[Cameron]

When you use the horsepower calculators that take speed at the end of the quarter mile, you are calculating rear wheel horsepower, not flywheel horsepower. GM rated their engines' power at the flywheel, not at the rear wheels. So if you are calculatiing approximately 290hp at the rear wheels, 350-380hp is probably close to the right figure at the flywheel. Alternators, fans and the drivetrain collectively take alot of power away before it gets to the rear wheels.

 

[oger]

A long time ago I read a dyno test on a stock 365HP 327 it put out about 300 actual HP. I know everone wants the 302 to have 400 HP but in stock form it just isn't there.

 

[69-ZMAN]

Its been a year since I first posted this item.... since then I found a site which had a copy of a internal Chevrolet Memo from 1967 prior introduction of the z28 option pack.... anyway, the factory guys didn't release this info outside the company... the memo states they knew they had dyno'ed the 302 @ 448 HP and had "432 HP in full vehicle dress" It went on in the 2nd paragraph to state that the engine actually put out 403.8 HP " as installed in the vehicle".

------------------
keepin' it original 69Z

 

[roger69]

About 320 HP and 290 FT lbs

NO super tuning, no headers, no cheating, no romancing the stone. Still good numbers considering its a 1950 designed motor (SBC)

 

[ckaram]

Last weekend I planned to pull the stock heads off my '68 327.

After I removed the valve covers, it said "Bitchin'" on the heads. After I saw that, I put the valve covers back on.

Forget about the 202 camel humps I just bought. I want to be Bitchin'!!!

Sorry. Couldn't help it. Just funnin'!

 

[Scott Karam]

Hey man,

I put my 69 RS Z28 on the chassis dyno last summer and it made 240rwhp and 242lbft of torque. They went to only 7200 RPMs and it seemed to still be making power but I did not want to push it any further. The motor was bone stock right down to hose clamps.
Since then, I rebuilt it .030 over, pocket ported the heads, and put headers on it with an X pipe. I'll be going back on the dyno in a few weeks to see what improvements I've actually made. I can sum my Z up in three words- TIRE SMOKING ANIMAL!

Scott Karam

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[ScottB]

Just got back from running my Z/28 on a chassis dyno. 278.2HP 295.3torque @6100RPM

 

[davidpozzi]

Thanks for the info.
Did they say what the engine HP might be on the first test?
I'm guessing the factory figure of 290 flywheel HP is pretty accurate.
David

------------------
Check my web page for First Gen Camaro suspension info:
David's Motorsports page
First Gen Suspension Page
67 RS 327
69 Camaro Vintage Racer
65 Lola T-70 Chev 350 Can-Am Vintage Racer

 

[ScottB]

They calculated the flywheel HP at 338.

 

[davidpozzi]

Thanks,
We had a fiew discussions here about what the real power rating of the 302 should have been.
I had guessed 300 to 325 hp.
Others have said up to 400+hp!
FYI,
I've got a friend who just built up a 302 with the works for road racing, roller cam, Trach One aluminum heads. It made 530 hp on the dyno.
David

------------------
Check my web page for First Gen Camaro suspension info:
David's Motorsports page
First Gen Suspension Page
67 RS 327
69 Camaro Vintage Racer
65 Lola T-70 Chev 350 Can-Am Vintage Racer

[This message has been edited by davidpozzi (edited 07-14-2001).]

 

[DjD]

Just curious if you took it higher than 6100 or just stopped at 6100 on the dyno.

------------------
...Dennis
'69 RS Convertible w/SS trim
'96 Z28SS #1679 of 2410
"The Club"

 

[ScottB]

They stopped at 6100. I've taken it to 7200 a number of times and it was still making HP from 6k to 7k. I wanted to find out how the motor was working air fuel mixture, power valve, spark plugs, timing, etc. finding out the torque and HP numbers were an incidental bonus.

