Use only 10,000 rpm flexfans , 8000 minumum , and dont total time ur engine under the hood. Definitly dont use a plastic or fiber fan !
I have a practically new 10,000 and 8000 setting on the bench , just one of the experiments I tried when trying to keep my 440/505 cool in 90 plus heat.
Running a short clutch factory steel 17'' fan now , dont think it pulls any more air than the flax fan ,but its what I wound up with . I tune/set my timing from the drivers seat , so a flex fan doesnt bother me at all----------
