The term composite is used too loosely.  A component that handles a substantial load (rods, rockers, etc) will have carbon fiber.  These are costly at the moment.    Intake manifolds, radiators, etc. will have glass or hemp fiber.  They are cheap.  The type of resin is selected based on temperature and tolerance requirements.

Looking for recommendations on a high stall convertor for the drag strip  ~4500 stall... 

Not mine

https://www.facebook.com/marketplace/item/425233492908324/

Looking back, nothing had a solid cam by 1968 - solid lifter cam was not an option on anything that model year, right?  The next solid cam engine was 69 Boss 302.  Boss 429's didn't even get solid cams at first, then magazines tested them and they added the solid design also used on 429 SCJ...so maybe Ford was hoping to get away from solids all together, but found that it wasn't going to make the grade.  Or, it was simply the individual program budgets driving each decision...Where's John Vermiersch, he'll know...

1969-71 Boss Mustangs all had solid cams too! 302, 351 and 429

Back to the original question here; why did a Drag Pak not have a solid cam when it was widely known to add performance?  The vast majority of people who wanted a Drag Pak, SCJ cared little about drive-ability, cold starts, etc.  They were tolerating ratchety deep geared locker rears, tossing smog pumps and definitely no A/C.  Ford knew the heads flowed more at higher lift than the given cam alotted, and lets add to it they had aluminum intakes available as well.  So why not?  My guess is FE tooling was at the end of life cycle and financing was all in the 429/460.  Money to apply adjustable valvetrain and aluminum pieces just wasn't there for our beloved 428.   Ford essentially admitted the solid cam would have been better, having applied it on next generation 429 SCJ Drag Pak.

Very nice engine.  Could you give more info on the heads (as-cast(?) port volume, cfm, valve sizes).  Thank you.

Yep that was us.  Your wagon launches beautifully.  I forget, was yours a marine-side oiler? And which heads and cam are you are using?