Should I spend any money on a stock engine 305 with 89K miles, to get the HP up. Or should I save up for a new crate engine.

 

You can get some speed parts, but just don't get anything 305 specific (heads, cam). If your 305 needs machine work definitely don't have that done, get a 350.

 

The '84 LG4 was low compression. Anything you do to it will have a reduced effect vs. a higher compression 305.

Some things that make sense are exhaust and air cleaner. Fixing those will transfer over to most any SBC option.

The cam isn't 305 specific, but it will be flat tappet. You could transfer it over to a roller block if that's what you happened to get later, but that would be a downgrade to a roller block.

Of course, you could do the HP things on your current 305, including heads, if you'd be satisified with the results and not "need" to go with a bigger engine.

 

What i ment was a cam sized for that low compression 305. A bigger cam would hurt power because of the low compression.