ZD75blue

Just me again guys... :jester

I started pondering a 302 once again, and got to thinking... if they rev to 9 grand what heads to they use?

And if you cut the rotating weight on say a 350 and increased the flow, could you not take it to 9k too?

Just throwing around some ideas... any of you guys have any on these mighty mouse motors?

4 speed + 4.56 sounds like the key to a 302 :cool:

ZD75blue

I guess i need to add... talk me out of it to that :jester

DJ Dep

My friend...you are talking my language. 302 is my FAVORITE small block.
It's the ONLY small block I would consider building for that matter.
Here's some info you might like. Not written by me but off a Z-28 website:

The Z/28 302 engine was rated by the factory at 290hp. Although everyone says that the engine was underrated, I have not seen any tests done to determine the actual horsepower. Estimates have ranged from 300 hp to 500 hp. The numbers that have been documented come from the actual Penske/Donohue race cars.
Pat Ryan of Unfair Advantage Racing owns one of the original 1967 cars. He still races it it the Sports Car Vintage Racing Association. The engine, as prepared by Traco engineering, puts out 398 hp at 6,800 rpm. In 1968 the Traco engines put out varying horsepower in different stages of tune, but I have seen the following numbers: 441.5 @ 7,400, 419.5 @ 6,800, and 458 @ 7,100. These figures were taken with the single four barrel setup.
So how powerful was the production 302? Probably around 350-400 horsepower would be a good guess. No bad from 302 cubic inches!
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Not sure on the head question but I suspect they used 2.02 straight plug heads. That was back in the late 60's and I THINK that was the best they had.
I was only 18 when the 1967 Z-28 came out and I had other worries on my mind at that time (think back to what major event we were involved in back then). You might check the book How To Hot Rod Small Block Chevys for more details on the 302 engine. I think they even have the pictures and part numbers for the two Holley 4bbl cross ram manifold in there.

Don't look to me to talk you out of liking that engine. It ain't worth crap for torque, but it LIVED at high RPMs, and that's where it made the horsepower.

Dep

Vetterodder

The DZ302 used the same heads (except for being drilled for accessories), cr, and cam as the 365hp 327. The 302 had a better intake manifold and a larger carb (780vs585) but had less efficient exhaust manifolds and pipes. Assuming a similar hp/cube ratio as the 365hp 327, the 302 would have come in at about 340hp gross, but a little more was likely due to greater volumetric efficiency. Keep in mind that the 302 was created in order to allow the Camaro to race in a class that had a 5 litre limit and not because GM believed that less cubes would make more power.

Back in the late 60's and early 70's, I was drag racing most every week and there were no shortage of Z28's there. Typically, factory stock ones with standard 3.73's ran mid to high 14's. The same cars with 4.56's and 4.88's ran low 14's, high 13's. With headers and slicks, times dropped into the low 13's (I ran a just such a 69 Z28 of a friend to 13.3 my first time in the car). Add 48 ci to the same motor and you'd get into the 12's. All those guys stroking their engines to 383 aren't crazy, they know that more cubes mean more power :)

Schmucker

My dad's '64 has a 302. He spent 90 hours porting the heads to get around 550hp. It has 13.5:1 compression, tunnel ram, and two 600cfm Holleys. He said he would rev it anywhere between 9k and 11k off the line. It didn't make as much power up there, but as soon as the clutch was engaged it would be right in the power band. The engine is mated to a 5 spd Doug Nash with a Mr. Gasket inline shifter. The rear gears in his 9 inch nodular is 5.87. He has a set of 6.50s that he is supposed to be running. He has 14inch slicks on the car. You should easily be able to get a 350 to 9k, but setting it up to make power there is a different story. The only really problem you have once you start getting closer to 10k is breaking valvesprings, but that is an easy enough fix. The reason my dad used a 302 was because the class he wanted to run in had a limitation on displacement. If not, he would have ran a 350, he knows more displacement is better, until you go with a big block, then you're just screwing everything up. Did I mention his car does 3ft wheel stands off the line? Then just a little 1 footer when he goes into 2nd...

