Engine swap question, 350 -> 454

[willem445]

Hi guys,

I've got a 1980 Chevy K20 with a 350 in it. The 350 runs fine but leaks everywhere and is needing a refresh. I've got a 454 in really nice condition from a '78 C20. My K20 has manual SM465/NP205. The '78 C20 is a 454/TH(350 or 400, not sure). Transmission is bad in the '78 so I will not be using it.

Is there anything special I will need to swap in the 454 from an auto tranny and mate it up to a manual? Bell housing? Clutch? Flywheel?

I've never done a swap before so this will be new to me.

[kwmech]

All you need is a 454 flywheel, everything else should bolt up. You can use the same clutch over as long as it is in good shape.

[willem445]

Perfect, thanks!

[bigdaddy4x4]

you may need to change the fuel pump the 454 fuel pump on some of the big blocks they are longer than ones for a small block and will hit the cross member

[geezer#99]

Don’t forget the pilot bearing!

[Dead Parrot]

Check the exhaust for fitment.
Is the radiator in the K20 a heavy duty version?
During the swap, might add new heavy duty battery cables.
While the engine compartment is empty, good time to check/repair/replace those wires that sit behind the motor and are normally a PITA to get at.

[willem445]

Thanks all for the suggestions thus far!

Just to summarize so far:

- 454 Flywheel [https://www.summitracing.com/parts/r...ake/chevrolet]
- Clutch (maybe, not sure on condition of existing clutch, might replace while it's separated)
- Fuel pump
- Pilot bearing [https://www.summitracing.com/parts/ram-bu656#overview] (not entirely sure this is correct)
- Big block headers
- Radiator (maybe)
- Heavy duty battery cables (optional)

@Dead Parrot My existing 350 has headers and bolt on glass packs. I'll either bolt the glass packs onto big block headers or actually do normal pipes and muffler.

As for radiator, I actually just swapped in a new radiator due to a leak on the OEM. It's a champion CC161 3 row radiator. Will this work or do I need something bigger?

Good suggestion on battery cables and engine bay wiring. I've actually been considering completely rebuilding the engine harnesses. I did redo/patch them a few years ago so it's not too bad currently.

[willem445]

If I would replace the clutch while things are torn apart, what would be a good option? Would be 454 mated to SM465 3 speed.

This looks like a decent budget minded option for stock engines. I don't currently have any plans for building a high HP/torque 454. Might eventually replace intake/carb, maybe cam.

https://www.summitracing.com/parts/sum-700810