With a set of AFR 165 heads, a ported PerformerRPM intake, a 650cfm carb, headers, 10.5:1 compression, and a custom cam, IMO there's no reason you couldn't make about 415hp. I'd put in a windage tray and 5.0L low-tension metric moly rings to free up some HP too.
If budget isn't an issue, add a T&D rocker shaft setup and some nice comp beehive valvesprings.
Either way, it ought to be a 7000rpm pump gas monster with good tractability.
The squirrels in my head have spoken.
Cobra 5.0L & AOD swap, here we come.
IMO there's no reason you couldn't make about 415hp
uhhh....just don't let it near a dyno or I think you'll be disappointed. To make 415 (either gross or net) out of a streetable car you'll need more cubes or a power adder. On a chassis dyno, I bet my 289 wouldn't make over 300 HP, and it has all the goodies including the afore mentioned AFR heads.
But I seriously doubt it will be easy to drive on the street. A friend of mine has a 377 hp 302 in his GT-350. It is a complete doge on the bottom end and makes that 377 at 7200 RPM. If you rev an engine high enough it will make the HP (assuming it's designed to do so), but it's far from a good street engine. IMHO, 300-350hp is pretty much the upper limit for a streetable 289.
With my 302 I have a cam, AFR heads, and a supercharger (will be on in the next week) putting out 8-10 psi as well as numberous other mods I would be happy with 400 hp. My tuner seems to think 450 rwhp is more likely. We'll see in a few weeks, I am not holding my breath. To get 400 on a 289 without a power adder is not realistic if you want to drive it on the street. I agree with dodgestang 330 would give you one heck of a ride in these old cars. I'm just a little greedy I guess.
402 hp at 5700 rpm
373 lbs ft at 5000 rpm
300+ lbs ft from 2000-6000 rpm
Assuming that AFR is not exaggerating too much, I guess that would qualify as a 400 hp engine with at least decent street manners. Of course, it's a 302 rather than a 289, but an equaly equiped 289 would not be far behind (5% if it makes the same amount of hp/CID)
So, make that 302 a 289 (-5%), put it on a chassis dyno (-15%) and you end up with 324 hp. Considering the test is an advertisement and that the engine lacks some accessories and a full exhaust as well, the output once in a car may be around 300 hp at the wheels. I can assure you it will be a blast to drive.
How much horsepower can I coax out of a 289 without stroking it and still make it comfortable to drive?
What are the components needed to do this?
I don't know what is comfortable. Current 289 has stock heads except smog bumps were ground down and upper ceiling sort of D-ported. 600 Vac Holley on Weiand 8006, stock cam and Tri-Ys. It is about 220-230hp gross based on chassis dyno and 1/4 mile trap speed. As we know that the horsepower is all around ie that is the air I may try just adding AFR185s I have on my hood now. They are intended to 342 but since that have been coming on last three years it may not be ready next spring anyway. So why not on 289, it's only a head swap.
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Hot Rod December 2005 did a 5.0 EFI build. They tried to build a typical steet motor (starting with a junkyard 91 Mustang GT 5.0). They used Edelbrock Performer RPM heads, RPM II EFI intake, Comp Cams X#270HR cam (218/224 .544 lift), stock shortblock with 9.2:1 compression. They tested with no accessories and their best pull was 388 HP @ 6000 RPM. I would guess that the EFI motor would make a few more ponies than a carbed motor (but don't want to start that discussion!), and the 388 would probably be about 315 RWHP in a stick car. The motor had a pretty flat torque curve from 3000-6000 RPM (thank you fuel injection!) and hit 315 HP at 4500 RPM. That is a good steet motor.
Given it's a 302, a 289 with a similar build (carbed or EFI) would probably be about 285 RWHP (give or take 10 HP or so).
__________________ Plain Jane 65 Coupe - Scary fast (at least that's what my wife says). (SOLD 10/2012)
Feature Car in December 2010 StreetScene (the magazine of the National Street Rod Assoc)
Good example. There is more room in this build if EFi was not used, but the torque curve would not have been as good. If it was carbed and had another 1000 rpm to play with( a 280 to 290 duration cam) it would have seen 400.
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