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Old 03-04-2004, 03:59 PM   #31
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Re: Re: Re: Re: z28

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Originally Posted by PWMAN
Both of these links show the BOSS 429 doing 13.6.
It is physically impossible that the boss 302 only made 325 HP. I would believe 325 ft/lbs of torque, but come on with cleveland heads and huge valves not to mention radical cams the 302's made 400 HP just like the 302 chevy's. What would give the edge in power to the chevy?
Both links quote the same source.....High Performance Cars. The test mule was tweeked.

I would not call the Boss 302 cam radical with only .477 in. lift at the valve, and 290 degrees duration.
Sure the duration is more than your average 302, but a 93 Mustang Cobra 5.0 motor has .477 lift.
The Boss 351 used nearly the same cam, and no one claims that it even made 400HP.
The Cleveland 4V heads are on the large side for a 302, and this cam is a compromise for the street. It would take alot more cam to get 400HP out of the Boss 302, although the heads are cpable of it.
Show me where it is documented that the street Chevy 302 made 400HP. I highly doubt it.
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Old 03-04-2004, 04:13 PM   #32
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Re: Re: Re: Re: Re: z28

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Both links quote the same source.....High Performance Cars. The test mule was tweeked.

I would not call the Boss 302 cam radical with only .477 in. lift at the valve, and 290 degrees duration.
Sure the duration is more than your average 302, but a 93 Mustang Cobra 5.0 motor has .477 lift.
The Boss 351 used nearly the same cam, and no one claims that it even made 400HP.
The Cleveland 4V heads are on the large side for a 302, and this cam is a compromise for the street. It would take alot more cam to get 400HP out of the Boss 302, although the heads are cpable of it.
Show me where it is documented that the street Chevy 302 made 400HP. I highly doubt it.
Can you prove it was tweeked?
290 duration doesn't mean anything, it's duration at .050 that counts. I don't know those specs.
The cobra 302 probably has a roller cam correct? Roller cams have MUCH more lift than any other cam and you cannot compare them.

HUH? The 351C in 71' probably made about 450 HP. It was faster than the BOSS 429 rated at 375, not to mention 450 ft/lbs. And the 351 was faster, HMM? The boss 351 had 11.7:1 compression, and you think all it made was the rated 330 HP? Please.
I've read lots of books that say although the 302 was rated at 290 HP, it was closer to 400 HP. But there was no torque of course.
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Old 03-04-2004, 04:32 PM   #33
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OK found the specs of the factory boss 302 cam. 228 duration @.050'', .477 lift and 114 ICL. So you are right that it's not very radical, but still large for 302 cubic inches.
I plugged all the data into my desktop dyno with NO porting whatsoever, canted valves/stock ports-and with small tube headers open exhaust it came out 418 HP at 6500 RPM and 405 ft/lbs at 4500 RPM. With the small tube headers and mufflers options it comes out 393 HP at 6000 RPM, and 391 ft/lbs at 4500 RPM. Even with the ''high performance manifolds and mufflers'' option it comes out with 353 HP at 6000 RPM and 358 ft/lbs at 4500 RPM.
One other thing, for some reason these engines came with dual plane manifolds. With the small tube headers open exhaust option, and a single plane manifold selected it comes out to be 459 HP at 6500 RPM and 423 ft/lbs at 5000 RPM. Add pocket porting, and it comes out to 500 HP even. You don't need a huge cam to make big HP.

