during my younger years 72-75 (high school) guys were building 302's right and left. one of my fondest memorys of hot rodding was riding in a 63 chevy 2 4 speed. the owner was one of the cool cats in town and we were on bicycles. He asked my buddy and I if we wanted a ride. well back to my question. it seams now pistons are 500 plus bucks. i am sure back then rodders building 302's were not shelling out that. need a history buff to explain.

How much history do you want????
You wanna go back to the 50s?
In the beginning, God created th------------------------no, no, no, that's another story!
In the late 50s (283 came out in 57), some guys were boring out the 283 to .120 over. This produced a 301 cubic inch motor. MANY, but not all, 283s would punch out this far. Back then, machine shops did not posess the capability to sonic test a block for cylinder wall thickness. Boring a 283 this much was basically a crap shoot. :thumbsup:
For the guys that could afford this kind of an engine rebuild, this was fairly common (this displacement was developed by true hotrodders------------NOT Chevrolet!!!). As far as I know, .120 over pistons for a 283 were only available as forged versions. I've never known of a .120 over cast piston. Also, back then, the "HOT" cam from Chevy was the 097 "Duntov" solid lifter cam which was used in the FI and 2x4 engines with a solid cam. In the day, you were "special" if you had a Duntov cam in your ratty Chevy! The 301 Chevys were the king of performance small blocks until the 327 came out in 62, although, because of its short stroke, the 301s could still out wind a 327. Nothing has changed in that respect.
Then, in mid-67, Chevy (per Vince Piggins in Chevy's performance engineering group) took a 327 block, stuck a 283 crank in it, put domed 11.5:1 forged pistons in it, stuck in the ole "30-30" solid lifter cam (from the mid-60s solid lifter 327s with FI or a Holley), used the 2.02 design heads and designed a VERY good flowing hi-rise alum intake with a 780cfm vac secondary Holley. The result was the original 302 Z/28 screaming engine------------------------rated at 295hp-------------------ya, right!!! When torn down, totally balanced and blueprinted and a few "minor" mods by the Grump ("Grumpy" Bill Jenkins), the 302 could develop almost 500hp. Of course, that was at a bazillion rpm! The FIRST 302 was a small journal crank and pressed pin version. In 68-9, the 302s were the big journal version with floating pins. The 67-68 302s had chrome valve covers, the 69 302s got the same finned alum valve covers as the 69-later Vettes. The 70 Z28 engines went to 350 cubes (and a different profile solid cam).
The 302s were ONLY, ONLY, ONLY a Z/28 (Camaro) engine. Period! The 70-later Z28 (notice there is a difference between Z/28 and Z28) engines and Corvette LT-1 engines were exactly identical----------------no longer unique to the Camaro! :sad:
Sooooooooooooooooo, Mr. famous Vince Piggins at Chevrolet engineering was given credit and many accolades for developing such a fantastic engine which met SCCA racing requirements, that already had long ago been built and proven by multiple hotrodders around the country.
And, to answer your original concern about pistons, this is a single application requirement for a piston (very limited demand=hi price). I don't know if std bore pistons are available for the 302, but oversize pistons are. They are available ONLY (as far as I know) in a domed, forged version that produces about (depending on combustion chamber size which was originally about 64cc) 11.5:1 or 12.0:1 compression ratio. There used to be some pistons available that would produce about 13:1.
I guess I better get off of my soapbox and shutup before GM files a law suite against me for slandor. :p

How much history do you want????
You wanna go back to the 50s?
In the beginning, God created th------------------------no, no, no, that's another story!
In the late 50s (283 came out in 57), some guys were boring out the 283 to .120 over. This produced a 301 cubic inch motor. MANY, but not all, 283s would punch out this far. Back then, machine shops did not posess the capability to sonic test a block for cylinder wall thickness. Boring a 283 this much was basically a crap shoot. :thumbsup:
For the guys that could afford this kind of an engine rebuild, this was fairly common (this displacement was developed by true hotrodders------------NOT Chevrolet!!!). As far as I know, .120 over pistons for a 283 were only available as forged versions. I've never known of a .120 over cast piston. Also, back then, the "HOT" cam from Chevy was the 097 "Duntov" solid lifter cam which was used in the FI and 2x4 engines with a solid cam. In the day, you were "special" if you had a Duntov cam in your ratty Chevy! The 301 Chevys were the king of performance small blocks until the 327 came out in 62, although, because of its short stroke, the 301s could still out wind a 327. Nothing has changed in that respect.
Then, in mid-67, Chevy (per Vince Piggins in Chevy's performance engineering group) took a 327 block, stuck a 283 crank in it, put domed 11.5:1 forged domed pistons int it, stuck in the ole "30-30" solid lifter cam (from the mid-60s solid lifter 327s with FI or a Holley), used the 2.02 design heads and designed a VERY good flowing hi-rise alum intake with a 780cfm vac secondary Holley. The result was the original 302 Z/28 screaming engine------------------------rated at 295hp-------------------ya, right!!! When torn down, totally balanced and blueprinted and a few "minor" mods by the Grump ("Grumpy" Bill Jenkins), the 302 could develop almost 500hp. Of course, that was at a bazillion rpm! The FIRST 302 was a small journal crank and pressed pin version. In 68-9, the 302s were the big journal version with floating pins. The 67-68 302s had chrome valve covers, the 69 302s got the same finned alum valve covers as the 69-later Vettes. The 70 Z28 engines went to 350 cubes (and a different profile solid cam).
The 302s were ONLY, ONLY, ONLY a Z/28 (Camaro) engine. Period! The 70-later Z28 (notice there is a difference between Z/28 and Z28) engines and Corvette LT-1 engines were exactly identical----------------no longer unique to the Camaro! :sad:
Sooooooooooooooooo, Mr. famous Vince Piggins at Chevrolet engineering was given credit and many accolades for developing such a fantastic engine which met SCCA racing requirements, that already had long ago been built and proven by multiple hotrodders around the country.
And, to answer your original concern about pistons, this is a single application requirement for a piston (very limited demand=hi price). I don't know if std bore pistons are available for the 302, but oversize pistons are. They are available ONLY (as far as I know) in a domed, forged version that produces about (depending on combustion chamber size which was originally about 64cc) 11.5:1 or 12.0:1 compression ratio. There used to be some pistons available that would produce about 13:1.
I guess I better get off of my soapbox and shutup before GM files a law suite against me for slandor. :p

