Looking for what I should add to the truck currently have a lly with marks 65mm drop in 100 overs built trans minus billet shafts studs ect but stock lower end at the moment will marks 68mm be a marginal upgrade for power? Is it worth it also lower end just stud the mains new rods delip pistons new valve springs ? Should be enough for a while right ? Intrested in all opinions .
Lets start with the questions below. You're asking questions that can get quite blurry on where the line is.
1) What CP3 is in the truck currently?
2) How do you use the truck? IE do you tow, is it a toy, is it a work truck etc.
Personally I would think if you have 100% inj, 65mm, and the OEM CP3 still keeps up you're maybe low 600s which is less than that 65mm turbo is capable of. If you upgraded to a 72mm you will be quite under fueled for what that turbo can support at that point. If it were my truck with the mods you have and an OEM CP3 the first thing I would do is upgrade to a 10mm or 12mm to help support what the rest of the system can do with a 72mm/100% inj.
As for the engine build there are
MANY ways to skin that cat like overall HP goal etc. For a budget/1k "safe" build using something like a Callies Durastar, SoCal/DHD/Wagler budget rods, Mahle motorsport or Fingers cast piston, ARP hardware throughout etc is a solid choice.