 

[DjD]

338 @ 6100 and climbing!! That's good numbers for a stock mouse that will rev beyond 7000 without breaking a sweat!!

------------------
...Dennis
'69 RS Convertible w/SS trim
'96 Z28SS #1679 of 2410
"The Club"

 

[JohnZ]

I have the dyno sheets (and a videotape of ten pulls) on a 302 built to NHRA "E" Stock rules (stamped rockers, cam, stock Holley #4053, etc.) that ran 8 weeks ago on the engine dyno and since has run 11.06 in a 3300# '68 with an M-20 and 5.13 gears; obviously carefully built, but NHRA-legal. Pulls started at 5500, went to 7800 - made 425hp @ 6800 through dyno mufflers, was still pulling 419 hp @ 7800 (original GM advertised rating point was 290 @ 5800 - this one made 389hp @ 5800). The power is there, but you really have to spool it up to find it - hardly an ideal street engine for that reason, but lots of fun!

------------------
JohnZ
'69 Z28 Fathom Green

 

[jerry481]

Just thought that some might want to read this and coment: sorry it is not a Camero, but:

Just put an old 302 racing motor in to my "55" chevy, owned the car for 50 plus years, now a rat rod.

Anyways, the engine was a 283 bored to 4" with a 283 small journal forged steel crank, (Ol-skool way) 10.5 piston, 30/30 cam or better, solids, stock rockers, running 2x4's (carter carbs 350 to 500 cfms each, (no tags anymore) on an old Offenhouser intake, before China messed them up, 202 heads, headers, with a dual point mallory distributer, nonthing else would fit, with out redoing the fire wall, 411 limited slip rear end, with 60 series 14" tires , bullet mufflers, with 2 1/2" with 4' straight pipes tail pipes, Have not had it dyno as yet, but it seems like a grizzy bear.........My old Super Sun tack 0 to 8000 rpm is to small, pegs it easly...So would the 350 to 400 hp be a good guess for hp at 7500 R.P.M.

Thanks for looking,
55's Never Die They Just Go Faster,
Jerry

 

[RichardsZ28]

well it is obvious that this is an ancient tread- I can only hope that some of the posters got a dose of reality over time. First of all we should assume that those who brought up the subject want to see the highest numbers possible so they would be referring
to gross horsepower rating from 1970 and earlier. SAE and rwhp will not accomodate in the persuit of high numbers so they should be dismissed.

A 1969 Z-28 Camaro, although one of the
coolest cars from is era, has its limitations.
Some of the horsepower figures quoted were quite inaccurate.

SR fellow reasoned that because he beat 325 and 350hp 396s that that was conclusive evidence that a 1969 302 was 370-380 hp and 500 hp in SCCA trim. Wow!

My 1968 396 -325 lo-po SS 3900LBS Chevelle 3:31 R&P T-400 blew off my friends 1969 Z-28 4:10 R&P time and time again. His only chance was from a roll. My Chevelle was a high 14.70s car.

The magizines all had 1969 Zs going 15.00s with Stock ratio 3:73 and about 14.8 with option 4.10 r&p
A road and track test had a '69 Z with 4:88 gears- open headers and 10 inch slicks run 13.00

A '69 Z-28 Trans-Am racecar tuned /with open exhaust and dual quads -2 600cfm AFB
put out 410 hp at 7600 rpm- quite impressive but not 500 hp.

Keep in mind that a 1970 Z-28 LT-1 was rate at 360hp -same motor in a Corvette 370 at 6500rpm -a pretty accurate rating .

No, a stock '69 302 was 290 hp at 6000 rpm and about 340 hp at 7600 rpm.

And the old adage is applicable "Torque wins races, Horsepower ratings sell cars".

 

[Vega$69]

Comparing 302s to BBC and other engines street racing to determine which had more HP is pointless.

302s are not designed for Drag Racing and really aren't that great light to light.

