SBC to BBC Radiator Swap Questions

[busterswt]

Recently picked up a Spectra B730 radiator (2.25" core) to replace the tired factory radiator (~1.25") in my '91 V2500 Suburban w/ 350. I didn't think about it at the time of the order, but later came to find that the upper and lower isolator bushings and upper mounting brackets were different between the SBC radiator and what likely turned out to be the BBC radiator.

Anyway, I picked up some new L/R mounting brackets and bushings from Auto Metal Direct and came to find that they were likely meant for the wider (diesel?) radiator and were meant to connect to filler panel, while the 730 would've used a one-piece filler with integrated brackets. Those two brackets do work, and with a slight modification to the SBC shroud it seems like a usable setup. The shroud sits a little further back and the fan doesn't quite have a 50/50 split anymore, and the shift exposes a gap between the core support and the radiator. Haven't quite figured out how to fill the gap in a way that looks less DIY and more 'factory'.

Is this enough of a gap to cause any concern?

I'm also curious if the one piece filler/bracket will work with the SBC shroud without too much fuss.

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[Ricko1966]

how wide is the gap? Does the radiator actually fill the rubber bushing? Or is there room there to cut,relocate and shim the bushing to pull the radiator tighter to the core support?

 

[nvrenuf]

Real problems with gaps are related to openings between the shroud and radiator allowing the fan to pull air around the radiator instead of through it.

The top piece you’re missing is just a plastic cover that spans the area between the metal mounts. Diesel and gas radiators are different widths so be sure the cover is correct for width.

The gap isn’t quite that big but for years Toyota has put a long piece of square foam (picture 1.5x1.5xlength) in the gaps between the radiator and core support.

 

[busterswt]

how wide is the gap? Does the radiator actually fill the rubber bushing? Or is there room there to cut,relocate and shim the bushing to pull the radiator tighter to the core support?

The gap from the radiator to the top of the core support is one inch (1"). The radiator fills the bushings completely, and I suspect this isn't an issue when the big block filler panel w/ integrated brackets and fan shroud are used.

Real problems with gaps are related to openings between the shroud and radiator allowing the fan to pull air around the radiator instead of through it.

The top piece you’re missing is just a plastic cover that spans the area between the metal mounts. Diesel and gas radiators are different widths so be sure the cover is correct for width.

The gap isn’t quite that big but for years Toyota has put a long piece of square foam (picture 1.5x1.5xlength) in the gaps between the radiator and core support.

There's no issue with a gap between the sides of the shroud and the radiator, just the top as shown. I'll run it like this for now and see how it goes. In the previous setup with the original radiator the temps would often creep upwards of 215 degrees or more, so I'm hoping the bigger one keeps things reasonable.

Appreciate the tips and the assistance here, fellas.

 

[Ricko1966]

Now that I know your gap is 1 inch,can you just wedge a piece of black heater hose 30 inches long or so into the gap? Maybe weather strip adhesive in the front so it doesn't move it would hide the gap and unless you pointed it out most people wouldn't even notice it