Rocket Ron

302 is/was a FORD engine ;) . Build a 383 and put a 302 decal on the air cleaner. Only you and the machinist will know and you can always tie up that loose end. :blueangel:

PROSOUTH

Add 48 ci to the same motor and you'd get into the 12's. All those guys stroking their engines to 383 aren't crazy, they know that more cubes mean more power :iagree:

Guys, I had one,a '69 real Z/28, get over it, add 48 C.I. and then what ever your daddy did to it and then watch it go !!!!!!!!!!!!!!!! The best thing that ever happened to mine was when the rods and crank let go and I changed it to a 350, wish to heck there had been a 383 back then, it would have screamed................

Do you really think it is a FORD Conspiracy and that all of the Liberal Medias are keeping the real "TRUTH" of the 302 a secret from "US" ?........... 302, Chevrolets Urban legend.....JIM :lol:


[Modified by PROSOUTH, 11:51 PM 12/14/2002]

Schmucker

If the '67 Camaros had the 302 then they beat Ford to it. :D

mapman

ZD75blue,

I think the problem is going to be HEAT (piston speed) rather than rotating weight or flow.

I believe the 302 used a 3" stroke crank from a 283, and the 350 uses a 3.48" stroke. That 16% longer stroke, at high rpm, would translate into some VERY high piston speeds (heat). The 302 at 9k rpm is probably on the edge, the 350 might be over the edge at 9K rpm.

You see this difference especially in motorcycle engines. High reving sport bike engines have relatively short strokes, but this stroke/rpm combination generates a tolerable piston speed. A Harley Davidson in contrast, has a relatively low reving engine, yet it has quite a HIGH piston speed because of its long stroke. In both cases, designers matched their engine design to the engine's intended use.

ken markusa

Here's a better combo bowtie block 4.155 boreX 3.23 stroke crank = 350 cubes. Big bore to unshroud the valves stroke roughly same as a 327 so it will accelerate quickly good compression with a flat top piston 11.5 depending on the size of the chamber and an excellentrod ratio with even a stock length 5.7 rod easy 500 hp with right heads and cam. HOWEVER if you want to RPM up to GOD'S doorstep you must have absolutely the best parts and machine work because rpm KILLS motor the effect of 4000 rpm vs 8000 rpm isn't doubled it's squared ( bet you wish you were paying attention math class now instead of doodling Corvettes, AW what the hell we all were :D ) so good parts are essential. Unless you are building for a specific pounds per cubic inch class bigger is better ALL things being equal a bigger motor will make more power. Here's a tid bit for all your EURO/ JAPANESE sportscar buddies who think that the pushrod engines in Corvettes and NASCAR etc. are equal to farm implement machinery, a NASCAR 358 ci Chevy and a Formula 1 ( insert name that will give most grief here) engine make about the same HP 750-800 the F1 engine being roughly half the size of the Chevy has to spin at twice the RPM 18,000 vs 9,000 to make the same HP so their volumetric efficiency is the same, after all an engine is only an air pump air in air out, and can only displace about 110% of their volume on a really good race engine. :rolleyes: there a runon sentence i was day dreaming during english class too :D .
Ken
P.S. The above combo parts can be bought second hand at really good prices especially cranks even new , check the Crower garage sale the drawback is that the cranks generally have a big block snout and small sized mains plus the rods are cut for 1.88 Honda bearings. Hope this helps
:cheers:

Larry B.

