1948 Buick - Do I Have Hydraulic Lifters?

[Sir Gonzo]

I have a 1948 Buick Roadmaster Series 71 with the 320 engine. According to the shop manual:

 

Adjustable lash valve mechanism is used in all 1948 Series 40-50 engines and in 1948 Series 70 engines up to No. 5192693.

 

Hydraulic self-adjusting valve mechanism is used in 1948 Series 70 Dynaflow Drive engines, starting with No. 5192694.

 

My engine number is 51939427. Maybe I'm overthinking this, but it seems unlikely to me that the shop manual references engine numbers in the 5 million range while my engine number is in the 51 million range (7 digits vs. 8 but both starting with 519, curious), so I'm not sure I can trust what the shop manual is saying. Feel free to tell me that those numbers are totally reasonable and just go with what the manual is saying. The manual also says to look at the labels on the rocker arm cover, but anyone could have put any label on the cover in the past 70+ years so I can't go by that.

 

How can I tell if I have hydraulic lifters or not?

[Ben Bruce aka First Born]

Sir Gonzo,  trust the manual.  The last digit on your engine, the 7, indicates the engine was installed in a series 70 , Roadmaster.  As were all 320 engines by this time.    The 248 engine will have a 4 or 5 there indicating Special or Super.

 

  One  way to determine lifter status  is to remove the push rod cover and inspect.  Push rod will be down inside a manual lifter.   On a hydraulic , the pushrod will be sitting in a shallow "cup" at the top of the lifter.

 

 

  Ben

[Sir Gonzo]

Thanks, @Ben Bruce aka First Born!