AFR 185s too big for my 289?

Discussion in 'Classic Mustang Specific Tech' started by Cobain03, Dec 1, 2009.

  1. well i was going to do a 347 build, but decided to just build my 289 cause of money issues. head cam intake swap and be little more fun and a LOT cheaper. i already have the heads, was going to use them on the 347.

    will they work on my 289? or should i switch to the 165? havent decided cam yet, intake will probably be the stealth.
  2. 185 sounds a little heady for a 289...good if it's a big revver but probably not a great combo for the street.
  3. They will run great with a nice tight lash solid roller. The 289 is supposed to spin anyways. If you don't want them I'll take them.
  4. Probly wont hurt anything, but a bit overkill for a small engine. You could run a high lift cam to take advantage of the big heads, but keep duration short to keep it streetable. May even look into a custom grind roller cam. Seems like a lot of people are doing it, so I dont think its much more than any off the shelf cam.
  5. it will be a non roller hydro cam. may go custom route like you mentioned. how much lift/duration would be best for a good street car?
  6. I'd stay less than [email protected] around 550 lift but really depends on CR as well as the rest of the combo/usage, with those heads you probably want a smaller cam to keep low end.
  7. afr 185's will work just fine with a mildly modded 289. thats what those heads were designed for. the 185's will wake up the 289 in fact, as they are worth about 40hp just bolting them on.
  8. All good advice, but you first need to address the compression ratio loss you're going to see. Are the heads you have now, 58 or 64 cc chambers ? You will want the 58's and preferably milled an extra .030 to ge the chambers even smaller. Any cc change in the swept volume increases exponentially the comp ratio the smaller the engine is.
  9. my friends dad has them on his 289 with a .560 230* cam, 10.7:1,650 carb and made 444 hp on a engine dyno.Runs very good and streetable with a 5 speed and 4.11's
  10. AFR185 heads, 670cfm Holley SA, THUMPR cam, forged internals... broke the 8" rear.
    Now have 9" TrueTrac 3.50 gears.
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  11. these heads are 58cc. i believe me engine is around 8.5ish compression now. i have someone lined up to trade to 165's if i should but seems like you all are telllin me to stay with the 185s.
  12. If you've got someone to trade for 165's I'd jump on em. They'll be a better match for a 289.
  13. I wouldn't trade. Worked great on my 9.0-1 308. Even IF you lost a little bit, you'll want them later when you build a better engine, or that stroker.
  14. Use them and avoid the word "hydraulic" in your cam choice. It would really be a shame to not build that engine to produce usable power up to 7000 rpm. Don't fear the solid and don't fear rpm with a short stroke 289! A 289s piston speed at 7000 is less than many big blocks at 6000 it, you'll be glad you did. Put ARP bolts in your rods and use ARP main bolts and your good to go. Oh yea, run 10:1 compression and a good tight quench of .040 or so too.

    You may be so happy with your 400+ HP 289 you'll forget all about strokers.
  15. well if im going to take it apart, then i might as well do the stroker.
  16. I remember reading an article that compared AFR 165s to 185s on a 302. The 185s made more power across the entire rpm band, even at the bottom end. I don't remember what site it was on but google "Afr 165 vs 185" and you should find it.

    As an aside: I'm planning to run the 185 competition heads with a 2.1L Kenne Bell blower when I rebuild my 289 :D
  17. Interesting...that sounds counterintuitive...the lower air velocities in the larger ports should make things a little more dog-ish down low. Based on the 351C-4v I drove, I'd imagine a similar effect with the 185's on a 289...that motor was a real dog under 3500.

    EDIT: Just looked up the articles. It's true on both a 302 and a 347 the 185's seem to outperform the 165's even down low. Still, given that the 45ci spread between those two motors didn't seem to affect that part of the outcome, I doubt the 289's 13 cube deficit vs. the 302 will change the story. I've changed my mind now - go for the 185's!

    Enjoy the blown 289. That sounds like a blast!
  18. One more thing to ponder is clearance with the stock pistons and 2.02 vs 1.94 valves.