I just swapped in a new engine (383, 10.5 CR, 450-500hp), and I don't think the stock single fan is cutting it. I have a 170* thermostat, 195* on 185* off fan switch, big 31x19 griffin radiator, about 75/25 coolant mix with water wetter, stewart stage 2 waterpump, all new stuff. However, the fan will kick on and just not cool the new radiator. I am still using the stock guage so I don't know how acurate it is but this thing will get to 220 and never come down.

I'm looking at these two fans from summit, and wondering what everyone thinks.

http://store.summitracing.com/partde...5&autoview=sku

and

http://store.summitracing.com/partde...5&autoview=sku


The main differences are the cfm ratings as well as the amps. The flex a lite fans flows 2500 @ 20 amps and the derale fans flow 4000 cfm @ 50 amps.

If I went with the 50 amp fans would I have to upgrade my alternator? I have a stock replacement for an LG4 right now. Battery?

Thanks.

 

im running dual Thermo fans ATM rated around 2,700CFM and i only use one 80% of the time but if i have them both engaged when they switch on there is a masive kick in the volt guage and at idle you will feel the revs drop from the alts extra load.
But when they both come on at 190'F they are only on for 1min (less if im moveing) then they hit there shutoff temp of 180'F. (work EXTREMLY well on my basicly stock 305).