Pic of diesel rad hooked up to gas application?

[Ned Kelly]

Time to replace the rad on for my 454 K30. The OEM BBC rad served well for 20yrs but it's not able to keep up anymore, and add to that the odd intermittent leak here and there.

Anyone have a few pics of the bigger diesel rad hooked up for a gas engine application? Particularly the hoses and inlet/outlet mods ....on a BBC would be nice too. I think I may go for the bigger rad so just wanted to see the mods required. Thanks.

 

[nvrenuf]

I put a diesel rad in my 91 K5 with a 454, I thought I had some pics in my build thread but I don't.

If you have a 81+ truck it should be a straight forward bolt in as I believe all 81+ core supports have the extra threaded holes on the drivers side to accept the upper bracket. My swap was done using the rad, upper brackets and shroud from a donor CUCV.

Upper hose - I used a 454 hose but had to change the neck on the rad. The 6.2 hose is too big on the engine side so I opt'd for the 454 hose since the rad tank neck change was all that was needed to make it work.

Lower hose - This took both part of a 454 & a complete 6.2 hose to make it work. I cut the top 3" off of the 454 hose and used it as a bushing on the water pump neck. This bushing made a perfect fit for the 6.2 hose and does not leak (single hose clamp, not sealers etc).

The mounting bushings are still available from GM from about $6~$8 each (I believe they're the same as a gas 4 core rad).

For the fan I used an OE 7 blade with a HD fan clutch. I have found the best fan clutch to be from an 83 K30 w/ 454 and 4.56 gears - the gear ratio does make a difference. I also use a 192° thermostat.

This set up work flawlessly on the K5 and never gets over 195° regardless of idling or driving.

 

[Ned Kelly]

Nvrenuf,
Thanks for the descriptive answer covering all the details. I don't need pictures now! I have an '85 K30 and I see the extra upper and lower core supports you speak of.

Sounds like an easy enough swap. Did you plumb your 454 to the integral engine oil cooler on this rad also?
Thanks again for the good info.

 

[nvrenuf]

No, I didn't try to use the oil cooler since it was on the opposite side. I actually tried to find some plugs to cleanly cap it off but never could find any.

It was a very easy swap once I got the upper hose neck swapped.

 

[Ned Kelly]

Ok, I'm going to do it. Thanks again.