1974 454 into 1986 k10

[SsgtCrawford]

Hello all,
This is my first everything when it comes to rebuilding and restoring a truck I have a 1986 k10 that I recently purchased and the guy gave me a 1974 454 bare block along with the truck I'd like to build the 454 and put it in the truck, my question is will it fit perfectly do I need to change motor mounts etc? Right now it has a 305 in it what will I need to make the swap. Thanks

[Engineer]

It will not fit "perfectly" but it will be pretty darn close.

Did you get motor mounts with the 454? If so use them. Small block motor mounts will work but you may have to use a spacer between the engine and engine mounts to get the fan to properly center in the fan shroud. And the fan shroud will be different for a big block.

You will need new brackets for your alternator, power steering pump, and A/C compressor.

454 uses a specific flywheel so make sure the one you use is weighted specifically for the 454.

Bell housing should be the same so no worries there.

Ignition distributor should be the same.

Your small block's carb ought to be calibrated pretty close as well. You may want to swap it out because those things could be pretty complicated with all of the emissions add ons.



What transmission do you have? Unless it has been swapped out the OE 700R4 auto trans for the 305 can be predicted to live in minutes behind the 454.

[SsgtCrawford]

What kind of spacers? And I believe it is the 700r4 what transmission should be used?

[Engineer]

Maybe nothing more than a 1/4" spacer like the bracket for the transmission strut bars. You would just have to drop it in and see if your fan rubs the bottom of the fan shroud. That of course, is assuming you can find a 7 blade clutch fan and an original 454 fan shroud.

The 700R4 can and should be beefed up to handle the torque of the 454.

[zieg85]

Probably not an issue but if you're required an emission test you will fail miserably.

[SsgtCrawford]

If I did need it to, why would it not, and what would make it so it would?

[zieg85]

If I did need it to, why would it not, and what would make it so it would?

First of all a half ton never got any larger engine than a 5.0L which was choked down with emission stuff.  86 was the last year for carbs and had the most stuff on it.  A 454 was available in a 20 series but the higher GVW has higher numbers to meet meaning less emission stuff was on the engine.  In 74 nothing was on it besides a PCV and a charcoal canister to vent the tank.