So, using the exact same cam ,I put in the 302 chevy specs. Wedge/stock ports and valves-202/160 valves, 11:1 compression small tube headers open exhaust and it show 371 HP at 5500 RPM and 393 ft/lbs at 5000 RPM. Smaller valves, no cant to the valves=less power even with more compression. Now of course I'm using the same cam, I'm not sure what the actual specs are for the chevy 302.
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Old 03-04-2004, 04:43 PM   #34
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Re: 69' BOSS 302 VS Camaro Z28

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Even with the ''high performance manifolds and mufflers'' option it comes out with 353 HP at 6000 RPM and 358 ft/lbs at 4500 RPM.
Find an actual dyno test, not a cookie cutter desktop dyno guess.
Pull out some of the old magazine reviews and tests even.
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Old 03-04-2004, 05:07 PM   #35
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Re: Re: 69' BOSS 302 VS Camaro Z28

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Find an actual dyno test, not a cookie cutter desktop dyno guess.
Pull out some of the old magazine reviews and tests even.
Well the desktop dyno was pretty damn close to my actual dyno on my 273. Desktop dyno showed 321 HP, actual dyno showed 334 HP-but I had the runners smoothed and gasket matched-nothing else. The torque was off quite a bit though, it showed about 30 ft/lbs more than what it actually had.
Why don't you find the reviews? I know there is no possible way that this engine only made 325 HP. And the boss 351? LOL what a joke that it only makes 330. If it can eat the 429 for lunch, it MUST have well over 400 HP. Like I said the 429 was rated at 375 HP and 450 ft/lbs in 71'.
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Old 03-04-2004, 05:30 PM   #36
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Re: Re: 69' BOSS 302 VS Camaro Z28

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Find an actual dyno test, not a cookie cutter desktop dyno guess.
Pull out some of the old magazine reviews and tests even.
It's not really a guess, specs are specs. I know just about everything about these engines now, the only thing I didn't know before was the cam specs. Still don't know the chevy 302's. But if it is the same-
Here is the imput into desktop dyno:
69' 302 ford-4.002'' bore X 3'' stroke-301.9 CID
heads-canted valve/stock ports and valves
valve sizes-2.23 intake/1.71 exhaust
compression ratio-10.5:1
induction flow-780 CFM
intake manifold-dual plane
exhaust system-small tube headers open exhaust
camshaft-solid lifters, 228 duration @.050'', .477 lift, 114 ICL
peak HP-418@6500
peak torque-405@4500 RPM

69' Chevy 302:
4'' bore X 3'' stroke-301.6 CID
heads-wedge/stock ports and valves
valve sizes-2.02 intake/1.60 exhaust
compression ratio-11:1
induction flow-780 CFM
intake manifold-dual plane
exhaust-small tube headers open exhaust
cam-same as ford 302
peak HP-371 at 5500 RPM
peak torque-393 at 4500 RPM

71' BOSS 351C
4'' bore X 3.5'' stroke- 351.9 CID
heads-canted valves/stock ports and valves
valves sizes-2.19 intake/1.71 exhaust
compression ratio-11.7:1
induction flow-780 CFM(not sure about CFM, carb is Autolite 4300-A)
intake manifold-dual plane
exhuast-small tube headers open exhaust
cam-same
peak HP-440 at 5500 RPM
peak torque-466 at 4000-4500 RPM
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Old 03-05-2004, 07:09 AM   #37
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Re: 69' BOSS 302 VS Camaro Z28

I guess that the Desktop Dyno is a neat tool, but the hard facts are that even with open high flow headers, the Boss 351 did not make even 400HP and 400Lb-FT of torque, and the Boss 302 made less torque/horsepower than did the Boss 351.
When you are talking factory stock motors and parts, the cookie cutter guess (calculated estimation) of the Desktop Dyno software program is not always accurate. This is a case where it is off by a bunch.
The data you inputed does not differentiate between the factory iron Cleveland 4V heads of the Boss 302/352, and a head with specs like the Yates aluminum head which has smaller ports and valves than the 69 Boss 302 head, but makes it look like a 221 head in relative flow comparison.
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Old 03-05-2004, 03:18 PM   #38
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True I would need actual flow bench data to punch in to be completely accurate.
However, I'll say this one more time-The BOSS 351 was FASTER than the boss 429 in 71'-the 429 was rated at 375 HP, engines were usually underrated. Plus the 429 has 450 ft/lbs of torque. Now, you think a 351 with less than 400 HP is going to beat the 375 HP 429? NO
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Old 03-05-2004, 05:32 PM   #39
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Re: 69' BOSS 302 VS Camaro Z28

