Dewitt

Glenn, I'd try to work without electric fans first. You can always add them later if you really need them. The aluminum radiator is a big upgrade from the copper unit and the copper one was a pretty good radiator to start with. Modifying the core support from a 26" SB to a 27.5" BB isn't worth the time. These two will cool about the same. You can do it if you want to but don't forget that the 69-72 BB uses a separate surge tank and has no filler neck so more stuff is required to complete the conversion.

I would get the HP model with the fatter 1.25" tubes. That would be model 1149070M (assuming manual trans) $679.99. It looks and fits just like the stock unit but cools like a 6 row. That part number isn't loaded on the website but if you want one I can set it up for you.

High HP doesn't (or shouldn't) always mean high heat. Driving a HP car around town uses the same HP as a low power machine. If you push it continuously that's a different story but most often the high HP is just a burst and then we back off.

Andy Tuttle

Clean is much nicer to work on! Are you planning to sandblast and paint or powdercoat the frame? Glad the sombrero isn't compromised! Stay at it!

0Tom@Dewitt

Wrong thread? Two years old