well, my 305 spun bearings, so I put a used 350 in there.

In the mean time I had to do several intake swaps before I got it right...

Then just the other day I finally got the timing set close enough, and coolant all filled n all that good stuff.. So I decided to give it a couple revs and find out what that hooker sounded like...


Well, I'm pretty sure that the straight plug boots on my headers were starting to melt or something, causing a misfire.... but basically... i revved it up to about 3500 in park (I know, shouldnt rev it in neutral...) and all the way up to 3500 sounded good. So I let it off, and on the decelleration it made an audible knocking sound twice... at first I thought that it sounded sort of like how a flowmaster would, or something with hollowed out cats on decel.

But then I kept thinking about that noise and couldnt help but think perhaps it was knock... but i didnt think that would make any sense... since there would be more oil pressure on the bearings on decel, than on accel... right?


Could this sound just be from a loose exhaust bolt? Or do I need to do another tune-up? Or did I keep the timing advanced too far ( i couldnt read what each tab was, but I put it to the closest to 6* advanced I could imagine it would be on my tab)?


What I'm THINKING is that a couple spark plug wires got burnt out, and my platinum +4s are probably junked by now (no I didnt expect them to last, I just wanted them in there so I wouldnt have to worry about my gapping abilities when I started the car for the first time), which causes a pretty bad rich condition, which when it gets to the cat, it actually pops/explodes slightly.

There is also a lot of smoke coming from my driver side header, but I want to let it go for another couple hours to make sure it's not just grease and stuff burning off from the prior owner and my handling them.


Anyone got a take on my rambling?

 

I'd check the torque on the header bolts and probably replace the platinum plugs with regular ones. I've noticed a lot of people complaining about the platinum plugs giving them grief. I'm assuming that the 350 you dropped in was either rebuilt by you or given a cursory glance before you put it in. I had a problem like that a couple of times. Only once was it because the header flange was warped pretty badly. Mostly it's been loose bolts that let an exhaust leak make quite a knocking racket. Change the plug wires too if they look kinda bad. Let me know if that solves the problem. If it doesn't, we'll explore a couple other avenues.