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Originally Posted by PWMAN
True I would need actual flow bench data to punch in to be completely accurate.
However, I'll say this one more time-The BOSS 351 was FASTER than the boss 429 in 71'-the 429 was rated at 375 HP, engines were usually underrated. Plus the 429 has 450 ft/lbs of torque. Now, you think a 351 with less than 400 HP is going to beat the 375 HP 429? NO
You do not get to the track much do you? For one thing, the Boss 429 was harder to launch because of the torque. 1/4 Mile ET does not always indicate absolute power when the car can not hook.
I'll say this one more time.............look at the real world, not your software and your guesses.
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Old 03-05-2004, 07:27 PM   #40
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Re: Re: 69' BOSS 302 VS Camaro Z28

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You do not get to the track much do you? For one thing, the Boss 429 was harder to launch because of the torque. 1/4 Mile ET does not always indicate absolute power when the car can not hook.
I'll say this one more time.............look at the real world, not your software and your guesses.
Well I watched a show on speed vision channel, I think it was Dream Car garage. They were talking about the 71' boss 429 mustang, but the one guy said the real sleeper was the boss 351 and it could ''eat the boss 429 for lunch''. Now I don't know if they were talking strictly at the track, but when I use those terms thats not what mean. I've never seen any boss mustangs run at the track myself, around here it's all them stupid 5.0 fox mustangs and 80's or ealry 90's F-body's. I actually like those cars, but everyone has one and i'm just sick of seeing them. Everybody always thinks their car is better and faster, blah blah blah
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Old 03-06-2004, 07:11 AM   #41
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Re: Re: Re: 69' BOSS 302 VS Camaro Z28

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Well I watched a show on speed vision channel, I think it was Dream Car garage. They were talking about the 71' boss 429 mustang, but the one guy said the real sleeper was the boss 351 and it could ''eat the boss 429 for lunch''. Now I don't know if they were talking strictly at the track, but when I use those terms thats not what mean. I've never seen any boss mustangs run at the track myself, around here it's all them stupid 5.0 fox mustangs and 80's or ealry 90's F-body's. I actually like those cars, but everyone has one and i'm just sick of seeing them. Everybody always thinks their car is better and faster, blah blah blah
They must have been talking about a '69 or '70 Boss 429, because there was no such animal in 1971. There was, however, the 429SCJ Mustang in 1971. This is one car that has not gotten enough credit in magazine reviews. The problem is that most of the reviews were either one legger CJ engines, 4 speed cars, or some combination of. There was only one test that I am aware of, that had a SCJ/Drag Pack car with an automatic. The automatic car was easier to launch, so naturally, you could get better times. The same thing is true for the Torino/Cyclone 429 cars. With the 2.40 first gear 4-speed, and the substantial weight of these cars, they were a bear to launch.
There are magazine tests for the 429SCJ Torino in the 13.60's range, and a 429SCJ Mustang even quicker. The Boss 351 had a best magazine time in the 13.80's.
The thing about a Boss 351 is that it only came with a 3.91 axle and the 2.78 1st geared wide ratio 4-speed. With over 200lbs less weight over the front tires, it was much easier to launch.
The 4-speed 428's fared better because it was a lighter engine in a lighter car, and the 428 with nearly a 4" stroke had a pile more low end grunt than did the 429 with its 3.59" stroke which was not far off of the 3.5" stroke of a Boss 351. The Boss 429 was designed for a Nascar oval, not street racing.
I have seen a pile of old Ford musclecars at both local tracks and at NMRA and World Ford Challenge races. I have personal experience with a 1970 429SCJ 4-speed Cyclone Spoiler.
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Old 03-06-2004, 08:45 AM   #42
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Re: Re: Re: Re: 69' BOSS 302 VS Camaro Z28

