454 Swap

[Maintenanceman]

I searched but still have a few questions. Im POSSIBLY looking at swapping a 454 in for my 350. Ive got a '85 Silverado K20 with a granny 4 speed. Looks like the bell housing and input shaft will all be usable when doing the swap? What about motor mounts? any difference? As far as keeping cool, will I need a different radiator? Is there anything off of the 350 that I will still be able to use after the swap? Such as accessories? What about the rear end? Any modifications to that? Looking for any and all suggestions available. Is there any type of 'guide' or 'how-to' when doing this swap?

Thanks,
Ben

[Captkaos]

The actuall accessories will work, but you will need an alternator bracket and A/C bracket .  I used my SBC power steering brackets.
The 454 uses the same mounts as a SBC, so just yank it and put the mounts from the 350 on the 454 and drop it in.
I had a 3 row in my truck when I switched and never had an issue with overheating.
You exhaust won't align, so you will need to fab downtubes to work.
If you are only changing the engine it won't effect your drivetrain, so the trans/driveshaft/reared can stay the same.
You will need a new flywheel and clutch assembly as the SBC stuff won't work.

[hilton850]

Captkaos, could you explain the differences in the clutch assemblies?  I always thought you could reuse the clutch assembly.  I've never personally done this swap but I do know that my particular truck has a 12" clutch and it would bolt on to the old dump truck we have on the farm that has a 427 big block in it, but this may be an exception to the rule.  I am also pretty sure the flywheels are in fact different, someone can correct me if I'm wrong but I believe the 454 is an external balance engine and the 350's of this era are internal balance, so the 454 flywheel will have a weight on one side while the 350 flywheel will not. 

[Maintenanceman]

So I wont need to beef up the transfer case or rear end? and Im curious about the clutch assemblies as well.

And another thing, Ive found a 454 for pretty cheap but it say it only works with 1973-1974, 1976-1978, 1980 Chevy K20 Pickup year models? whats the difference in mine vs. these years?

[Captkaos]

A) The 350 and 454 flywheel are not the same, so you will have to get one for the 454.
b)  You don't want to use a used clutch disc on a new flywheel.  You "can" but it wears quicker and I would prefer to replace it and have it last a while.

No you don't need to beef them up.   They can handle a fairly build 454.

[Maintenanceman]

Ok so its a pretty straight forward swap but what about the year model differences?

[hilton850]

10-4 capt. 

I agree with you 100% about faster wear and tear putting the used clutch on a new flywheel.  I was under the impression that you were saying it wouldn't fit for some reason....in reality you were just saying how to do it "the right way" so to speak.  Thanks for the clarification.

I have no idea about the year model differences....sorry

[Captkaos]

A SBC is a SBC regardless of size, same goes with a BBC.  (this is talking up to 1991)
As for trucks, the same applies.  Motor swaps are simple on these trucks.  Everything will fit.

[Maintenanceman]

Awesome. Thank you sir. So let me get this straight, All I will need to do the swap is New AC and alternator bracket, then engine, and a new clutch assembly and fly wheel. correct?

[Captkaos]

you missed Exhaust...

[Maintenanceman]

Right. Ill just put LT's on and then drive it to the exhaust shop and let them button it all up for me.