289 horsepower capability

It seemed to me at least three guys made it sound more common and easier than I believe it is. Read the post and it's pretty obvious who it was (wasn't you Paulie).

I brought up Alex Dennysenko because he is a well known record holding 289 racer using worked over 289 heads. The money and times he runs would be indicative of the power a max effort (class limited carb hurts a little) 289 with ported 289 heads can achieve. Just something to think about to hopefully put some perspective on the discussion.

My ported (by Valley Head Service in Northridge CA around the mid to late 90's) '66 289 heads with larger valves are not remotely close to the "ported 289 heads" the big dogs use and are getting big power out of. I got around 300 hp out of them and ran altitude corrected 12.7-12.8 ET's at 105-106 mph (13.18 ET at 103 mph uncorrected bests) on a good pass. 100+ more hp would have been really tough with that set of heads that most would consider have above average to good work done.

Mine cost around $1,600 (by memory but could dig up the receipts I guess) out the door with me providing the heads. I believe Alex is around double that in his (he posted a ball park cost a while back on his site). What seems like simple parts get way out of hand in class racing.

I'm simply saying not to look at the high end of class rules road racing and drag racing and think your ported junk is in the same league or will yield anywhere near the results. Also that just because some dyno says 400 hp on the sheet doesn't mean it's 400 hp at the track. My old carb guy who can be found on speedtalk used to speculate my old 289 could be making as much as 400 hp because of the other cars coming threw his shop that had dyno sheets and ran similar to mine at the track in very similar cars. I would be downright shocked if my old 289 could crest 310 hp on either engine dyno I was on with my new combo.

This was an interesting thread!

Surprisingly low estimates on power though, especially from Mr Joe Sherman. Guess he 289 isn't very potent...

Me and a friend of mine built a 306 for a local vintage road racer, with Brzezinski ported "cheater" heads (the local sanctioning body only allow certain aftermarket heads, so Brzezinski made a bigger, better set of Darts look like the "right" ones. With "correct" casting numbers and all...)
pretty basic Eagle bottom end (in a new era Boss 302 block) 12:1 compression, a roller cam that I won't tell you the specs on, RPM air-gap that we modified heavily we're getting about 530-540HP. Being run in the rev limiter at 8800rpm all the time too...
Three full seasons running and nothing broken yet! NOT a good street engine though...

And one of our competitors have a real boss 302 that is right over 600hp and he pulls that thing to about 10k.
Sadly non of these Fords got much to put up against a guy in a -67 Camaro though, not sure what he got (not surprisingly) cuz' he's 4-5 seconds faster per lap than anybody else..!
All cubic dollars at work.

Oh, goodie! A zombie thread! Over a decade later and now the scene has changed. Streetable 400hp 289 is a real thing now. The first stuff in the bin are factory heads — any factory heads. With relatively-recent lessons learned on cams in-combination with intakes and today's heads, they can be a very potent little package.

I will say that the next hurdle is perception, and that it is a higher-rpm engine and while still under 7k rpm, it will not drive puttering around to the grocery store. You want high-rpm power, then you get high rpm everywhere, all the time. That's the price. "But, I have overdrive!" Sorry, no, as it will drop the package out of its efficiency range, and will get better economy at higher rpm you may not want in your neighborhood or on the highway.

Without a power adder or more cubes you have to make more compromises, and one is that today you can have your cake and eat it too, but you must eat that cake all the time. "Oh, but I don't like having to shift before I'm through the intersection." Well, then you need a power adder or bigger crank, because your amazing little engine needs those gears and rpm to work right. Seriously consider the compromises before you make your choices.

Finally, I suggest you don't get hung-up on "289". A small-block looks the same from 221 to 347 or more inches. If it has 289 stickers, nobody will know differently, and I think you'd be surprised how many stock-cube engines wear badges like 331 or 347 at car shows. It's a number. Make you choices on what you need it to do, to reach your goals best, and do your thing!