1968 Chrysler Newport 383 Cam upgrade suggestions needed

Engine, Transmission & Driveline

  1. Biggredd2069

    Biggredd2069 Active Member

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    I have a 68 Chrysler Newport with a FItech fuel injected 383 engine. It's relatively stock otherwise. I'm going to upgrade the distributor soon and want to upgrade the cam at the same time. Want a little more pep. Has power brakes. Figured I'd ask for some suggestions here first.
     
  2. Lefty71

    Lefty71 Member

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    IMO, the cam with the similar specs to the Roadrunner or Magnum 440/383 cam is a very safe choice for a lot of C-bodies
     
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  3. Biggredd2069

    Biggredd2069 Active Member

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    Is that just a factory cam when I search? So search for a roadrunner 440 magnum cam? that'll make the engine a little more responsive?
     
  4. Davea Lux

    Davea Lux Senior Member FCBO Gold Member

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    As noted, the factory magnum cam is a safe choice for some added performance. How much additional power will depend on what 383 you had to start with. If it was 383 2BBL engine, that engine had a very mild cam and a low compression ratio so the horse power gain will not be that great, probably 5-10 horses. If you had a 383 4BBL engine, that will have the higher compression ratio and the horse power gain will be better, 15-20. Most of the 383 engines for that era were single exhaust with log manifolds which limit the additional horsepower because of the flow characteristics of that combination. Adding a more aggressive cam will required a reset of the fuel injection to gain more flow. It would also be a good idea to go to the stiffer High Performance valve springs as part of a cam upgrade and you can gain some additional power by going to the modern light weight push rods.

    Dave
     
  5. Biggredd2069

    Biggredd2069 Active Member

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    This was already a 4 barrel hp car and has dual exhaust. I have an edelbrock intake manifold. Luckily the computer is somewhat easily adjustable.
     
  6. Davea Lux

    Davea Lux Senior Member FCBO Gold Member

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    If it is a 4BBL HP engine it probably already has a HP style cam. The roadrunner cam would only gain a maximum of about 10hp, from 325 to 335 horse with the HP manifolds. No sure if it would be worth the time and expense.

    Dave
     
  7. Biggredd2069

    Biggredd2069 Active Member

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    My vacuum advance is messed up which is why I'm upgrading the distributor soon but I feel like the engine is lacking a little power. I don't want to get too crazy but it could use a little kick in the ass.
     
  8. Davea Lux

    Davea Lux Senior Member FCBO Gold Member

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    Rick Rehrenberg has a factory style electronic ignition conversion kit complete with the new distributor that has an adjustable vacuum advance, it's USA made and high quality. That would allow for some fine tuning of the advance to match the injection if you choose to go that route. Would need to upgrade to an electronic regulator with that system, but since you already have the fuel system upgrade, I presume that has already been done.

    Dave
     
    Last edited: Sep 17, 2019
  9. Welder guy

    Welder guy Old Man with a Hat FCBO Gold Member

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    A few things to consider- If you drop in an aggressive cam you will lose vacuum at low RPM , this in turn will directly affect your power brakes. It will be like you have manual brakes when cruising around town. You will definitely have to reprogram the EFI. Is your transmission kick down properly set up? How it shifts and when it shifts can make all the difference. What gears do you have in the back end ?
     
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  10. fury fan

    fury fan Senior Member

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    I believe no C-body got the HP Magnum cam, all had same cam as the 2-barrel engines, which means same cam as 440 350hp also.
    I have read that even some B & E musclecars got the standard cam if they had AC or maybe a Clean-Air package.

    For a 383, I would look at a Lunati 60302, or whatever the new part# is. Its advertised duration is 262/268 (don't remember the .050" duration), but the lift is higher than most aftermarket cams of that duration, because it has faster ramp rates. But the ramp rates aren't outrageous (because it's only 262/268) so it's not going to eat valvetrain parts. I would give this cam a nod over the 40-year-old factory Magnum cam.

    I actually did a bunch of 383 cam-choice reading recently, and found a lot of good forum threads, so I suggest do a lot of googling if you haven't already.
    One of the premises that a number of seemingly-sensible folks said is that it's easy to over-cam a 383, and being in a C-body makes it easier.
     
  11. fury fan

    fury fan Senior Member

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    Oh - do you have the $800 fuel-only Fitech or the $1000 one that does ign control?

    Electronic timing control is probably a big bang for throttle response after you get the mapping optimized. Can probably add 20 ft-lbs across the board (my guesstimate).
     
  12. Biggredd2069

    Biggredd2069 Active Member

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    Thanks fury fan. I'm in homework stage right now. Good advice about the lunati. I do wanna keep my brakes. It's a factory ac car but is disconnected right now. Gonna redo the cam, timing chain and distributor all at once and call it a day on the engine. Just cruise in style after that. I don't wanna over cam it or do anything outrageous with this engine. I'll be starting a next car project after this. I'll check the fi tech. Was a package deal on jegs with the fuel return system
     
  13. Davea Lux

    Davea Lux Senior Member FCBO Gold Member

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    If the engine is original to the car, you are correct 4.25/4.37 intake and exhaust lift for C-body 383 cam for both 2BBL and 4BBL engines. 440 HP engines got 4.50/4.65 which is the proposed upgrade.

    Dave
     
  14. LocuMob

    LocuMob Fluid Technician with a hat FCBO Gold Member

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    If the car is a factory 4bbl and dual exhaust, something's wrong somewhere. Fix what you have. How is the vacuum messed up? How is the distributor messed up? Advance canister working?

    I have a '68 383 4 bbl in my Monaco, and it wants to go like w raped ape, but things like a dirty carb, improper tune, and whatever else I haven't gotten to yet. The car sat for ages, and the owner before me did some things to the car, and I've gone over them again to correct/better fix them. But the car has logged 1500 miles in just over a week. The car pulls strong with the factory cam, and I have 17" vacuum. Your combo should have some pull to it.
     
  15. Biggredd2069

    Biggredd2069 Active Member

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    The distributor isn't messed up per say, just the vacuum advance portion. I just want to update the whole thing. It isn't advancing proper and is over advanced to compensate. It hesitates on first hard acceleration before kicking in. And I wonder if it also effects further into the power band. I could go basic and just fix the vacuum advance but I want it to be a good hard running engine and update the parts that wear out
     
  16. LocuMob

    LocuMob Fluid Technician with a hat FCBO Gold Member

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    That. In a nutshell. Go back to the basics. Not running right and throwing a FiTech system on it isn't going to help solve any issues, just add to them. Basic ignition system checks, fix/dial back the vacuum advance, slap the carb back on and get the basics back to square one. Then put the FiTech back on and go from there. It won't ever work right if you don't fix what's wrong, throwing money and parts at it will just make it worse, and cost you more. Factory Service Manual, multi meter, vacuum gauge, digital temp gauge, a basic set of tools, some screwdrivers, an afternoon and you should have the car running where it should be. YouTube if you're not sure, and you're done.
     
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  17. halifaxhops

    halifaxhops Well-Known Member

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    If you need a distributor I have them if needed. I would check and make sure the mechanical advance is free in the distrib also before just changing the vac advance. They are getting up there lately.
     
  18. Lefty71

    Lefty71 Member

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    @Biggredd2069 You won't go wrong there!
     
  19. Ripinator

    Ripinator Senior Member

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    Regardless of the cam you choose, make sure you buy the entire kit (cam, lifters, push rods, springs, double roller timing gear and chain, etc.) That way everything should match and work correctly.
     
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