1969 350/350 no a/c 4 spd Radiator/Hose

[Hugh P.]

I am looking at a 1969 Corvette that appears to be well preserved but have questions regarding the radiator and hoses. I can read (see attachment) the upper hose p/n 3946852. According to the judging manual this is the hose for 350 with copper radiator and 350 4spd should have an aluminum radiator and 3935466 upper hose. Also the shrould (from the photo) does not appear to be metal per judging guide but the shroud looks fibreglass. Also, I can't tell from the photo, but if no overflow tank does that mean the radiator is probably copper and remainder of parts have been converted and no overflow tank is required? Except for judging and correctness, and it drives ok is there any risk to leaving as is?

I will be looking at this car later this week, so all I have are photos for now, What would be the correct p/n for the radiator, and will it be visible without removing anything?? Also, does the A.I.R pump look correct in the photo?

[Kenneth H.]

Re: 1969 350/350 no a/c 4 spd Radiator/Hose

The photo appears to show a copper radiator. The radiator was made by Harrison and can be found on the passanger side tank. Look for any mounting holes in the fender skirt to see if a aluminum tank was installed. Also look at the radiator mount bolt heads to see if they show signs of being removed. There have been 1969 corvettes judged having a copper radiator installed in a 350/350, 4-speed, with non-A/C. There are also numbers on the driver side on the fiberglass shroud. In addition, take a look at the radiator cap. If the radiator is copper, then it should have an RC-15 cap. If everything looks to be original and appears to have not been removed and changed, it is possible that the configuration is correct and should be left as is to be documented by the 68/69 Judging Reference Manual revision team. Hope this helps. If you need more info, contact Paul Oslansky. He is a great chassis judge and this would fall under his knowledge.

As for the smog pump, it is hard to tell from the photo the finish. It should look as if it was removed from the casting and not have the appearance of being bead blasted. There is a date as well, but hard to read when the pump is installed.

[Terry M.]

Re: 1969 350/350 no a/c 4 spd Radiator/Hose

Hugh,

Ken has the right story, but I will add that the top crossbar on that copper radiator does not appear to be TFP (Typical Factory Production). I would expect the upper surface of the cross bar (it might be called a spreader bar) to not be so wide, and the rectangular holes (actually one should be rectangular and one square) should be a different configuration.

This may only mean that the radiator has been replaced/re-cored, but if that is the case the original bar was not retained. Of course one should look carefully at the clues Ken gave because it also may indicate a change from aluminum to copper radiator.

The fiberglass shroud shown is correct configuration for the copper/brass radiator. I don't have my reference material at hand, but the shroud number on the driver's side is well documented as this shroud was used extensively in the 1968-1972 time period. This shroud should have an extension (semi-circular piece about 2 to 3 inches wide) on the bottom of the fan opening. Check to see that it is there. It is often discarded when radiator work is performed -- like the ignition shielding and other "nuisance" parts.

[Paul O.]

Re: 1969 350/350 no a/c 4 spd Radiator/Hose

Hugh

As Ken and Terry there are many items to check that can give you a better perspective if the radiator is original or has been worked on.

First let me give an answer to some of your questions .

1. The radiator hose P/N 3946852 is typical for a copper radiator for a 350/350 no A/C car. The tower clamps were used till around Sept 1969 if that fits good.

2. With the copper Radiator the shroud should be of a natural finish fiberglass reinforced plastic last 3 digits of P/N 109.

3. As Ken stated the radiator cap for the copper radiator should be an RC-15 with a flat center rivet with a small raised ring at the edge of the rivet.

I then downloaded and enlarged the photo from what I can see the radiators finish looks to be very good which could indicate it has been re-cored or rebuilt I do see the first rectangular hole in the cross bar but as Terry has noted the core seems very wide. As Ken said look on the right side of the radiator tank it should have the word Harrison plus about half way down the tank where it meets the core there there should be a metal tag in most cases it would have 2 larger letters MK and a P/N. The next item the water pump is a later service replacement style. The shrouds extension the rear lower section of the shroud appears to be there there are 3 bolts holding that into place they were originally hex-recessed head silver finish.

