I just got done bolting a rebuilt head onto the engine of my '81 f100 with a 300 (fixing blown head gasket). The head I swapped out was a replacement put in by my uncle (a skilled old-school mechanic) about 20 years ago when my grandmother owned the truck. It only has 70k original miles on it.

I thought it was strange that there was only one alignment dowel, which permitted the gasket and head to pivot during installation, but I figured that the bolts would draw the head into proper alignment during tightening. I made sure that the gasket was aligned as well as I could by looking down into the bolt holes, and I went ahead and torqued the bolts down. Shortly afterward, I happened to be inspecting the original head that was swapped out by my uncle, and noticed that there is an alignment dowel stuck flush in the rearmost right side bolt hole. I found this somewhat disturbing, but not surprising because I've never changed a head gasket where there weren't two alignment dowels to ensure positive alignment.

My questions are these: If the head/gasket were slightly crooked on the block due to the missing dowel, could that have caused the head gasket to fail? If so, it follows that the same problem could recur, and I should get a replacement dowel. Second, if I unbolt the head to replace the dowel, can I reuse the head gasket? I wasn't sure if the gasket crushed under torquing in such a way that it wouldn't hold up under retorquing.

Thanks in advance for any help!

Bill

 

In the absence of any replies, I unbolted the head and replaced the missing dowel pin just to be safe. I reused the gasket too. I guess I'll find out in time if I made the right decision.

 

The more urgent the question, the longer the response time. Here and everywhere. You did the right thing to take it apart and put that dowel in there. I pulled a 289 apart that was put together w/o the dowels. Had to hammer the pistons out.

As for the gasket, I trust you didn't glue a torn one back together or reshape a distorted one, in which case you are probably OK.

 

Well, I just thought maybe the question about the head gasket failing because of missing dowels was a bit too esoteric to get a lot of immediate responses, so I did what seemed most prudent. Fortunately replacement dowels (made by Fel-Pro) were available at my local Napa. It would've been a bigger issue if I had to get them from a dealer or specialty shop. (I wasn't so lucky with the rocker arm nut that mysteriously split upon tightening!) Thanks for the input. And yes, the gasket was "almost new" -- new as of the first time I bolted the head on.