I have a 67 SS/RS came stock with a 396, however previous owners have change the motor to a 350. I want to buy a new radiator, this one doesnt cut it. I found that radiators (bolt spacing) were larger/wider on the big blocks. When I measured the radiator support bolt spacing it measured for a short block ( the present one) . However, there are a second set of holes that are wider , which I think matched the dimensions for the big block.. Is the only difference between a short block radiation and a big block the mounting holes, I meant the hole for the radiator wouldnt be bigger for the big block or the small block that is a fixed dimension. Just there are two sets of holes, can somone tell me if the actual size fo the radiator is difference or just the mounting holes?

I want to buy a new radiator, this one doesnt cut it.
Sent it to a radiator shop to have the tanks pulled and cores cleaned?

I think by your description you are correct in your assumption about the difference in radiators.

If you aren't a stickler for exacting parts, I would recommend an aftermarket aluminum radiator. There are a couple of manufacturers that even match the factory stamped tank look. And, moreover quality aluminum radiators will out perform any old age copper model by a long shot.

The core of the big block radiator is about two inches wider than the small block, and it had four rows of half inch tubes rather than three rows.

When talking about a radiator we are talking about surface area. Bigger is better. The Harrison radiator is bigger and heavier in the big block version than the small block.

The advantage the aluminum radiator has over the brass one is surface area. Because aluminum is stronger than brass they can make the tubes bigger. Bigger tubes means more area, so it sheds heat faster, even though copper is a better conductor than aluminum (brass isn't) the increased area more than compensates. Additionally aluminum is not only stronger than brass but it is much lighter, even going to a big block radiator which is bigger over all it would be lighter than your old brass small block radiator.


Larger Dave

I am going with an aluminum radiator.. dont care if stock look just want to know if the big block and small block core area will fit in the shorud/support opening.

Use a shroud.

I am going with an aluminum radiator.. dont care if stock look just want to know if the big block and small block core area will fit in the shorud/support opening.

SMALL BLOCK RAD 20.75 X 17.0

BIG BLOCK AND SMALL BLOCK WITH A/C 23.0 X 17.0
Your core support will accept the bigger rad you will have to buy a new fan shroud .
check this link for a CORRECT FIT UNIT

https://secure.wf-api.com/www.chevellecooling.com/46.html?psid=aMZiIDm.pcKk6nEX5M8d&sm=8856

Don

Just replaced my radiator this weekend. I have a 69 and it too had extra holes about 2 inches away from the existing radiator bolts. I got a Griffin big block for the 67-69 models and it was a direct fit. The extra holes I guess are for the big block radiator. Anyway in my case they lined up perfectly. It only lightened my wallet by 399.00.

Only problem I had was getting the transmission lines to stop leaking when attached the radiator. Several trips to the parts house took care of that though.

Oh I had to cut some of the mounting bracket away on the left side of the radiator (as you face the car) to make room for the battery holder and one of my transmision cooler lines.

I use a black magic electric fan to pull air across the fins and it seems to work great for my application.

Overall I am very happy with the performance and the drop in water temperature.

Good luck,

Stonekold69