How much radiator do I need?

I'm running an open hood on my 39 Chevy truck with a dual quad 425 nailhead and an old Farmall tractor grill shell. The shell is only 20" tall x 16" wide so it is limiting the size of radiator that will fit. I have found a supplier who has tractor radiators in stock with the correct dimensions and outlet placements, but the core is only 2" thick with three rows of straight fins. The radiator guy didn't know if it would cool it. He said that the radiator was designed for a tractor with 35 HP. I'm probably running 375 HP or so...He said it would hold about 1 gallon of coolant. I'm guessing that the block carries another gallon or two...Any ideas if this will work or will I need to go four rows? Many thanks!

 

Probably not, and tractor grills belong on tractors.

 

I read in a post here somewhere that the radiator should have the same or more cubic inches than the engine.

 

Speedcity,
There is a formula for this, but I can't remember where I saw it... some hot rod mag. A simple web search will probably get you to the facts. But probably the best thing is to call up a place that builds hot rod radiators and get some advice on square inches, fan rates, etc. This isn't an area of your build you should be guessing about. I know the Walker Cobra and 2000 CFM fan in my 37 Ford are adequate for a stock 5.0 Ford because I did the math / got the advice first.

I drive my car any time, any place and never worry about it. I don't think there should be any reason in this day and age to drive around with one eye on the water temp gauge and one finger posed over your manual switch for your electical cooling fan. Put the fan on a thermostadt, have the right fan and core and you are living free and easy.

The only problem I've ever had is a bad power plug to my electrical fan, which did cause it the motor to overheat in summer traffic. Since that fix... I'm back to good to go. Gary

 

I'm using a Walker Cobra Z series and 2,700 cfm electric fan on my dual quad 401...had it out last weekend in 90 degree weather and it never went above 180 (the car is a hoodless '33 Ford coupe).

 

based on your info you need a 4-row or a 3-row high efficency at the least preferably with an engine driven fan blade and proper shroud

got a local radiator shop nearby and an old-timer that knows what he's doing?... do you have the original tractor radiator? if so they should be able to order a custom core and relocate the water inlets and outlets for you.

be warned though... copper/brass won't be cheap but if you want it to cool properly your going to have to spend some $$

(i work at a radiator shop)