Max cooling 454 or 6.2 rad?

[Ned Kelly]

Which factory rad would provide the best cooling capacity? I'm currently running a 454 rad with my BBC but it's 20yrs old and it's looking like time to replace it.

 

[76zimmer]

If your looking at replacements Ned. check this out I just went through all that this summer....

http://coloradok5.com/forums/showthread.php?t=261694&page=17


POST 843...

 

[Ned Kelly]

Zim,now I recall following that for awhile in the summer, I just did not remember where to find it. Good info. I'll give it a thorough read tonight. Thanks.

 

[nvrenuf]

Are you running electric fans or a fan & clutch? If a fan and clutch then make sure you have a 7 blade fan and severe duty clutch. For the severe duty clutch you buy one for an 83 K30 dually w/ 454 AND 4.56 GEARS. The gearing option makes a difference, if the parts place doesn't offer a different part # for that application go somewhere else.

That said I have a 454 with the big 6.2 rad, 7 blade fan and severe duty clutch and it stays dead on 190*, if not below (I'm using a 195* t-stat).

 

[Ned Kelly]

I'm running an old school direct drive 7 blade fan. I will consider the fan clutch upgrade (good advice), or do the Windstar electric fans when I change the rad. How are the inlet and outlets on the 6.2 rad? Do you recall what uppper/lower rad hoses you used to mate the 6.2 rad to the 454?

 

[nvrenuf]

I had the upper neck cut off and changed to the 454 hose size and used a OE 454 hose.

The lower neck is huge so I cut about 3" off the water pump end of a 454 hose, slid it onto the pump and then used the 6.2 hose which fit over the bushing perfectly. Everything fit nice and tight with no leaks.

I probably would have had a new, correct size lower neck put on too but the rad shop was bitching about the age of the rad and such so I did the minimal and had it cleaned and the one neck done. It was an extremely clean low mileage rad from a CUCV so, imo, it was fine. I think he just wanted to try and sell a rad.

 

[Russell]

6.2L rad is quite a bit larger than a 454 rad. That said, a new 4 core big block rad will probably keep you cooled!

 

[Ned Kelly]

Ok I got a 6.2 rad that looks good. I'll take it to the rad shop for a cleaning and modify the upper outlet. I"ll do as per your directions below. Did you use the 6.2 factory shroud? Thanks in advance.

I had the upper neck cut off and changed to the 454 hose size and used a OE 454 hose.

The lower neck is huge so I cut about 3" off the water pump end of a 454 hose, slid it onto the pump and then used the 6.2 hose which fit over the bushing perfectly. Everything fit nice and tight with no leaks.

I probably would have had a new, correct size lower neck put on too but the rad shop was bitching about the age of the rad and such so I did the minimal and had it cleaned and the one neck done. It was an extremely clean low mileage rad from a CUCV so, imo, it was fine. I think he just wanted to try and sell a rad.

 

[nvrenuf]

Yeah, everything I have (rad, shroud, upper brackets) came from a 6.2 CUCV.

 

[Ned Kelly]

I got the upper brackets too. Ok, looks like my truck will be back on the road soon!
Thanks again for the helpful info.