I have a 70 S6 and the rockers don't have lock nuts on the adjusting screws, is this normal? They back off after about 3 days and the engine starts to run like crap. I also have a 71 S6 I want to build up to replace the one in the 70 Dart. Does this have mech. cam too? Can I replace it with a hyd. cam? Who makes'em? Thanks

Yes, its normal. The rocker arms are pinched where the adjusting screws go in to make a tight fit. Sounds like they are worn out. The '71 also has a solid lifter cam, as do all slants to '80. After that they switched to hyd. cams. I believe you have a wider selection of cams for solid lifters than hyd. The '71 up cam is the better stock cam, as its the same cam used in the old Marine applications. Don't know about converting to hyd. The docter and others are way more knowledgable about that than me (and will probably reanswer my answer )

Have you tried re-pinching the rocker arms where the adjusting screws go thru? I think a judicious whack with hammer and punch, (after removing the rocker arm from the shaft) might restore the interference fit of the screw to arm.
OR, how about replacing the adjusting screw with a 273 style adjuster and use a locknut instead?

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'70 Cuda AAR
'74 Duster 360
'79 MagnumGT
'79 Chrysler 300

I have only seen this problem on a few solid-lifter rockers. I would suggest just getting another valve gear (rockers and bar) from a junker and bolting it on. I usually only adjust my valves about every 30-40k miles under normal driving, and at worst every 5-10k if I'm racing.

Lou

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Home of Slant6-powered fun machines since 1988

The 70 S6 is in the dart. After about 2 weeks it barley idles, and runs poorly. I have a 71 S6 that was in my duster. i'll try swapping the rockers. I want to run the solid cam, just hate adjusting the rockers every week. the 273, do i just need the adjusting screws and lock nuts or do i need the rockers too? thanks

I suppose it's also possible that your valves/seats are receding quickly too, but that would be awfully fast.

Lou

_________________
Home of Slant6-powered fun machines since 1988

just the adjusters, rockers won't fit. Chk to make sure that they are the same dia. first.
MP used to sell the 273/340T/A adjusters separately.

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'70 Cuda AAR
'74 Duster 360
'79 MagnumGT
'79 Chrysler 300