8.1 vortec into 1979 k30

[Lu Blunt]

Recently found an 8.1 vortec for a good price. Wanting to swap it into my 1979 k30 with 350/sm465/np205. I’m still doing research and collecting parts. Id appreciate any recommendations for a shop in Colorado to help with the swap.

 

[Vbb199]

You may need an adapter to mate the motor to the sm465. That right off comes to mind

 

[Rickf]

Might not be able to use the a/c compressor (if needed) in that location.

 

[Hunter79764]

From memory, I think I've heard that the Medium Duty truck accessories are the best fitting in a swap application, but I'm no expert. I've got one in my Kodiak based motorhome if you have specific questions.

 

[hoagster]

You may need an adapter to mate the motor to the sm465. That right off comes to mind

You are correct and Advanced Adapters has what he needs. I have a 5.3 LM7 connected to s SM465/205 combo. And The A/C location will not work. Easy fix with a upper adapter and a different belt. The A/C wiring will reach to the upper location without changing it.

 

[Vbb199]

Unless you notch the frame ^

My buddy did a 5.3 swap with a 200r4 in his 85 c10.

He needed an adapter from advance adapters, and he notched his frame to clear the compressor

Personally I think that's very poor workmanship, but to each his own.

 

[yevgenievich]

Van accessories fit without notching

 

[Lu Blunt]

As far as I know the 8.1 vortec uses the 502bbc block which is based on the 454 big block, not LS* based. 8.1L is 496ci and no LS based block can be bored and stroked to that large of a displacement. 8.1L uses normal sbc/bbc engine mounts and bellhousing bolt pattern

The 8.1L should mate to the SM465 no problem. Use an 8.1L manual flywheel and pilot bearing with my current clutch setup. Ive read you have to open the pressure plate mounting holes just a tad to allow for the larger metric pressure plate to flywheel bolts to pass through as well as remove the two dowel pins from the flywheel. The 8.1L also clears the ORD HD engine crossmember so that’s what I’ll be using.

My 79’ k30 is non-ac so no need to keep the ac compressor. Also read the stock 8.1L exhaust manifolds wont clear the frame but you can use any 454 manifold/headers

I’m still doing research and collecting parts

 

[Shorty81]

I have the old school 496 mated to sm465. Torque monster!

 

[Dooley]

You will need the big block bottom power steering pump bracket for the hydra boost pump also.

 

[BearKing]

As far as I know the 8.1 vortec uses the 502bbc block which is based on the 454 big block, not LS* based. 8.1L is 496ci and no LS based block can be bored and stroked to that large of a displacement. 8.1L uses normal sbc/bbc engine mounts and bellhousing bolt pattern

The 8.1L should mate to the SM465 no problem. Use an 8.1L manual flywheel and pilot bearing with my current clutch setup. Ive read you have to open the pressure plate mounting holes just a tad to allow for the larger metric pressure plate to flywheel bolts to pass through as well as remove the two dowel pins from the flywheel. The 8.1L also clears the ORD HD engine crossmember so that’s what I’ll be using.

My 79’ k30 is non-ac so no need to keep the ac compressor. Also read the stock 8.1L exhaust manifolds wont clear the frame but you can use any 454 manifold/headers

I’m still doing research and collecting parts

You have my attention. I so want to put one in my 1981 GMC K2500 HD.

 

[BearKing]

I have the old school 496 mated to sm465. Torque monster!

That thing is BEAUTIFUL. I love RED.

 

[fast 99]

Kind of wondered about this conversion. I am from the old school more cubes the better era. Noticed at the local pick and pull no one was buying the 8.1L motors. Have seen 3 or 4 in the last year that got crushed. If I had the storage space would have bought them. Know there is a lot of interest in LS based engines, many of those are sold within a week.

Seems from the above comments using those motors isn't that difficult.

 

[Bextreme04]

The 8.1L is totally different than the Gen VI and older BBC engines. It shares almost nothing and you can't use standard BBC parts on it. Head bolt pattern is different, intake bolt patterns are different, crank is different. It IS NOT based on the Gen VI 502 block. It is a Gen VII BBC and you can basically only get performance parts from one or two different manufacturers, and they are VERY expensive. About the only things that will bolt directly on from old BBC engines are the exhaust and starter. It DOES have the standard chevy bellhousing pattern as well. If you are leaving it stock, that's not really a problem. But if you want to do any modifications you are basically stuck with Raylar engineering https://www.raylarengineering.com/. They have an entire section on engine swaps of the 8.1L into older cars. https://www.raylarengineering.com/vortec-8100-engine-swaps.html

It DOES NOT use the standard SBC/BBC engine mounts. They are basically LS style motor mounts and you will need an adapter to fit to older clamshell mounts. https://www.skspeed.com/dirty-dingo...otor-mounts-gm-8-1l-496-bbc-to-3-bolt-mounts/

 

[yevgenievich]

Interested notes on parts compatibility. With a specific gm crank, rods and pistons swap between gen 6 and 8.1l. Cams are also direct swap but different firing order