BB Radiator for SB?

[1974vette]

My 74 smallblock (somewhat built) runs rather hot, i think around 245-250 in this "spring" weather that we're having now. Its not really hot outside. In the summer, it gets up around 100 though. I replaced the radiator last april. I was wondering, could you use a big block radiator for the smallblock and it work properly? What are the ups and downs of this?
-Matt

 

[Stallion]

Matt, I don't know what would happen if you put in a BB radiator, but if I were you I would first try to solve your overheating problem. In the spring (I imagine your spring is like Jersey's spring) you should not be running that hot. Maybe you tstat is stuck?

I personally would try to fix the problem instead of installing something to override the problem. But thats just my $0.02.

Stallion

 

[80convertible]

I think you have other issues. I lived in Charlotte, NC for the last 6 years and never had an overheating problem with my smallblock...even in the dead of summer sitting at idle in traffic. A properly functioning cooling system should cool your car where you live. I thought I had an overheating problem one summer only to find out the previous owner had installed an incorrect temperature sending unit which was reading high. Besides all the things like thermostat, hoses etc... you could have blocked passages in the engine due to age.

 

[Jack]

My 74 smallblock (somewhat built) runs rather hot, i think around 245-250 in this "spring" weather that we're having now. Its not really hot outside. In the summer, it gets up around 100 though. I replaced the radiator last april. I was wondering, could you use a big block radiator for the smallblock and it work properly? What are the ups and downs of this?
-Matt

I agree with the others ... a bigger radiator probably ain't gonna do it ... UNLESS you're making a lotta HP now. How many rows does your recently replaced radiator have ?... 2 or 3 or 4? Automatic trans or 4-speed manual? Are you sure it's too hot? ... is your in-dash temp gage the sole indicator? ... 30 year old gages and sending units are notoriously inaccurate/faulty. 80 convertible is so right about incorrect sending unit ... most local parts houses do NOT have the right one ... it may look same but reads wrong. Replacing t'stat AND rad cap is good first move. If yours has an overflow tank/bottle ... make sure the hose from rad to it is not cracked, leaking, collapsed or kinked ... and that the bottle's coolant both rises and falls as motor heats and then cools down. Verify that bottom radiator hose has an inner support wire and is not collapsing while running ... water pump can & will suck a bottom hose nearly shut. Another thing to consider is whether the fan clutch is OK. If ignition timing is incorrect that'll often cause overheating ... same goes for too-lean carb (fuel:air) mixture. But first things first ... make certain you're not losing any coolant anywhere ... even through a head gasket ... verify no coolant lost. Also verify that it is really too hot ... that may require use of a "known good" gage w/sending unit or thermometer to verify temps.

FYI, a BB rad will fit ... but many who upgrade rads go to aluminum. BTW, those who may've noted earlier threads where I found 31" X 19" "Northern" two row aluminum rads are cheap ($170) at speedway motors ... I've just found em even cheaper ($157.50) at Motorville in KC, KS (1-888-463-0482). Their 28" X 19" is $150. Motorville is also very competitive on certain Flex-a-lite fans ... they have the twin-puller P/N 295 @$338.10. For $80, they have a brand new asian knockoff of an edelbrock performer intake P/N 2101 ... I think 2101 is currently about $130 at Summit/Jegs.
JACK:gap

edit ... correction ... I goofed ... motorville toll-free prefix is 888 ... NOT 800.

 

[80convertible]

I would verify the temp before doing anything else. When I was swapping heads I had to use a mechanical temp gauge temporarily. Drain your coolant and install the sensor to the mechanical gauge where you factory sensor goes. This will allow you to verify your temp. An aftermarket temp gauge from Autozone cost about $25.00. It's worth it. Now you will know for sure if you have an overheating issue. While you have the factory temp sensor out, you can verify it's correct for your year. Unless it is new, I would replace it. Use a AC/Delco replacement unit...not aftermarket. The sensor is calibrated to a specific resistance for your year gauge. An incorrect sensor will have different resistance and cause error on your gauge.

If you do have an overheat problem, work from easiest and least expensive to more complex. The worst is to spend lots of time and $$$ only to find out is was a simple and cheap fix. Keep us posted of your progress.

 

[1974vette]

thanks for all of the responses and suggestions! i'll have to check these out.

 

[Paranoid]

I just went thru a radiator search last week. 1973-76 used the same radiator, and in fact one of the largest in a Vette. 27.5in x 17in core. I know because it turns out I have one in my '70 using a SB radiator support! :L Must be in 1973 GM wised up and used one large radiator and one core support for BB's & SB's.

 

[Robin7TFour]

HELLO, since we all seem to agree that 30 year old gauges are somewhat suspect in accuracy. i installed and extra sensor in the opposite head. i used the sensor from a late 70's chevy that uses a light for warning. i feel it's a cheap way of backing up the gauge. so if the light comes on,i KNOW the car is overheating,

my 02

ROBIN