I’ve been getting my 67 running with my son, it’s been a great father son project. For the last year I’ve tried to just get it operational after sitting along time. It has a numbers matching 340 with st300 with 98k miles on them. I basically got it running and driving to find out I have a blown head gasket on passenger side. I haven’t done a head gasket before, looking for advice. Thinking about doing my self? I’ve also thought about getting a rebuilt 350? Thanks
What do plugs look like and do leakdown test very easy to do with air compressor. That will confirm head gasket leak
Continuous white smoke/ steam/water from that side rail pipe Continuous black water from that side exhaust manifold ( found a leak there, as runs water comes from head) White steam/ smoke filled that side valve cover Rock hard radiator hose Low coolant I wasn’t 100% sure yet and I was going to try a compression test? To confirm Thanks
I will do further investigation for sure, and update when I have time to do that, I guess I was just thinking a couple steps ahead as usual and going man should I even attempt that myself if that’s the problem thanks Joe
Ok so I did the exhaust gasses test in the coolant and it tested positive, so I do have head gasket leak. As of now I’m thinking about three options 1. Pull the marching numbers motor and get it rebuilt (2800$) 2. Pull heads and do it myself (cheapest) 3. There is a guy selling a 340 rebuilt he had as spare motor (1500$) All advice welcome
Head gaskets on an old buick engine are just about as easy as they get. No need to fuss with the distributor, the non-adjustable valve train- its a very simple job. Get after it!
Head gaskets are pretty easy with the exception of intake and head weight. They aren't light but it's otherwise not a bad job. I'd rather pull heads than timing covers but that's just me. In any event, if it needs rebuilding once you get the heads off, you'll have the option to rebuild it. I just rebuilt my 71 350 and it took a while because machine shops were COVID-backed up. You might call a few local machine shops to see how they are for timelines. Whatever they say, minimum is to double it. Machine shops are some of the worst for time estimates. I wouldn't buy an engine that was "rebuilt" without pulling the heads and pan to check things out. $100 in gaskets will tell the tale. Too many wankers out there trying to pull a fast one on folks. A 350 is also a good choice. It will drop right in and parts availability is slightly better but not enough to abandon the 340 if it is easily returned to service with a head check and new gaskets. However, if you go with a 350, see if you can score a 350 turbo trans. It will wake up that little car.