302's were easily made from 283's by boring to 4" . This made a 3" stoke X 4" bore.... BTW...The Ford 302 (aka 5.0L) is the same. They(Chevy 302's) were popular hot rod choice in the late 60's. Short stroke engines rev very quickly and are a good choice for light cars with low gearing, however, they do not have a lot of torque at lower rpm. The "real" 302 had a fairly radical mechanical lifter cam and I believe a Holley carb and an aluminum intake. They also had an 11:1 compression ratio. Things changed over the years and one of the things that affects our engines today is low octane fuel. Engines designed for 100+ octane run poorly on anything less. Fuel injection, high tech computers and superior internal parts and machining make todays engines perform much better than the engines of the 60's. Sure there were some great muscle car engines but they needed constant tuning, 100 octane fuel, got 8-12mpg AND every race was a toss of the coin if the engine would blow up or not. Also you couldn't (or wouldn't want to)drive a car with a 4.11 or 4.56 rear ratio on any length of trip. Were those really "the good old days"? It WAS a fun era though... :cool: :chevy


[Modified by silvervetteman, 6:49 AM 12/15/2002]

ZD75blue

What made me woneder about the longer stroke... more space for the piston to travel, but i guess in turn more contact with the rings... less heat trapped in the piston.

What are the stock rods good for? 4000 feet a min, 5k?

Then the last question... cough... are they fair with gas milage on a semi-street engine? :crazy:

ZD75blue

Ok... i was talked out of the 302...

283 crank + rods + pistons = 302

400 crank + rods + pistons = 383?

What got me thinking about it, was Smokey Yunkics book... he said odd ball bores and strokes area waste of time... but the 383 is getting alot more popular :jester

Does anyone havea dyno sheet for a road going 302, 327, 383... 400 i dont think i want to mess with just yet, overheating probs...

Larry B.

Besides that... A 283 crank has smaller diameter journals so it wouldn't work in a 350 block. Late 302's had a large journal crank but they are hard to find... :chevy

ZD75blue

So a large journal aftermarket 283 crank would float the boat... if they make such a beastie :smash:

Larry B.

There were no large journal 283's so it wouldn't be listed that way.. It would be a large journal 302 crank... :D ;)

DJ Dep

In order of appearance:
Schmucker: I need to meet your Dad. He sounds like a cool guy that thinks EXACTLY like me. Is his age in the 50's? Just a guess :) His car sounds like an awesome setup and reflects what a 302 is REALLY capable of. Thanks a ton for making that post. I enjoyed the heck out of reading about it. A 302 PROPERLY set up with the right tires and performance options IS capable of some amazing power. Your Dad helped prove my point and justify my admiration of the motor. Please thank him for building a true hot rod motor.
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Rocket Ron:
Quote:
"302 is/was a FORD engine. Build a 383 and put a 302 decal on the air cleaner. Only you and the machinist will know and you can always tie up that loose end"

HA! HAHAHAHA! ROFL. Oh that is RICH. :lol: :lol: :lol:

If you want to talk numbers, 383 is/was a MOPAR ENGINE. As in Plymouth Roadrunner, Dodge Super Bee, Chrysler New Yorker, etc., etc.
Cubic inch numbers mean NOTHING. Tell people you have a 327 or 283 if you're embarassed to tell them it's a 302. Of course, if you have the cubic inch fetish and just have to impress your pals, tell them it's a 427 or 454. Just don't raise the hood or start the engine. If you don't display wall-to-wall engine or make the ground shake at idle, then they'll know you're fibbing :D

Even better and less embarrassing: tell them it's a 1968 Z-28 engine. If they are Chevy folk, they will know what you mean.
Any putz can bore and stroke or BUY a crate engine that was bored and stroked and makes more power. It takes a REAL hot rodder to wring the maximum amount of power out of a 302. As in Schmucker's Dad above.
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PROSOUTH: See Schmuckers post above. And there WAS a 383 back then. It was in a Plymouth Roadrunner. It would have been an interesting installation in your Camaro. I think both camps would have burned the car to the ground :D
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mapman: quite true about the heat. Also the longer stroke cuts the RPM limits because the heavier mass has problems staying together at the levels of the 302's RPM. What people don't understand, or don't WANT to understand, is that the 302 was made to LIVE at 6-8000 RPM. Not just REACH that level. I'd like to see ANY of these crate motors run a Trans Am Race where
they STAY at those RPMs through the whole race.
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ken markusa: What you say is true as far as the 302 Z engines not having torque. They weren't MADE for torque!!! Torque worship seems to be a fascination that was discovered when horsepower numbers shrank. Can't brag about horsepower any more so you brag about huge torque figures. The 302 Z engine was NEVER made for torque. It was made for producing power AT HIGH RPMs. Who needs torque when you can get 458 horsepower @ 7100 RPM? Just let your foot slide off the clutch and then power shift in the RPM band the engine was DESIGNED for. Presto...you win :D