So as a quick answer the copper radiator was used in 1969 350/350 engines with a fiberglass shroud and with that radiator hose. Now you have some investigating to do for a better determination of the facts.

As for the smog pump there in the photo a raised block on the pump that appears to be touching the smog hose but is not on the back side is the date. You need a small mirror to view it. Code is DDDYSM Julian date, year, shift and model.


Paul 18046

[Hugh P.]

Re: 1969 350/350 no a/c 4 spd Radiator/Hose

Thanks all for prompt replies. Attached are 2 more detailed photos. I hope this helps. The car is well preserved 1 owner and only 20,000 miles.
Mid-January 1969 build. Not sure about the upper support bracket, but all sugestions will help. Otherwise appears to be a true survivor.

[Terry M.]

Re: 1969 350/350 no a/c 4 spd Radiator/Hose

More to like and more to check.

Looking closer at the first picture in your previous post I see the one end of the shroud extension, and Paul nailed the water pump I missed. For a January 1969 car you should have tower clamps on the radiator hoses, as Paul mentioned. Looking closer it looks like the water pump is a slightly different color than the intake, but you will have to look closely at the engine paint to see if it has been refinished. Sometimes people get carried away when they have paint in their hands. I hope not in this case.

On your first picture on this post I can see one of the screws for the shroud extension on this end, so it looks like the extension is there. Those screws often sheer off on removal (ask me how I know ) so check for three matching hex heads. They might be hard to see given their location inside the shroud.

Paul aren’t the heads of the extension screws supposed to be on the outside of the shroud??

Still on the first picture on this post -- I like the MK tag on the radiator. It does look like the front end has been aligned -- the shinier of those shims is not TFP.

In the second picture this post: too bad the rad cap is out of focus, but what can be seen in silhouette looks good. Check the details Paul mentioned. When the radiator is worked on (and there are enough clues here to say that it has) it is not uncommon to replace the rad cap even if that is not necessary.

If this is a one owner car the owner (if the is on the green side of the grass) should be able to fill in the blanks on some of these points if gently prompted -- unless he has a terminal case of NCRS disease. Just be gentle with him. Honey will get you a lot farther than vinegar and keep in mind that original owners often have selective memory.

[Paul O.]

Re: 1969 350/350 no a/c 4 spd Radiator/Hose

Terry

On the extension the 2 upper or side fasteners the head is on the inside of the shroud only the bottom has the head on the outside.

Hugh

Great photos need a clearer photo of radiator cap but it does appear to be an original RC-15. Nut sure which bracket you are looking at. As Terry pointed out the alignment shims other then the shinny one look to be originals. Also the upper control arm bushings look original plus I like the nut and lock washer holding the a-arm shaft to the frame. I can just make out the Harrison stamping on the tank RT side.

If you have time could you post a photo of the air cleaner showing the hose from the base to the RT side valve cover. It is part of a survey on how that tube on the base is pointing. Looks like a very nice car.

Paul 18046

[Jim M.]

Re: 1969 350/350 no a/c 4 spd Radiator/Hose

I was wondering about the insulation on the underside of the hood. I was under the impression that an early build 69 350 would not have sound insulation?

[Terry M.]

Re: 1969 350/350 no a/c 4 spd Radiator/Hose

I was wondering about the insulation on the underside of the hood. I was under the impression that an early build 69 350 would not have sound insulation?

My belief is some had the insulation and some didn't. While I have not attempted to start a survey on the subject, My perception is that there is no rhyme or reason to which engine option or build date got the hood insulation and which didn't.

There is another research project waiting here if someone has the time and enthusiasm.

[Jim M.]

Re: 1969 350/350 no a/c 4 spd Radiator/Hose

That's pretty much my perception as well other then I was thinking that the insulation was found mostly on the big block cars. My early in January build 69 L-46 didn't have the insulation. It would be interesting to find out someday what the thinking was at the time to put insulation on some and others not.