I took the 86 460 to the rebuilder today and they will be putting a new timing chain and gears in the long block. Members here recommended that I get a "straight up timing gear". When I mentioned that to the shop they did not really know what I was talking about.

I am not going to smog this engine which is why they said to get the straight up timing. But I am not sure why or what difference it makes whether I just stay with the set that came in the engine.

And the last question if I go for the straight up set do I just order that part or do I order it for an older 460 engine and put it on the 86 engine.

I am confused

 

One early trick to reduce emissions was to retard cam timing. This reduced emissions but it also reduced engine power. They could do this by using the same cam, just rotating it slightly relative to the crankshaft. As such a 100% true OEM replacement timing set might include the offset, whereas a performance replacement will have the cam oriented "straight up" for pre-emissions era performance. I'm not surprised that a shop wouldn't know anything about this. I know I didn't until I was told about it here.

Many high performance aftermarket chains have different markings so you can install them "straight up" or x degrees advanced or x degrees retarded to modify the characteristics of how the cam behaves in the engine.

Trouble is I have no idea if your 86 has a factory retarded camshaft or if they had figured out how to beat emissions using other means by then. It may be that the ONLY chains you can get for your vehicles are straight up. Perhaps somebody with more knowledge will chime in soon.

FWIW, when I say timing chain I am referring to the chain and sprockets, the chain has little to no impact, it is the orientation of the sprockets.

 

To get a stock replacement that is "straight up", get one for the 1968-1971 429 & 460.
And yes it would be worth doing.