302 chevy

**jays67** · July 1, 2009, 05:43 PM

Re: 302 chevy

Originally posted by KeithTurk

a flat tappet, pressed steel rocker motor ain't going to 8500rpm with stock valves or springs... least it won't be there long...

Sorry guys... just ain't so... Chad... your dad ain't going to tell you he did that either... 7500 maybe... but it's got something in the Valvetrain...

BIG RPM ( over 8k ) is Hard like 14 mo fo's on crack... trust me... anyone can free wing a motor to the moon... but you gots to have Piston to Valve Clearence...and remember that Compression thing we talked about... those Valve pockets gots to be there... and NONE of this is possible with a Aluminum rod motor... ( I've had one... lasted the better part of a weekend ).... It's all gots to be light and Tight...

K

I can say you are correct ssir first hand
my 283 i used to shift at 8500 and change broken rocker arms every 3 or 4 runs{was young and no money for good rollers etc...}
and my dz 302 with a factory set up other then cam {lil bigger then stock at 510} still only made round 400 ho in street trim {prolly could have squeezed more but it is a street motor } and reving it was hard on valve train parts and stock stuff did not last long
i still have it ready to run {Dan saw it in the corner of the shop when he was here} but i perfer my 355's and bigger for the street now
my race car engine is a 283 poked and stroked to 349 and we still have to rev the balls out of it and it is a jesel shaft rocker big big roller auminum rod 14:1 alky motor {yes it is a drag race engine for a 1800 puond car and we have to change rods every other year ya fun lol}

**SpiderGearsMan** · July 1, 2009, 06:20 PM

Re: 302 chevy

you need them parker-lubrite treated

**jcharliem** · July 1, 2009, 07:48 PM

Re: 302 chevy

Originally posted by Rebeldryver

Originally posted by jcharliem

Originally posted by Chad\\\\\\\'s Dad

A stock! 302 with the original 486 lift cam make about 375-400 hp so this may not be too far off. These 302's came with really good flowing heads so I would say it depends on how good the aluminum ones flow.

They were rated at 290hp (as was the Boss 302), likely for insurance purposes. A few years back, I was in the dyno room where we lit up a DZ 302 built to the original specs (pistons, cam, intake, carb... everything) for a complete matching-numbers restoration of a '69 Z/28. 360hp at the flywheel. The DZ 302 used the same straight-plug 2.02" heads as the LT-1 350. It was rumored that the angle-plug 2.02" heads (which were available over-the-counter) would add 10 - 15 more ponies.

Actually, the angle plug heads had the exact same port dimensions as the 186 castings on the Z28 and LT1 unless the plug pointed at the intake valve increased hp.

Angled-plug SBC heads point the spark plug towards the exhaust valve. That's where the hottest portion of the air/fuel mixture is. Optimum flame travel occurs at this location.

**jcharliem** · July 1, 2009, 08:06 PM

Re: 302 chevy

Originally posted by SpiderGearsMan

thats why you run a 302 with a 4 speed [that was the only way you got em ] 4.10s or 4.56 gears and a heavy foot

hear the boss 302 was an even worse street motor - but was heavenly in the upper revs

I've owned two Boss 302 Mustangs, and have driven a few 1st-Gen Z/28s. IMO, they had similar characteristics in that they needed rpm's to run like the devil... heck, that's what they were intended for (SCCA Trans Am racing!). They both came to life above 4,000rpm's in stock trim!

However, the Boss 302 always had more power upstairs. I believe that was due primarily to better flowing heads. If anyone has seen a set of Boss 302 heads, you'd know what I'm talking about. Boss heads had bigger valves than the DZ302 & LT/1 350. You can shove a beer can into the intake port of the Boss head!

Both the '69 & '70 Boss 302s had factory-installed rev limiters. If it was disconnected, the factory warranty was cancelled!

**SpiderGearsMan** · July 1, 2009, 08:11 PM

Re: 302 chevy

those boss heads were works of art

**jcharliem** · July 1, 2009, 08:16 PM

Re: 302 chevy

Originally posted by KeithTurk

a flat tappet, pressed steel rocker motor ain't going to 8500rpm with stock valves or springs... least it won't be there long...

Sorry guys... just ain't so... Chad... your dad ain't going to tell you he did that either... 7500 maybe... but it's got something in the Valvetrain...

Agree. The crazy-ass 350ci in my Chevelle has a .572/.591" flat-tappet bumpstick (w/ screw-in studs). The bottom-end is rock solid. However, the valve train is its weakest link. Although it's bounced off the 8,000rpm rev-limiter a few times on missed shifts... anything more, something upstairs will let go.