Quote:
"Things changed over the years and one of the things that affects our engines today is low octane fuel. Engines designed for 100+ octane run poorly on anything less."

Also true, but, it is NOT impossible to find gasoline of 100-104 octane. It's not as EASY to do...but the stuff IS still out there. Understand that the 1967-69 Z-28 was a true RACE CAR that was sold for street use. It was NOT a car MADE for street use. You couldn't order air conditioning or automatic trans for it. You got a stick shift and sweated your butt off in the summer, but in compensation you had a car that ran VERY well. I guess we were pretty hard core back then as compared to folks today that can't live without power windows and a sunroof.

"Fuel injection, high tech computers and superior internal parts and machining make todays engines perform much better than the engines of the 60's. Sure there were some great muscle car engines but they needed constant tuning, 100 octane fuel, got 8-12mpg AND every race was a toss of the coin if the engine would blow up or not."

All true EXCEPT for the "every race was a toss of the coin if the engine would blow up or not." If you pushed your engine beyond it's limits it WOULD let go. So would ANY of today's engines. And you WON'T get good gas mileage with an engine designed for racing. Why not? BECAUSE it was designed for racing.
What kind of mileage do you think NASCAR motors get? Mileage meant NOTHING back then. To a true racer it STILL means NOTHING. SPEED is EVERYTHING...mileage be damned :D
Back in the 60's we made horsepower from the seat of our pants. No computers or other fancy gizmos to help us. I think we did pretty good with the 302 Z-28 and the 427 L-88.

One more tidbit. The NASCAR comment. You are quite right about the 358 making tons of horsepower and living at 8-9000 RPMs. It's an amazing motor. But you left off one little item. It's COST. Anyone fantasizing in high school (I couldn't draw so I dreamed) or on this board of getting their crate engine to reach and STAY at 8-9000 RPM and producing 800 horsepower like the NASCAR motors do is out of luck. There is a lot more to that engine than just an Edelbrock manifold with a Holley carb with headers. And the cost...figure roughly a $10,000 crate engine TIMES FOUR! Better start buying lottery tickets if that's your goal :D
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ZD75blue:
Quote:
"Ok... i was talked out of the 302..."

Gee...that was sure easy. Did you just IGNORE Schmucker's post or are you now infatuated with the Mopar 383 number? The 383 is popular because it is a nice friendly street engine that won't produce scarey performance like Schmucker's Dad's car. It runs on pump gas. It's easy to maintain. It gets 1000 miles to the gallon. In modern day lingo-speak it's "user-friendly". How can you go wrong? By all means buy a Mopar-sized Chevy/Roadrunner engine. Just don't race Schmucker's Dad :)
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To the crank and journal worriers...all that stuff is still available from aftermarket sources (most crank grinders stock old factory-sized parts, or can easily build them). Ditto for the cam, pistons and rods, which should be available from TRW and other sources. What would be harder to obtain would be the factory dual quad cross ram manifold, carbs, and linkage. Hard to find and expensive to buy. ZD75blue may have been talked out of building a 302 Z-28 engine, but the more we have this discussion, the more I am tempted to build one. High compression, tune it every week (big deal...so you miss an episode of "Taken"), noisy lifters, and all. Then just drop it into one of those Cheetah kit cars and OH MAN! :D

Dep
P.S. If I offended anyone with my replies...Mopar has a 383 complaint department :lol:

PROSOUTH

PROSOUTH: See Schmuckers post above. And there WAS a 383 back then. It was in a Plymouth Roadrunner. It would have been an interesting installation in your Camaro. I think both camps would have burned the car to the ground

Cute DEP..............

