hp gains in 331 and 289 motors

the biggest gains are going to be in the amount of torque produced going with the stroker motor. i would say about 30hp is the most you would gain just by changing the stroke. adding performance parts doesnt change things. in other words you get about the same hp and torque increases if you built the 289, then changed to a 331.

Well if in a moderate street perfomance build you can get 1:1 or up to 1.2:1 horsepower to cube the difference would be 331-289 = 40-50 HP gain.

The real strength of the stroker in my opinion is two fold
1. Milder idle than same HP level non stroked motor (more of a sleeper appeal)
2. stroker always seem to have a much flatter torque curve than a non-stroked motor putting out equivalent performance peak numbers

top end power won't change much, but low-end torque will climb a ton. relatively, most performance parts will net the same increases. So if you have an identically built 331 and 289 engines, the 331 might put out 350 horses and the 289 325. Adding a set of headers will have similar effects relative to the original power level... ie the 331 might gain 10 horses and the 289 8 or so.

Note these are completely random numbers only there to illustrate the general relationship.

last motor, gt40 crate motor,b-302cam, iron heads,jba headers,holley 750 dp,performer air gap 311 footpounds and 246 rwhp from 302 inchs. new motor afr 185's custom cam, same everything else- 324 footpounds and 343 rwhp from a 331 I was hoping for mor torque

check out DSSracing.com. they have the 331 setup in short or long block configurations. they may be a bit pricey, but you get what you pay for. i'm going for the 331 solid roller in my '66 fastback. the tech guys at dss said that with my combination, hp would be 475+...... something to consider.

Well the power gain depends mostly on the heads, cam, and exhaust you pick; that is where all the power lies. If you're going to spend a bunch of money on a stroker, you're probably serious about making more power, so you might as well take advantage of the extra cubes. Get your heads and intake ported, and pick a good cam, or get one made.

I built a 352 (347 kit with an 0.060 overbore which I don't reccomend...but my engine still doesn't overheat either) stroker out of my 289, got the heads and intake ported and polished, balanced the reciprocating assembly, and put in a custom roller cam with roller rockers. I made a maximum of 562 hp and 454 ft-lb of torque on the engine dyno and an average of 468.3 hp and 409.7 ft-lb above 3000 rpm--that's 1.59 hp per cube on a more thorough build up. I also picked up 60 horsepower on a jet change during the engine dyno tune...food for thought.

DJ