over heating issues during break in

[j.rigby15r]

So here is were I am at. I just rebuilt a sbc 350 in my 64 c10. It has a small rv cam, edelbrock intake and carb, clutch fan, no shroud, and the stock 3 core 25"x17" radiator. My buddy and I were starting to break in my cam and motor and had to shut it down because the radiator cap started spewing coolant, ( I forgot to put the new one on). It was about 230-240 in temp after about 10 min of run time. it was about 65-70 degrees outside. we let it cool for about an hour and got a better temp gauge. After letting it cool we started it up again and after about 5 min it was back up to aprox 240 so we shut it back down. It dieseled a bit after killing it. I am trying to find a fan shroud, most of which I can find are $150 plus. Any recommendations on a fan? I've been looking at these

http://www.summitracing.com/parts/opg-ch26693/overview/

http://www.classicindustries.com/pro...ts/z40020.html

Any thoughts on fan shrouds or on heating issues, as well as breaking in issues.