Can you build a real Chevy 302?

nice.....this just needed to be repeated on this thread........

 

My brother built one years ago. I remember him saying that there were two cams avalible. He found out after building his. The other was an "off road use only" grind.

 

mid-year change in 68
early was a small journal 327block/283 crank (and yes, 283's came cast or forged)
easy way to spot a forged 283 crankl is the flywheel flange is round without a notch,cast has the notch...
no 4 bolt main small journal crank 327's that I'M aware of...
the late 302's had their own crank (large journal,3" stroke forging) ands used a 327/350 4 bolt block(68-69 327's were large journal)

 

So there are "301" SBCs. Cool! OK, I got it. Still learning bout motors...and I got a way to go.

 

3 inch bore x 4 inch stroke = 301 cubic inches.
But, there's something about the sound of "302", so that's what it was called.
FWIW, 301 Ponchos have the same bore/stroke.

It is also to my understanding that small journal cranks will rev higher with more reliability. Something to do with bearing speed, and a smaller journal will have lower bearing speeds.
Don't scrimp on the oil pressure/volume!!!

Cosmo

 

301 or 302's 4'' bore 3'' stroke are great motors ,i've had my share of them . if i were to build another one i use a 350 block 4-bolt a 265 or 283 crank for less roatating weight . yes you can do it useing bearing spacers form childs&albert # MBS-327-350. the stock 283 rods will live too 8000 rpm. anything above that look out. the last one i raced an aluminum rod roller cam motor lasted 6 seasons lauching at 8500 shifting at 9000 in a 57 chevy weighing in at 3300# it went 10.80's . damm i might have to drag the car out of moth balls latter dave what fenders

 

Interesting......

 

That guy Frank....right fart smucker!

 

Educate me. Is there such a thing as a large journal 283 truck block?

 

Yes, in the 307 motors... The easiest way I found to build a 302 is find a 307, more often than naught it'll be given to you, as in freebie... Then get a 350 block, again if youcan;t get one for free you're doing something wrong... Presto, large journal 302.....

 

This is not right, the 307 has a 3.25 inch stroke, so in a 350 block with 4 inch bore you get a 327, not a 302. A 307 is essentially a 283 bore with a 327 crank, exactly opposite of the 302.

 

i have day dreamed about this a few times, I would build a "302" as mentioned above with low compression (8.5-9:1), a single large huffer, and shot of giggle juice to really get it spinning. I figured that combo bolted into a '66 Nova four door, w/ a minitub, fender spats, narrowed steelies on the front w/ hubcaps, a 5 speed and 4.56 gears, as a sleeper would blow some brains, it would have to be painted baby shit brown too...w/ a complete interior. street racin here I come.

 

www.mortec.com/borstrok.htm
useful guide

 

if you just put a 283 crank in a 327 you get a 302 but the pistons will be WAY down in the hole(.125) because of the pin hole location. you need 302 pistons with stock rods or .125 longer rods or deck the shit outta the block.

327's were small journal until 68 then they went to large journal in 69 which is the same as a 350.

unless you have lotsa cam & REALLY REALLY good heads a small block will run out of air(power) at 6000 so spinning it much above that is useless.

if you wanna spend some $$$ & go fast build a 383 with straight plug aftermarket heads & tell'em it's a 307.

 

In '68 I bought a new Z28. It had a forged crank that was not cut for an automatic. The rods were shot-peened and it had a manifold designed by some aftermarket company, can't remeber which. The two blocks for Z's were the MX and DZ. I normally shifted mine at 7200 and it would hit 8000 in fourth. That's 160 mph on I-29 north of Sioux Falls. It did hit 10,000 rpm on my Sun SST-10 tach a couple times. I currently have a 302 with a four-bolt main 0010 block and an original Z28 crank in the back of my '34 pickup. It's got roller rockers, pushrod guide plates, screw-in studs, Bowtie 1 heads, Victor Jr. intake and a real 780 Holley 3310 (not 750). It says Moroso on most of the outside pieces and also on the little sewing machine motor that drives a cogged belt to the water pump. I haven't opened it up, but I think it's a roller cam, too. I tried to sell it at one time, but nobody wanted to give me what just the heads were worth.

 

Is that the original motor you bought in the Z28 or another 302 motor you got your hands on?

 

I thought of one other thing on this 301 vs 302 discussion. In the days before calculators a lot of people used 3.14 for PI when doing the math on paper, not 3.1416. That works out to 301.44 which rounds to 301.

 

Man When I got divorced I tossed about 4 283 steel cranks Ha Ha what a bone head eh? Oh well I dont have any 327 blocks anyway but I used to run the shit out of them old 283 chevys and loved em. Got me thinking now.. I do have a set of 202 heads at my dads house. Are they any good for anything any more? Or are they worth me haulin home to make a buck on? I need gas money cause they raised it 30 cents again today Just kidding on the gas money............
Dave

 

I was told the the later 283 blocks were the same casting as the 327 and had the thick cylinder walls that allowed them to be bored to the 4" bore. They might have been the truck engines that were painted black and had the "High Torque" label on the valve covers. Anyone here know anything about this?

