For the past two weeks or so my engine has been clanking under acceleration and a tad during cruising. My radiator was busted for a couple months, so I had to fill it before I went anywhere. I just put in a new one, but I think the damage has already been done. it definitely sounds like valvetap... i checked the oil and it was fine, and i thought maybe i just got a cruddy tank of gas, but i've filled it up a few times since and it's still doing it. I use the regular unleaded, just like I always have so it's not because of gas or low on oil... Anyone have a suggesstion, I'd rather fix it now then have to spend $500 on heads later. Thanks, Steve. (oh yeah, the engine is a 305 carbed with auto trans, just in case that makes a difference)

 

It's not a valve, or anything to do with valves. Sounds to me like you might have spark knock. Just for the fun of it, try a little higher-octane gas, and see if it clears up (or at least if it helps).

It also might just be an exhaust leak, under the hood, very close to the engine; like where the manifolds bolt to the heads. You might want to just tighten all those bolts.

 

I'll try some higher octane gas, and this Sat. I'll play around with the manifolds a bit and see what's up. Thanks.