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Discussion Starter #1
Ive recently put together a nice 347 combo for my foxbody, I dont have access to an engine dyno and Im not interested in tuning the car on the chassis dyno this time of year because up in Ontario Canada we get some chilly weather, so id just have to re tune the car in the summer. anyways, heres the setup:

E7 block 4.030, .00 decked
probe forged h beam rotating assembly, flat top 10:8 (give or take) pistons, forged
double roller timing chain
comp cams xfi stroker cam, .608/.608 248/258 @.050
short travel race lifters
ported original tfs high port heads, 2.02/1.6 stainless valves 1262 gasket, 1415 exhaust flowed 295+/- intake and 220 exhaust.
comp ultra pro mag rockers (black ones)
987 springs
race ported victor jr intake, wilson manifold big 4 hole spacer, full plenum port and 1262r gasket match, fully polished
1 3/4 headers and 3 inch exhaust
850 mighty demon carb
high flow oil and water pump

what everyones guestimation as to the hp at the wheels? driveline is 31 spline 8.8 rear with 4.56 and spool, t5 trans, alum driveshaft, 28oz steel flywheel with king cobra clutch. i say about 410hp through the exhaust rear wheel at 6500+. 375 torque.

when i do dyno the car i will post dyno sheet to see who was closest!! cheers!
 

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i say about 410hp through the exhaust rear wheel at 6500+. 375 torque.

when i do dyno the car i will post dyno sheet to see who was closest!! cheers!
I'm going to say a little less at 375 HP. Nothing bad to say but I'm just not sure about the heads and porting work and I'm thinking compression might be a tad low for that cam.

John
 

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Discussion Starter #7 (Edited)
I'm going to say a little less at 375 HP. Nothing bad to say but I'm just not sure about the heads and porting work and I'm thinking compression might be a tad low for that cam.

John
these heads flowed 280cfm intake with a 1250 gasket, i have since ported them to 1262 gasket, raised the intake ports a bit, and did some more bowl work, along with full polish. exhaust ports are big, they flower 215 before i ported them.

well look at this: my previous 306 cu in setup with 10.8:1, 2.02 e street heads ported with 265 intake 185 exhaust flow, 1 5/8 headers 230/236 .600 lift street solid roller with tight last, lightly ported vic jr and a 650 vac secondary made 347hp at 6400 at the wheels and 305ft lbs at 5000 i believe it was through a full 2 1/2 inch exhaust, mufflers, walker supercats, and tailpipes. im hoping for an additional 60hp at the wheels.
 

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engine with a 3250 rpm spead between peaks ! like to see a dyno sheet with that
As the title suggested, Guess. I did. No thought given to the no's/spread. would be odd looking tho for sure...
 

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Peak torque would be closer to 5600RPM
See above post..... ;)

Not for sure how you FIGURED that from the no's tossed into the post box, but sounds good.... :)

Why does the tq/hp ratings always cross @ 5250 rpm? or was that just an arbitrary factor used for mathematics (a common dominator of sorts?)?
 

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Why does the tq/hp ratings always cross @ 5250 rpm? or was that just an arbitrary factor used for mathematics (a common dominator of sorts?)?
Hope I don't get slammed for answering this but....Torque can be directly measured..HP is calculated from that...5250 is the constant, so to speak..Also gives proof the calculation was right...If the line crosses any other RPM equation was off.
 

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Hope I don't get slammed for answering this but....Torque can be directly measured..HP is calculated from that...5250 is the constant, so to speak..Also gives proof the calculation was right...If the line crosses any other RPM equation was off.
Holley Date Codes.

Nagh shouldnt, I ask, you answered, an me pea-brain understood!! ;)

so its the constant for the way its actually figured. makes sense, (my Common Denominator thinking was right in a sense then)
 

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[QUOTE

Why does the tq/hp ratings always cross @ 5250 rpm? or was that just an arbitrary factor used for mathematics (a common dominator of sorts?)?[/QUOTE]

Horsepower is 550 ft per sec. or 33000ft per min.
A dyno wheel 2ft in diameter so that the outer portion of the wheel is 12in or 1ft to center for ft/lb measurement.
The circumference would be 2 x 3.14= 6.28
33000/6.28 is 5252.
 

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Assuming you get a proper tune on it, should make 400+ rear wheel. Engines can be funny critters though. I've seen a 427 stroker make less than that but I keep "suggesting" the person go to a decent tuner. He's running EFI.
 

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these heads flowed 280cfm intake with a 1250 gasket, i have since ported them to 1262 gasket, raised the intake ports a bit, and did some more bowl work, along with full polish. exhaust ports are big, they flower 215 before i ported them.

well look at this: my previous 306 cu in setup with 10.8:1, 2.02 e street heads ported with 265 intake 185 exhaust flow, 1 5/8 headers 230/236 .600 lift street solid roller with tight last, lightly ported vic jr and a 650 vac secondary made 347hp at 6400 at the wheels and 305ft lbs at 5000 i believe it was through a full 2 1/2 inch exhaust, mufflers, walker supercats, and tailpipes. im hoping for an additional 60hp at the wheels.
390rwhp
 

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Discussion Starter #17
only thing im a bit concerned with is the factory block. unsure if it will hold th power and rpm of the motor/stroke without flexing or cracking. hopefully it will be ok but if not, boss block lol.

there was a setup very similar to this with afr205 heads, 11:1, a smaller hyd roller cam with 238/246 duration and .580 lift, fuelie with 42 lb injectors and trick flow R box upper that made 444rwhp. hopefully im close
 

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only thing im a bit concerned with is the factory block. unsure if it will hold th power and rpm of the motor/stroke without flexing or cracking. hopefully it will be ok but if not, boss block lol.
You have been reading to many Internet "stories" and looking at to many 'gorey' pics. The majority of that kind of carnage is NOT from just 500 or so FWHP, that is from overly boosted/nitrous shot to death combos.. NOT from N/A engines.


The only time a N/A combo will do something you are thinking could happen is if you built it from an already marginal engine block. One that has been already stressed to the max before you started putting it together.

M2C & O.
 

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Discussion Starter #20
Hey Hager, just wondering what mods other than porting you did to those E Street heads on your 306 combo?


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they got a 1262 gasket match, a bit of bowl work, ports were raised a bit on both sides and widened, really nice head, decent valve size with a small volume port, did some bowl work to the exhaust and matched it to 1415 gasket all the way down the port they flowed 265cfm intake at .600 and 188 exhaust at .600. exhaust could have been higher with a bit more bowl work. heads were fully polished except for chambers, machined for solid roller springs, and surprisingly i ran a 953 comp spring with a solid roller cam, bumped the 7200rpm rev limited numerous times and never bent a 3/8 rocker stud.
 
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