BB Radiators

[Jack Layton]

In 1965 the 396/425 used a special version of the "regular" aluminum radiator nomally seen in the small block cars. In 1966 & 1967 and onward GM changed this to the copper radiator for BB usage except for the L-89/ L-88 cars which once again used the same BB aluminum radiator as seen in the 1965 396/425. Why did GM go to the trouble and expense to have this copper radiator with its different support and other modifications?
If the reason was that it's heat dissipation characteristics were lacking why does it reappear in the L-89? Inquiring minds want to know ! or At least this is a point which has intrigued me. Mr. Hinckley or Mr. DeWitt ??

[Joe L.]

Re: BB Radiators

Jack------

L-89's, either of the 1967, 1968, or 1969 variety, did not use an aluminum radiator. They used the same copper/brass radiators as the L-36, L-68, and L-71 for any given year (67-68 were the same; 69 was different). As far as big blocks go, only 1965 L-78, 1967-69 L-88, and 1971 ZR-2 used the wide-core aluminum radiators.

In 1965 GM appeared to be heading in the direction of aluminum radiators for both big block and small block Corvettes. But, they "changed direction" for most big blocks starting in 1966. I don't know why, though. Obviously, they had great confidence in the wide-core aluminum radiator since they used it through 1971 on HD applications. Plus, the basic design was well-proven for 63-72 small blocks. I expect that cost was somehow a major factor in the decision to phase out the aluminum radiators. After 1972, aluminum radiators were not used in Corvettes again until new-technology (and far less expensive to manufacture)aluminum radiators appeared for the 1984 model year. Corvettes have used them ever since.

[Jack Layton]

Re: BB Radiators

Hence, the question remains on the table. I wonder if Mr. DeWitt has a comparison on the heat dissipating capacity between the aluminum radiator for the 1965 396/425 and the copper radiator of the 1966 427/425. I have wondered if the copper radiator was less efficient than the aluminum radiator. My 1965 396/425 always ran very cool ( 180 ) even in the most hot and humid days of summer. Yet I often hear folks complain about how hot their big block runs with most of them owning 1966 or 1967 cars.

[Joe L.]

Re: BB Radiators

Jack-----

A lot of the thermal info on these radiators can be found on the DeWitt's web-site at www.dewitts.com

I think that the GM #3007436 aluminum radiator had the greatest cooling capacity of any radiator ever installed in a Corvette.