When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
I just finished the install my 427 into my original small block 72. My question is about the radiator. My car was a no ac manual car so I have a dewitts aluminum radiator with their fan combo. I drove the car today and the temps were around 210. Now it was a cool day with temps in the 60’s. Just curious if this will work or not in the summer.
Thanks
Joey
Last edited by Joe79Vette; Oct 25, 2019 at 09:22 PM.
Front spoiler on? Radiator seals? Looks like new radiator hoses? Bottom one have the spring in it? Temp gauge accurate?
Yes to all of those. I am just wondering if a small block radiator can keep a big block cool. My small block never got above 190 even sitting it traffic in the summer.
2020 Corvette of the Year Finalist (performance mods)
2019 C3 of Year Winner (performance mods)
2016 C3 of Year Finalist
You alresdy answeered your own question, 190* in the summer and 210* in 60* weather, find yourself a big block radiator now or you will be in the summer. Its not going to be worth the hassle this summer. You might be fine on the highway at low rpm and that is a big "might be". I seriously doubt it and you'll fry your motor in stop in go traffic.
Last edited by Rescue Rogers; Oct 26, 2019 at 08:13 AM.
I'd like to know which model SB radiator you are using. I see the surge tank, so is this the smaller 22.5 wide? What are you running for coolant? Ratio? Someone already asked, but are are you sure 210 is 210?
I'd like to know which model SB radiator you are using. I see the surge tank, so is this the smaller 22.5 wide? What are you running for coolant? Ratio? Someone already asked, but are are you sure 210 is 210?
Tom,
I am using your 4239063M fan combo. I am using 50/50 Peak antifreeze. I am going to using my temp gun to make sure it is correct. I know the gauge is and it was right on with the small block. Will your 4239026M work with my pins in my current small block support and also cool better then what I currently have?
BB's run hot. My 69 BB runs about the same temp as yours with my stock radiator and clutch fan. The cramped engine compartment, laid back radiator, lack of ventilation, etc., doesn't help. Different stats don't make any difference. The temp will go up when stopped on a hot day, but drops once I get going. Other wise, it run about the same temp in the 50-100 temps here in SoCal.
Will a bigger radiator help? I don't know. I'd wait and see when it warms up.
This is one reason that I use synthetic oil with it's higher temp rating.
I have my timing at 32 at 2500 rpm. I may just wait and see before I change it out. This may involve a new radiator support as well if I go to a new BB radiator.
Tom,
I am using your 4239063M fan combo. I am using 50/50 Peak antifreeze. I am going to using my temp gun to make sure it is correct. I know the gauge is and it was right on with the small block. Will your 4239026M work with my pins in my current small block support and also cool better then what I currently have?
The 26M would fit and cool better but I'm not convinced you need to go there yet. A couple more questions....When you say 210 on a 60 degree day, what speeds are you driving. What I would like to know is idle and under 30 mph versus highway speed. I do not believe in the theory that big engines or big HP for that matter mean that the motor has to run hot. I have a 2016 Z06 (650 HP) that runs the same temperature no matter what the outside temperature is. Why? Because I never pull 650 HP and neither are you just driving around town.
If you used a different temperature sending unit when you switched engines, the gauge may not provide the same reading as before. Replacement switches are notorious for reading high if they exceed 180. Either re-check this new one or put the old one back in. High temperature at idle is usually the engine timing and ignition mapping. High speed problems are usually radiator deficiency.
I have the Dewitts small block (with ac) radiator in my 71' with a 700hp iron head big block and it never runs over 195*, in the middle of a 95* day with the AC on full blast. On average, I run 185* at cruise or at idle with the AC on, on a humid, 95* day. My point is the Dewitts SB radiator that fits the 71-72' core support is plenty. (27" core). If its running 210* on a 60* day, going down the road, then you have something else going on. I run a 160* thermostat, and on a 60* day it will sit right on the thermostat at cruise...160* all day long.
I'd be looking closely at the timing, thermostat, water pump, and even the fan clutch.. etc etc.... Your combo with the 180* stat should be running no more then 190* at cruise, especially on a 60* day.
I'd go in this order:
1) Verify the temp with IR gun or a good mechanical gauge
2) Verify the thermostat is opening at the correct temp and opening fully.
3) Verify timing and vacuum advance operation. Definitely run at least 15* of initial timing...more if you can squeeze it and still keep your total timing at 36* or so.
4) Check water pump, lower radiator hose, core support seals, lower air damn, fan clutch
5) Also, if you are running stock manifolds with the heat riser, make sure the riser is functioning properly and not stuck partially closed.
Yes to all of those. I am just wondering if a small block radiator can keep a big block cool. My small block never got above 190 even sitting it traffic in the summer.
Mine does. I have a zz502 and am cooling it with an original copper/brass 1969 small block radiator. It's never gone above 190, even in traffic on a 90* day.
I am going to take it out tomorrow to verify the temps. It is a new rebuild and I want to make sure there is no air in the system as well. It is to be about 70 tomorrow. I will do some highway and also around town driving to see if there is a difference. I double checked the timing and it is good.
Thanks for all the advise and help. I will update tomorrow.
The PO swapped a 454 motor into my 68 convert that was originally a small block car. He also installed a champion aluminum radiator with four rows of tubes and an electric fan that he had wired to run all the time whenever the ignition key was on. He also kept the stock belt-driven fan. I added a relay to turn on the fan at 180 degrees, 180 degree high-flow thermostat, removed the belt-driven fan and the fan shroud for the belt-driven fan. The car runs at about 180 when at road speed, even in 90 degree weather. In stopped traffic the temp sometimes climbs to about 200 degrees if the outside temp is in the 90s and if I sit stopped for 10-15 minutes. Most improvement will be shown by increasing the rows of cooling tubes and making sure you have a decent electric fan. If you need to keep the stock belt-driven fan and do not add an electric fan, make sure all of your radiator shrouds and gaskets funnel the air thru the radiator and not around it.
Cooling a Big Block