**SpiderGearsMan** · July 1, 2009, 08:21 PM

Re: 302 chevy

what are the stock eliminator guys are pulling in the revs dept ? they have to run stock rockers
maybe the bind up from stock slotted rockers ?
the guys in g-h stock are running hard with the putrid 305 - you run a 6.0 gear , you are revving like crazy in the lights

**jcharliem** · July 1, 2009, 08:46 PM

Re: 302 chevy

Originally posted by SpiderGearsMan

those boss heads were works of art

Yup, they were. The '70 Boss 302 shared the same heads as the '71 Boss 351. The '69 Boss 302 had even larger valves!!

In 1978-1980, I had a Boss 351. In stock trim, plus a Crower cam and headers... the Mustang would post consistent 12.30s at Beeline Dragway in Phoenix. That time slip was a helluva' "street ride" back in the late 70s.

TC · July 1, 2009, 08:54 PM

Re: 302 chevy

Originally posted by jcharliem

Originally posted by SpiderGearsMan

those boss heads were works of art

Yup, they were. The '70 Boss 302 shared the same heads as the '71 Boss 351. The '69 Boss 302 had even larger valves!!

In 1978-1980, I had a Boss 351. In stock trim, plus a Crower cam and headers... the Mustang would post consistent 12.30s at Beeline Dragway in Phoenix. That time slip was a helluva' "street ride" back in the late 70s.

Hey I just drove by there last week, the tower is still standing.

**jcharliem** · July 1, 2009, 08:55 PM

Re: 302 chevy

Originally posted by TubbedCamaro

Well the cat is out of the bag and Nelson Racing Engines does it again. Here is a Video of a STOCK DZ302 on the dyno, spinning 8500rpm and making 530hp.

http://videos.streetfire.net/video/69-camaro-stock-302-DZ_156232.htm

I'm waiting for DG's response. ;)

TC: I didn't bother watching the vid. There's no way a stock DZ302 is hitting 8,500rpm. C'mon... you know better. The factory-stock cam ain't going to sustain that speed. (I've driven 1st-Gen Z/28s, they fall over at ~6,500rpms.) :

**73Nova** · July 1, 2009, 09:36 PM

Re: 302 chevy

Originally posted by Eric68

Originally posted by TubbedCamaro

Originally posted by dulcich

and none of these engines will make 500 hp at 6000 rpm at 302 cubes.
-dulcich

Actually if you made 1.5 ft/lbs per cubic inch you would make a little over 500hp at 6000rpm. ;)

But only if you convert the stock O-3310 vac secondary carb to mechanical by putting a screw in the linkage. :

I don't believe you guys are still arguing with people like Turk that really know and have first hand experience with these motors!

You can argue about whether a stock DZ 302 makes 350 HP on the dyno with headers or not, but 500 with a cheap intake and carb . . . NO FREAKING WAY.

This goes back to my pet peeve -- people who think and claim they have 100 HP more than they do. You see them at car shows all the time and hanging out in the bleachers at the drag races after the first round. They're the ones with big blocks that won't race people like me with my little small block. People that never have dyno sheets or ET slips to back up their claims . . .

OK, rant over.

+1

TC · July 1, 2009, 11:06 PM

Re: 302 chevy

Originally posted by jcharliem

Originally posted by TubbedCamaro

Well the cat is out of the bag and Nelson Racing Engines does it again. Here is a Video of a STOCK DZ302 on the dyno, spinning 8500rpm and making 530hp.

http://videos.streetfire.net/video/69-camaro-stock-302-DZ_156232.htm

I'm waiting for DG's response. ;)

TC: I didn't bother watching the vid. There's no way a stock DZ302 is hitting 8,500rpm. C'mon... you know better. The factory-stock cam ain't going to sustain that speed. (I've driven 1st-Gen Z/28s, they fall over at ~6,500rpms.) :

Oh don't worry I'm not believing it either. The reason I said something about DG chiming in is because he has made comments about Nelson bumping or spiking the dyno and getting false readings out of it.

**KeithTurk** · July 2, 2009, 01:38 AM

Re: 302 chevy

This has been fun.... de-bunking the mythical 10,000rpm DZ motor is one of my favorite pass times... When folks come by my place it's a common thread due to the junk laying around...

These are fun little motors... and there is nothing in the world like listening to a 8500rpm motor pulling it's guts out on Nitrous for a full minute.... ( just sit there and stare at a clock for 20 seconds and times it by three... 60 seconds is simply mind numbing )

K

**Brian Lohnes** · July 2, 2009, 03:52 AM

Re: 302 chevy

Considering stuff like this happens in less than 10 seconds...a minute is absolutely wild.

**SpiderGearsMan** · July 2, 2009, 04:53 AM

Re: 302 chevy

revs didn't cause that = lean out did
I watched my nascar friends with turbo heads run those at 8500 all day - floating the valves on the straightaways
lets not be so brutal to the sbc

302 chevy

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