I am planning to replace my 305 TPI with a used 350 TPI from a GTA that is supposed to have around 100k on it. Must I have any machine work done in order to rebuild and drop it in?

I also don't know much about compression. How do I handle this?

 

It depends on what it needs. Chances are you can just drop it in and run it.

A minimal rebuild is replacing gaskets, rings, timing chain set and bearings with no machine work. Still going to cost at least $500 for just parts.

A good rebuild without boring the block for new pistons is honing the cylinders for new rings, decking the block to make sure it's square and milling the heads to make sure they're square.

Heads should be rebuilt or replaced since the valves and guides will probably be worn.

Many times if all you need is a stock type engine, it's going to be cheaper to just buy a stock replacement engine already rebuilt.

 

Is there a way I can tell if the engine needs machine work? Also, does rebuilding the heads require any machine work?

 

If there's terrible noises when it runs or it's blowing oil out the exhaust, it will probably need to be rebuilt. A cylinder compression and leakdown test will tell you a lot about the engine.

To rebuild heads, they need to go to a machine shop.

 

With the way machine shop prices are going up, it's cheaper to get a rebuilt engine unless you can get a good deal on machining. After the engine is out and cleaned, check all the clearances. That will let you know where to start with machining. Honing the cylinders is a good idea.... it gives more room for rebuilds. Only 5 cubes doesn't make a big enough power difference to justify the cost unless it's needed for cleaning the cylinders.