I just bought an 84 Turbo Wagon 740 with 159k on the clock. It's in pretty good shape for a 31 year old Minnesota car. I have to do the OD bypass fix which I'm hoping should be pretty easy. I wanted however to do a quick tune up / check out of everything else.
Is there a good step by step guide or reference somewhere on what all I should do to check the engine out mechanically?
It runs good but seems to stumble a little on acceleration and at times when I give it more gas it hesitates for a bit.
Any info to point me in the right direction is appreciated!

 

extensive info here in hte 7XX FAQ.
Volvo Maintenance Hints for 700 900 S90 V90 Models

1984 is a very early 740, so probably LH II rather than the newer LH 2.2 or 2.4. some parts may be harder to get.

tuneup on these cars consists mostly of fresh oil, filter (Mann), spark plugs, wires (use Bougicord only!), cap (Bosch), rotor (Bosch), and a full inspection of hoses and stuff. coolant changes as needed, and the timing belt + tensioner every 60k miles. automatic transmission fluid every few years or 60k miles is a good idea. brake fluid every 2 years.

a compression test will tell you what sort of shape the engine innards are in.

a thorough visual inspection of the suspension components, using a prybar to wiggle the control arms looking for play in the bushings, and so forth...