I understand your fetish with the 302, and I am not saying that it was a piece of junk, just that there was a better way. The 302 I had was a production model. The references you keep using are Trans Am. Big difference!

Someone else has tried to explain the Horsepower vs Weight to you also. The 302 had very little torque and was Bit@* to drive on the street. A production 302 in a 3400 lb street car is a lot different than a race version in a stripped down T/A Racer.

As far as Racing By The Seat of Out Pants? Yeah, I know all about that too.

The 383 Mopar I'm very familar with. I owned several Mopars and raced a 440 Pro Duster for several years while owning a Corvette to drive.

I have no reason to attempt to disgrace a 302 or it's followers. It's just that the best thiing that ever happened to mine was "The Day The 302 Died" So Bye Bye Miss American Pie...................................:s eeya

DEP, Why don't you just go ahead and build a 302?:rolleyes: Chevrolet that is :D and see for your self. Then when the little bugger lets go replace it with a 350 or 383 Rotating Assembly and not change anything except the Jets in Carb and maybe a matching gear ratio? :yesnod:

302, URBAN LEGEND or Hidden from us by the Liberal Automotive Media? :lol:

DJ Dep

PROSOUTH: First let me thank you for not "going off" on me. That seems to be a popular pastime among the mouse motor afficionados :D

Yes...the Trans Am cars no doubt were souped up even more than the factory racers. Certainly no argument there. But think about this...IF you souped up a 302 with CURRENT performance technology, not the high tech computer crapola, but aluminum heads and advanced cams (not sure you could improve on the cross ram manifold though), just THINK about the power you could make. Look at Schmucker's post again. LIFTING THE WHEELS with a 302!!!!! Uheard of in the 1967-69 Zs.

What do I care about how it drives on the street???? I have a 2002 Monte Carlo SS and a 1998 C5 to drive on the street. We are talking about a RACE engine here. Not some detuned 9-1 stroker. I'll FIND the high octane gas for 11 or 12-1 compression. I'll gladly sacrifice an hour and the cost of valve cover gaskets to adjust the lifters every week. I'd happily live with 3 miles to the gallon. It would be WORTH all that for the performance it would reach.

Quote:
"DEP, Why don't you just go ahead and build a 302?"

Oh man...you are TEMPTING me. I could do it for PEANUTS compared to what I have planned for my '72 (a Reher-Morrison crate engine in February...cost $10,000).

Let me say this...if I DIDN'T have the '72 already, I'd buy a Cheetah kit car and build a 302 for it in a heartbeat. The combination would be scarey-fast and pretty much unbeatable.

Dep
P.S. Do the 383 crate motors go beep-beep? ;)

Stingraycrazy

302's :thumbs: are one of my favorite motors but lets go to the next step on big bore short stroke small blocks.


Crazy's big bore short stroke HP Recipe...

Ingredients:

One 400 2 bolt machined 0.030 over with 4 bolt billet splayed mains.

One 327 large journal forged crank with one piece spacer main bearings.

Eight 6.250" H Beam rods bushed for floating pins. http://cgi.ebay.com/ebaymotors/ws/eB...tem=1874679878

Eight (406 6" rod 1.125" compression height) pistons with pins. http://cgi.ebay.com/ebaymotors/ws/eB...tem=1873561355

One solid roller cam set 250/264 dur @ 0.050" with 0.650+ lift with a 110 lsa

Mixing instructions:
Balance well, blueprint the rotating assembly and insure proper torque specs are meet during assembly. Gaskets too taste, top with big valve aluminum heads.

Servings:
Around 600hp @ 11:1 compression on pump gas... :crazy: