Yes, it is possible to mount the rotor 180 off, and not all that uncommon of an error.

 

How about leaving the dist where it is at for now, and finding a smaller diaphram? It sounds like you are close to having the right timing if you could just turn it a little more. Good luck, Jag

 

I might guess if the vacume advanced hits the manifold you are one tooth off on the dist install. Remove the dist and move one tooth only, should give more adjustability..
Gerry

 

Another possible cause is the timing belt has jumped because it is worn. It is a common problem on the Y-block with lots of miles. You can check it by turning the engine by hand to bring the #1 piston at top dead center and looking at the timing pointer on the crankshaft to see where your initial timing is at. The manual says it should be 3 to 6 degrees BTDC.

 

Gerry and Roger,

Thanks for the suggestions. I'll check them today.

I put new spark plug wires and fresh plugs in. I am using the Autolite 46 recommended by the auto parts store. Set the gap to .035". The old plugs were a mix of brands and tip sizes. I put a timing light on it and got it to 4 degrees TDC. It continues to run strong under load up to the mid-RPMs where the popping starts. At highway speed, maybe 60 MPH in 3rd gear on the manual three speed, the popping continues. But it sounds like it is just one or two cylinders.

I just received my 1958 F-100 shop manual. I was planning on checking the distributor system against the manual today. I have also downloaded a manual for my Edelbrock card and will be fine tuning it today.

I had a shop adjust the vales and replace bent push rods during a major tune-up. Could my problem be something in the valve train?

Thanks,
Dave

 

I resisted telling this possibility as long as I could, to not get your hopes down, but now that you seem to think it's only from two cylinders, it is more apparent. If the popping sounds like popcorn, it may be a blown head gasket. pull the plugs and do a compression test.

 

If the dizzy is 1957 or later it uses a combination of vacuum and centrifigal advance. You may have a weak/broken spring in the dizzy for the centrifigal advance. This would mess up the timing at speed. Another thing to check.

 

Thanks all for your help. My '58 F-100 shop manual arrived from the good folks at NPD and what a wonderful read. Furball69, thanks for trying to be gentle with me about the possible blown head gasket. The manual is very specific about how to use compression tests to differentiate valve from ring from gasket problems. I do want to keep my Y-block, although a donor 302/AOD has a certain appeal, so I'll use the manual to troubleshoot and repair my loadmatic distributor and check the compression.

Thanks again to all of you for your advice and help. I'll let you know how this turns out in a future new thread.
Dave

 

Awesome. It's always a good idea to throw a trickle charger on your battery overnight before doing the comp test, just to make sure she's good to go with all that cranking.