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They must have been talking about a '69 or '70 Boss 429, because there was no such animal in 1971. There was, however, the 429SCJ Mustang in 1971. This is one car that has not gotten enough credit in magazine reviews. The problem is that most of the reviews were either one legger CJ engines, 4 speed cars, or some combination of. There was only one test that I am aware of, that had a SCJ/Drag Pack car with an automatic. The automatic car was easier to launch, so naturally, you could get better times. The same thing is true for the Torino/Cyclone 429 cars. With the 2.40 first gear 4-speed, and the substantial weight of these cars, they were a bear to launch.
There are magazine tests for the 429SCJ Torino in the 13.60's range, and a 429SCJ Mustang even quicker. The Boss 351 had a best magazine time in the 13.80's.
The thing about a Boss 351 is that it only came with a 3.91 axle and the 2.78 1st geared wide ratio 4-speed. With over 200lbs less weight over the front tires, it was much easier to launch.
The 4-speed 428's fared better because it was a lighter engine in a lighter car, and the 428 with nearly a 4" stroke had a pile more low end grunt than did the 429 with its 3.59" stroke which was not far off of the 3.5" stroke of a Boss 351. The Boss 429 was designed for a Nascar oval, not street racing.
I have seen a pile of old Ford musclecars at both local tracks and at NMRA and World Ford Challenge races. I have personal experience with a 1970 429SCJ 4-speed Cyclone Spoiler.
Oh sorry I meant 429 super cobra jet, not boss. I get them mixed up because I was talking about the boss 351.
Anyway, I think I remember someone saying that 1/4 mile did not mean much. Oh that was you! Since the boss 351 came with 3.91 gears I would say it's pretty hard to get it to hook up too. The higher gears of the 429 make it easier to launch without spinning, what are you talking about?
Plus how do I know those times you gave aren't from ''tweeked'' cars?
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Old 03-06-2004, 08:49 AM   #43
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Re: Re: Re: Re: 69' BOSS 302 VS Camaro Z28

Quote:
Originally Posted by Mercracer
The 4-speed 428's fared better because it was a lighter engine in a lighter car, and the 428 with nearly a 4" stroke had a pile more low end grunt than did the 429 with its 3.59" stroke which was not far off of the 3.5" stroke of a Boss 351.


A ''pile more low end grunt'' combined with a lighter car would make it MUCH harder to launch. Do you have any clue to what you are talking about?
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Old 03-06-2004, 03:02 PM   #44
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: 69' BOSS 302 VS Camaro Z28

Quote:
Originally Posted by PWMAN
A ''pile more low end grunt'' combined with a lighter car would make it MUCH harder to launch. Do you have any clue to what you are talking about?

I will give you a break. I can see that you haven't had much experience in the area of big block cars on limited traction.
When you launch on factory of smaller Drag Radials, you do not want to launch at a high RPM or you will overpower the tires. The 2.40 first gear ratio combined with a 3800-4000lb car is a prescription for bog when launching at a low RPM. It is a fine line between bog and lost traction without abusing your clutch every time. This is why automatic cars are easier to launch when talking about these animals.
Do yourself a favor and get out to the tracks where the old musclecars run. It is a blast to watch, and people are pretty friendly and easy to talk to as well as willing to discuss their cars.
I have been fortunate to have seat time in both newer "stupid 5.0's" and early small and big block muscle. I have had 351C powered early Mustangs and big block powered cars. Like I said already, I can talk abouty personal experience when launching an early 4-speed powered big block car. How about you?
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Old 03-06-2004, 03:28 PM   #45
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To sum it up, the Boss 351 made more power than the Boss 302, and the 429SCJ made more power than did the Boss 351. Pretty simple concept. Bigger engine, more power. Especially when both Bosses used essentially the same heads.
You can't make horsepower without torque since horsepower is quite simply a function of torque and RPM. With less torque at the same RPM, the smaller engines make less horsepower. Basic stuff here.
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