Thanks for the great tip on easily identifying an already installed solid or hydraulic cam.
I asked this question many times over the years, and you are right - very few are aware of this apparently.
Just checked my mechanical 261 cam and indeed it has one casting lump.
Just from reading on this board for many years, it appears there are many Frankenstein 235s on the road running pieced together with mismatched parts.
Amazing what these engines can take and still keep running for years.
I replaced all hydraulic lifters with new ones on my late 235 daily driver last winter.
- The engine never ran better in the previous 11 years.
I believe the later 235 cams are harder. Both solid and hydraulic lifters are also different from the earlier years and look almost identical.
I think the trick with hydraulics is to not overtighten the rocker arms.
I only tighten the rockers 1/8 turn after clicking stops with the lifters and pushrods spinning freely.
The manual suggests turning 1-1/2 turns after clicking stops.
But I drive often on freeways for hours and prefer
this method .
I can only speak from personal experience and observations.
It seems save to suggest, if you got collapsed hydraulics on a late 235 and always stay under 3000rpm - get a new set of OEM hydraulic lifters and enjoy a quieter ride.