My stock 69Z in 69 was very tricky for street racing. If you left too low rpm it would bog and fall on it's face. Too high and the tires would go up in smoke.

I actually ended up doing better if I launched in 2nd gear. 3.73 gears

On the track a 13s was doing good in stock form and decent driving.

In drag racing it's all about power across the band so even if it made 400 at 7500 rpm wasn't going to help win drag races.

Now from a roll race it would pull very well and consistently stronger then the ss396 Chevelles. Weren't any BBC Camaros in my town so weight could have been a factor.

I pulled the motor, went 12 or 12:5 pistons, Torker Intake, Sig Erson cam, headers, changed the gears, lakewood bars and 9" slicks. Ran a best of 11.6 on a lucky run at Lyons. I launched at 7800 and shifted at 8200.

My guess it the stock 302 is around 340-350 at 7200 rpm and the torque is probably pretty high in the rpm range which works out OK slamming around a track a 6000 rpm. Not so good for the drag strip/

 

[69z28302]

I had a 68 Z and it ran a 13.99 @ 105 bone stock (smog control). It was a RS, custom interior, M-22 rock crusher, and 4.56 gears and my 210 lbs.

After smog pump removal (my memory tells me someone stole it!), it ran a 13.71 @ 108.

As a note. I ordered 4.56s and the car came in with 3.73s. The dealer ordered a Z with 4.56s and exchanged the rear axle assembly rather that just the pumpkin. (lotta negotiating) The Z with 3.73s and 4.56s (or 4.88s) was a HUGE difference. The 302 needed a lot of gear.

I agree with the gearing. At least a 3.73 is needed. 4.10 is better.

 

[68camaroz28]

well it is obvious that this is an ancient tread- I can only hope that some of the posters got a dose of reality over time. First of all we should assume that those who brought up the subject want to see the highest numbers possible so they would be referring
to gross horsepower rating from 1970 and earlier. SAE and rwhp will not accomodate in the persuit of high numbers so they should be dismissed.

A 1969 Z-28 Camaro, although one of the
coolest cars from is era, has its limitations.
Some of the horsepower figures quoted were quite inaccurate.

SR fellow reasoned that because he beat 325 and 350hp 396s that that was conclusive evidence that a 1969 302 was 370-380 hp and 500 hp in SCCA trim. Wow!

My 1968 396 -325 lo-po SS 3900LBS Chevelle 3:31 R&P T-400 blew off my friends 1969 Z-28 4:10 R&P time and time again. His only chance was from a roll. My Chevelle was a high 14.70s car.

The magizines all had 1969 Zs going 15.00s with Stock ratio 3:73 and about 14.8 with option 4.10 r&p
A road and track test had a '69 Z with 4:88 gears- open headers and 10 inch slicks run 13.00

A '69 Z-28 Trans-Am racecar tuned /with open exhaust and dual quads -2 600cfm AFB
put out 410 hp at 7600 rpm- quite impressive but not 500 hp.

Keep in mind that a 1970 Z-28 LT-1 was rate at 360hp -same motor in a Corvette 370 at 6500rpm -a pretty accurate rating .

No, a stock '69 302 was 290 hp at 6000 rpm and about 340 hp at 7600 rpm.

And the old adage is applicable "Torque wins races, Horsepower ratings sell cars".

From what I've personally seen and read stock 302's are more like 360 HP plus. Our 302 now .03 over was built to almost completely stock spec's except for the just a tad over 10 to 1 pistons but less than the normal 11 to 1. Has a crane blueprint cam to mock the original cam. Stock heads, intake, carb, original block, crank, rods, distributor,etc. Engine was blueprinted and balanced and made 362HP at 6700 rpm. Boy this is a old thread!

 

[amy]

Well my stock 67 z 302 was dynoed when built 320 hp another 302 I did before with big cam 12.4 compression victor jr 750 carb was 350 hp so I think 350-375 hp on stock motor would b high. I have dyno sheets and these were well tuned