 

Stone is right about being called 301s Of course thats when we punched out 283s before the factory did. you won't find 301s on any factory list Carlg

 

Way back in the old days, I had a 55 Chevy 150 2 Door Sedan - primered, 301, 375 Corvette Cam, 3 speed floor shift. Everybody was running 301's. Nobody called them 302's until Chevy did in 67. Guess they wanted some difference between the factory and the backyard....Tom - restorit

 

So it was popular to build these motors?
I have talked about building one and putting it something.Everyone always tries to shoot me down.They say it makesno torque.It will be a pain to drive around town.

 

what about the pistons? does anybody make the correct piston with the correct pin location? that is the biggest road block in everyones way of building a 301.

 

Guess I gotta add my story. Had one in my first car, a 57 Chevy ragtop. Homebuilt one, that the local speed merchants built for me, Bontempo Brothers Competition. What a screamer! Great fun to drive around town, but NOT on the highway!
327 block, 283 crank, short track roller cam (solid), roller rockers, heads off a dragster, angle plug, ported and polished, 12 1/2 -1 pistons, Torker, 750 double pumper. Muncie, 12 bolt posi w/4.88's.
Not very big on torque, so in a heavy car, it's not a great idea, unless you run a lot of gear, like my 4.88's. Nothing in town could touch my car, until a guy in Linden took an older racecar 69 Camaro, w/ a 427, and put it on the street! It was the old Huckleberry Hound car.
Absolutely loved that car, wish I still had it. This was in 1978, and the car was stolen out of Raceway Park in June 79.

 

OK, we've gone on for awhile lets have a reality check. I love fantasy but someone here might be taking some of this stuff seriously. Here we go:

1. First, Rikaguilera, How did you try different "compression ratios" on the 302 you built. To change ratio you have to alter swept volumn (CID) while maintaining same combustion chamber volume, change combustion chamber volumn (different heads, deck height, or dome volumn) , or both. All of these are very costly changes to an engine that's already "built" Why didn't you go with proven specifications for your combination? This has never been rocket science, the correct combinations have been known for decades. Same goes for cams, there is a wealth of information available by just referencing the cam greinders. I don't understand your taking such an ineffecient path to arrive at a combination to power your car.
2. Bufordtjustice, You've got to be kidding about 9,000 RPM for a street engine in an Impala was it? A very svelt candidate if I ever saw one. Your talking about $10,000 to build a reliable combination and for what? Bragging rights? Suggestion, put a 6 cyl tach in it and have an orgasm every time you leave a stoplight. Make that a quick orgasm because you'll be stopping frequently for gas as I'm sure you'll incorporate at least a 4.88 or 5.14 rear gear to get that mass moving with such a weak torque motor.
I love this place, where else can we experience Disneyland and reality in such a convenient setting.

Frank

 

there are pistons out there for them- you can usually find them under NHRA stock replacement type pistons (which I guess are supposed to be factory spec etc, etc...). I think both JE and Venolia make them. The catch is they're like 11 or 11.5:1 (??) as per stock Z-28 motor

Venolia part #2821
JE part # 123567

 

This came out of a Camaro that had been drag racing at Thunder Valley in Marion, SD. Nobody in his class could come close to his times so he decided to change classes. The car was sold without the engine but he didn't want the engine used anywhere near. As I was visiting from Iowa, it was available to me. The funny things on the top of the valve covers are exhaust scavengers. A hose went to the collector and as the exhaust speeded up. it pulled a vacuum in the crankcase to help seal the rings. Also, theres a deflection plate for the scattershield between the block and flywheel. And I'm pretty sure the flywheel is 40 lbs fo high rpm launches. There's a neat Moroso pointer on the distributor shaft and a degree plate on the manifold so you can set the timing without a light. I originally bought it to get the heads but never broke it down.

 

Pistons are very easy to find. I think you will find that a lot of warehouses still have the old TRW slug on the shelf. Find someone with a mill and you can lower the compression as much as you want. While the 302 is not thought of as a torquer it is better than a 283. A fun engine in a light car.
Pete

 

"The rods were shot-peened and it had a manifold designed by some aftermarket company, can't remeber which. "

If the rods were shot peened they were done by somone other than Chevrolet. The manifold was NOT designed by someone other than Chevrolet, it was cast by Winters foundry and had that they call a snowflake with a W cast into the metal. Winters did the casting work on Chevrolet high performance intakes.

Frank

 

fab32 thanks for the info.


As for GM calling the motor a 302 when it may have been between 301 and 302 inches. It was the Muscle car days and cubic inch was kind. but the main reason I believe was because the TransAm series has a 302 cubic inch limit. Why not call it a 302 especially when your competitor (FORD) had a 302 mustang..