Join Date: Mar 2007
Location: San Antonio, Texas
I have a built Alfa motor that's pretty close to what your are running. I had the same problem with a stock radiator. I cured the problem by have a good radiator shop re-core my stock radiator making a 3 core instead of a 2 core. I run two 8in pusher fans with a stock threaded thermostat. My hot-rod motor now stays cool even in 100 degree stop and go traffic.
Having your radiator re-cored dramatically increases it's cooling capacity. Since the shop simply modified my existing radiator, mounting it wasn't a problem. The extra thickness, however, made it hard to mount my preferred 10in pusher electric fan. Most radiator shops (if you can find an old-school traditional one) will do a re-core for less money than an aluminum race-radiator. The only drawback is that re-cored radiators lack the street-cred of aluminum radiators.
Before you start doing anything major, check your teps with your friend's external tester. When I did that I found that my temp gauge was reading high.
Jim . . . '72 Super 1300, '70, 1750GTV, 2nd series,
'62, Lancia Flaminia Zagato3c, 2nd series