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Discussion Starter #1 (Edited)
My engine may blow up the first time it bust off but thought I would get opinions...

'67 289 engine block, World Products Sr. heads (some work done to them, well actually a lot of work done to them). 2.018 intake, 1.60 exhaust valves, custom Elgin cam by Dema Elgin, internally balanced RPM crank (289 2.875 stroke) , +18cc pistons with 61.5 cc head chambers, RPM I-beam rods, 12.8:1 static ratio, 9.91:1 dynamic ratio, Holly 650DP to be installed on a Weiand Stealth intake...

Anyone care to guess horsepower and torque?

If you need more specs, I'll post them up...

May be a month or two before I get it to the point of dyno...

Winner gets a beer, compliments of TPS...

Allen
 

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Need basic cam info like duration at .050 and lift.
 

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What's your intention for this car? Track only? Drag racer?

That carb is overkill unless you're running at 7k RPMs. It *might* be okay on the top end going WOT, but at low RPMs and part throttle, you might as well be using a small garden hose to dribble gas down your intake. Throttle response and economy will suffer, so it would be a poor choice on the street, where a 289 really needs something around 500 CFM.

Your giant valves are a similar compromise; at top RPMs, it may help your peak horsepower, but the low velocity involved with those manhole-sized 2.018 intakes is going to make it a real dog for in-town driving.

If it's a strip terror, and you're running 4.10 gears with a manual transmission, this thing should be pretty fun! Your actual horsepower would depend a LOT on the cam, as well as some other parts you haven't got listed, like your headers. I'm kind of surprised you didn't go with a single-plane manifold too, since everything else is geared to ignore low and midrange on this build, in favor of a wicked top end charge. That being said, the Stealth should probably still do okay for you, with at least a 1" open carb spacer on it to give you a bit more plenum volume and allow some pulse transfer between sides. In fact, with your oversized carb, the Stealth may end up being a slightly better choice for your 289. It's probably a close call.

Assuming you went with a 'racy' cam designed to put you around 7k (you didn't mention roller lifters or rockers, so that's probably end of the line if you're running flat tappets) I am going to take a wild guesstimate and say you're going to be around 350 flywheel horsepower, with really horrible street manners and mileage that will even make 500 Caddy drivers feel economical.

Your *peak* horsepower might be decent, but average horsepower will probably be way down, due to the short stroke and corresponding lack of low-end torque, along with the high-rpm-only goodies on this engine.

I am guessing you meant domed pistons (-18cc) not dished (+18cc) to get that compression ratio; I hope they are well matched to your heads so you can take advantage of quench, or this thing is going to need avgas to run!

Good luck, and hope it's wicked fun. =)
 

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Knowing this is a track car engine from your build topic, Im going to assume since you've gone shaft mounted rockers that 7K+ rpm is where you spin this thing. I'm going to say 419hp at approx 6900 rpm on an engine dyno. No comment on the torque.
 

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@Lightning - Cheater. lol

Yeah, that does change a lot - this sounds like it's not just a "Well, I heard this was a good part!" build. =) Let's hope your results ARE higher than my estimate, if that's what this car's for! With supporting valvetrain stuff to take it more to 8k, 400 horses is a cinch.

Slightly off topic - my friend Tom used to build dirt track racer engines that ran alcohol. One of them got an old Port-O-Sonic Offy intake that he'd tinkered with, and the darn thing spun over 10k, making obscene amounts of power. I don't remember the numbers anymore, so I won't try to make some up to sound cool, but it sure was amazing.

We discovered a lot of interesting things with that motor, including the sound an alternator fan makes when its cooling fan balloons so hard the connecting bits on the star come apart...

Good times.
 

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The engine is going in fully prepped open track car. The engine will live most of its life between 3500 and 7500 RPM. The cam is a custom grind from Dema Elgin specifically for his heads, 289 stroke, and compression range. The intake manifold is a rules requirement. The engine is a very well planned and pieced together product.

Based on what I know from recent experience I’d say 410 HP and 385 T.
 

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289

AllenTurn, we need a bunch more specs. What boosters does the carb have ? what is the lobe profile on the cam and what is the lift and duration and separation ? The carb is NOT too big, the valves are NOT too big, and the Stealth pulls just fine, even at idle, but the cam in this combintion is a make or break deal. Booster impact is huge. Whatcha got ? If you don't know, your builder should. If he doesn't know either, then you have a problem. LSG
 

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Discussion Starter #10 (Edited)
Duration 300 Intake/284 Exhaust 253/248 @.050
Valve lift is .556 Intake .532 exhaust
Intake Opens 43* Closes 67*
Exhaust Closes 28* Opens 68*
Exhaust centerline 110
Intake centerline 102

On his chart he has 106* + 40 written in above TDC

I think Patrick summed up everything else fairly well...

Allen
 

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Discussion Starter #11
AllenTurn, we need a bunch more specs. What boosters does the carb have ? what is the lobe profile on the cam and what is the lift and duration and separation ? The carb is NOT too big, the valves are NOT too big, and the Stealth pulls just fine, even at idle, but the cam in this combintion is a make or break deal. Booster impact is huge. Whatcha got ? If you don't know, your builder should. If he doesn't know either, then you have a problem. LSG
The carburetor has not been purchased, yet...

Allen
 

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Discussion Starter #12
If it's a strip terror, and you're running 4.10 gears with a manual transmission, this thing should be pretty fun!
For the record, the rear is a Quick Performance 9" Yukon Nodular center section with 3.70 gears and a 4 speed close ratio toploader rebuilt with a David Kee road race kit...

Allen
 

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Duration 300 Intake/284 Exhaust 253/248 @.050
Valve lift is .556 Intake .532 exhaust
Intake Opens 43* Closes 67*
Exhaust Closes 28* Opens 68*
Exhaust centerline 110
Intake centerline 102

On his chart he has 106* + 40 written in above TDC

I think Patrick summed up everything else fairly well...

Allen
I’m anxiously awaiting your dyno results. Sounds like a very well thought out build. I’m going to say 433 hp and 401 tq
 

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428 and 390, sticking with Ford numbers.
 

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World Products Sr. heads (some work done to them, well actually a lot of work done to them). 2.018 intake, 1.60 exhaust valves

Anyone care to guess horsepower and torque?
I'm just curious about the intake valves; why the slightly undersized big intake valves? A Windsor Sr head will take a 2.02 valve, correct?

My guess would be 435/375 on hp/tq.

Sent from my LG-D631 using Tapatalk
 

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Discussion Starter #20 (Edited)
I'm just curious about the intake valves; why the slightly undersized big intake valves? A Windsor Sr head will take a 2.02 valve, correct?
.002”...there might be a difference in actual versus advertised there. 2.02” just rolls of the tongue a little easier.
When the heads where flow tested, the valve sizes were given on the test sheet. I'm trying to pass along as many specifics as possible...

When I bought these heads I was given the information that "11.25 hours of porting and ultraviolet wet flowing from Top Kat Engineering who did development work for the IMSA GTO Mustangs in the mid 1980's"

Allen
 
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