I know its posted at 290 but does anyone realy know what these motors dyno at?

As I was informed by Jim Jones at TRACO Engineering, the production 69 302 was around 385 HP @ 7000 RPM and a little over 440 HP @ 7400 RPM with re-worked production parts and an 800 cfm carb.

Yes, the little high-winding buggers were at least 50hp under rated and like Chicane said even more then that, stock.... pdq67

chicane,

that's an awful lot of an under-rating........what were those 69's doing in the 1/4 mile? i mean i realize for insurance purposes, the manu would under-rate......but by that much?

czar

I very famous 68 z28 has went I think 10.68 in a stock class. Thats slicks, 4-speed and headers. Stock with polyglass non set up right off the line was 14.6 if I can remeber. I think the L78 396 where doing 14.2 or so. NHRA rated the L78 at 425 horse so I would guess a 302 with a good tune could be at 385 or so. Strong little engine, gear it low and dump the clutch. 302's can eat alot of bigger metal for lunch but they are limited to high RPM.

This has been discussed at length before . . . here's a link to a thread that has dyno numbers and a lot of ET's in it for original Z28's - back in "the day"

http://www.camaros.net/forum/ultimatebb.php?ubb=get_topic;f=4;t=000463#000007

I personally think the stock DZ motor made 290 at 5900 as rated from the factory. The under-rated part came when you put some headers on it and spun it up to 6500 or 7 grand. Upstairs I bet the little sucker made closer to 330-340 HP. NOT crazy power like the 425 numbers I've seen thrown around but definately 40 or 50 more than the General claimed.

Just my opinion.

I think 340 HP is a good number for a stocker. Put a -140 cam in there and a bigger intake with some headers and an ignition re-curve :cool: I modeled that on DD2K once and it will flat out scream :eek:

...there is a lot of potential there.

-Mark.

Back again, I figure 330 to 340 stock and another 25 or maybe 30 or so on top of that with a set of good four tube, long headers... 355 to 370hp??

I do know that from driving my junk 301 that was sick compared to a good 302 Z-motor, it really came alive when going up top!!!

pdq67

Sorry, back again, again...

I think even GM said the L-78 was a 405hp motor stock in our cars b/c it had the poor, truck-like exhaust manifolds on it.

Drop on a set of good headers and she would go 425+ easy!!! pdq67

Well, they under rated until they could sell.....

I mean, just looking at the set-up of a stock 302, you dont really see whats there. Not to mention that the cars were sold with manifolds and headers in the trunk....!?!!

The stock 385 HP numbers were with Stahl headers on TRACO's water brake dyno, and JJ sure knows that power plant.....

Any number that was represented by a 302 that stated HP figures of 425 HP or more were those that ran the cross ram and changed the camshaft. This is supported by the book "Untold Secrets".

I know that JJ routinely generated between 440 to 460 HP from the cross ram 302 (and some other late model manifolds; post 1990) when they were sent back to TRACO for a little re-freshening.....

Smokeys #13, now owned and raced by Vic Edelbrock puts out about 470 HP with iron 492 heads and a solid flat tappet...... :eek:

[ 05-27-2003, 10:04 PM: Message edited by: chicane67 ]

any motor can have the hp raised by add ons, I really can't buy excess of 400 hp from a stock dz 302, I have owned one and yes they do wind up nice but, I had been blown off more then once by a stock 440 gtx. besides why would have anyone bought a copo if they could get more hp from a cheaper z/28? they ran quick but, I have to agree with Eric68...speedy

What does NHRA and IHRA factor them at? I think it's around 340. I've talked to people that said their 69 Z28's would hang with a 69 Corvette with the 350/350 hp engine so that should tell you it's pretty close to 350. The 302 just doesn't have the torque of a longer stroke engine.

I think the manifolds were the big hold back on the stockers. A gear change and some headers should bring that legendary top end ALIVE!!

ps. Know a guy running a 327 in NHRA G-stock that runs 11.8's with basically a DZ302 setup in a 327. Well of course he has the extra 1/4" stroke, 5000 stall, glide, and 4.56 gears :eek: but IMO it just shows that the little short stroke 4.0 bore chevy motors with the solid FT cams will really rip with a few minor changes. BTW He's actually not that competitive in the class anymore - some of the later model EFI cars are quite a bit faster.