305-400 SBC swap - Radiator Question

[TxSam]

Hi guys! Lurker here, but in the middle of a 305 to 400 sbc swap in and '83 K10. The stock radiator has some small leaks so we decided to get them addressed while swapping. Local shop wants $190 to unsolder one of the tanks(where the leak is)and rod it out and resolder. It's a brass/copper unit so it's decent quality. My question is would it be better to get a new, all-aluminum unit instead of sinking the $190 into this unit. I'm a little concerned about cooling capacity since we are jumping up to the 400. It has aluminum heads with steam holes drilled. What do you guys think?

On Edit: Other than daily driving, we won't be doing any towing and only light off-roading.

 

[Charlie]

 

[4WDKC]

You can never have to much cooling with a 400, that being said I would be tempted to look at larger radiators than what came with the 305.

 

[Camar068]

If I was going to spend that much, I would just do the radiator upgrade below. Oil cooling would be a plus as well.

https://www.gmsquarebody.com/threads/upgrade-installing-the-longer-2wd-3-4-ton-454-radiator.15474/

 

[Snoots]

2 or 3 core?

I'd fix a 3 core.

But that's just me.

 

[TxSam]

Thanks for all the input! Going to try to decide something today.

 

[Rusty Nail]

I don't know...but I feel an original copper/brass unit will have a better cooling potential than a bigger aluminum unit and think that may be a wash , in reality.
Sounds like a big pain in the ass for nothin , to me.
Again, I don't know, but those were some of my thoughts regarding.
Based upon your description of the intended use, I do not believe that a fresh 400 has any greater need for improved cooling than a 305 would..did the old engine used to run hot in the truck or no?
Did 400s ever come factory equipped with larger radiators than 305s?

See where i'm headed with all this?

 

[Snoots]

Get a Flowmaster water pump.

 

[peats]

treat it as a big block and put a 4 row rad in. why skimp on such an important part?

 

[1973c10]

treat it as a big block and put a 4 row rad in. why skimp on such an important part?

 

[4WDKC]

I don't know...but I feel an original copper/brass unit will have a better cooling potential than a bigger aluminum unit and think that may be a wash , in reality.
Sounds like a big pain in the ass for nothin , to me.
Again, I don't know, but those were some of my thoughts regarding.
Based upon your description of the intended use, I do not believe that a fresh 400 has any greater need for improved cooling than a 305 would..did the old engine used to run hot in the truck or no?
Did 400s ever come factory equipped with larger radiators than 305s?

See where i'm headed with all this?

That depends on how it is built, the stock radiator in my 79 vette couldnt handle the 406 in it before I got it. The PO changed it out to a brass 4 core and it still overheated on him. Since buying the car I have swapped to a core alum radiator and it is better but still not right.

 

[Best truck design]

I to

I don't know...but I feel an original copper/brass unit will have a better cooling potential than a bigger aluminum unit and think that may be a wash , in reality.
Sounds like a big pain in the ass for nothin , to me.
Again, I don't know, but those were some of my thoughts regarding.
Based upon your description of the intended use, I do not believe that a fresh 400 has any greater need for improved cooling than a 305 would..did the old engine used to run hot in the truck or no?
Did 400s ever come factory equipped with larger radiators than 305s?

I totally agree. As long as you can keep the brass aluminum rad I would.

 

[75gmck25]

I used a Jegs Champion 3 row aluminum in my truck and have been very impressed by its cooling capacity. My stock 3 row was okay, but there were a few time the temps got up to the 215+ range when running A/C in traffic. With the new aluminum radiator I've never seen it above about 200, even when idling with the A/C on.

I'm also using a Stewart Stage One high flow water pump and 195 degree high flow thermostat. I have a stock steel fan, shroud, and HD fan clutch. The overall temps are incredibly stable under all conditions.

I replaced the old radiator because I accidently punched a hole in it, but it turned out that the aluminum was great upgrade.

Bruce