Your 100% correct, Your showing your older age now.

As to the pistons i think Keith Black makes some, to get 13:1 compression out of a 302 your talking a .450"+ tall dome with small 62cc-64cc chambers, 58cc would help allowing you to use a smaller dome

My 327 has had an old set of the GM/TRW high dome race piston, they had these out for 302/327 and 350 in the later years and i still think the 350 piston is available today

The 301 was a fantastic engine in a light car, 4 speed, and a lot of gear! I had a '66 Nova SS with 4.10 gears and the thing flew. But to answer your question, that combo is not very popular any more so parts are low production and expensive.

In the late 50s (283 came out in 57), some guys were boring out the 283 to .120 over. This produced a 301 cubic inch motor.
:p

UM,Tom ,wasn't it .125 over ?

UM,Tom ,wasn't it .125 over ?

Back then, the pistons were listed as .120 oversize for a 283. With a .120 bore to a 283, that prodiced 300.83 cubic inches, and everyone called it a 301.
The 302 Z/28 engine has a true 4in bore (.005 bigger than a .120 over 283). When you calculate that out-(r2 x pi x 3 x 8cyl), it =301.58, or rounded off to 302.
So that is how the difference was derived between the 301 and 302, same-same in everyone's book. It's simply splitting a nano hair.
If you STARTED with a 283, and bored it .120, you have (or had back then) a 301-------HOME BUILT BY HOTRODDERS!
If you START with a 327 (true 4in bore) today, and put a 283 crank (3.0in stroke) in it, then you have a 302---------------BUILT BY CHEVROLET AT THE FACTORY.
So, for us old timers like me, when someone speaks of a 301, we automatically know that is a BORED 283 block. If you speak of a 302, we automatically know you are referring to a block that had a 4in bore to begin with.
Is it peecan or pecon, tomatoe or tomahtoe, potato or potahto? :confused:

Back then, the pistons were listed as .120 oversize for a 283. With a .120 bore to a 283, that prodiced 300.83 cubic inches, and everyone called it a 301.
The 302 Z/28 engine has a true 4in bore (.005 bigger than a .120 over 283). When you calculate that out-(r2 x pi x 3 x 8cyl), it =301.58, or rounded off to 302.
So that is how the difference was derived between the 301 and 302, same-same in everyone's book. It's simply splitting a nano hair.
If you STARTED with a 283, and bored it .120, you have (or had back then) a 301-------HOME BUILT BY HOTRODDERS!
If you START with a 327 (true 4in bore) today, and put a 283 crank (3.0in stroke) in it, then you have a 302---------------BUILT BY CHEVROLET AT THE FACTORY.
So, for us old timers like me, when someone speaks of a 301, we automatically know that is a BORED 283 block. If you speak of a 302, we automatically know you are referring to a block that had a 4in bore to begin with.
Is it peecan or pecon, tomatoe or tomahtoe, potato or potahto? :confused:

My recollection was also that the 301 CID homebuilt started with a .125" bore also. That said I sure ain't gonna argue over .005"

Tom ,it wasn't intended to bust your chops but I recall ordering .125 over pistons back in 65 for an M/P car.

And quite honestly, the overbore may have been .125, but the piston was listed as a .120oversize for a 283.
Today, I believe the .120 over piston for a 283 and a Std bore 302 piston are listed as the SAME piston.
Remember, prior to the introduction of the mid-67 302 Z/28 engine, there was no such thing as a "302" piston. Actually, there was no such thing as a "301" piston either. It was a Piston, Chevrolet, 283 cubic inch, .120 oversize.
And they were NOT available from GM, they were only available from aftermarket sources such as Thompson (and this was Pre-TRW!). Anyone remember Thompson pistons? Jahns? Venolia?
Sorry, that's the wrong question. The question SHOULD be, "do we have anyone old enough here who can remember that far back"?

thank you for the great replies very informative:beers:

Tom ,it wasn't intended to bust your chops but I recall ordering .125 over pistons back in 65 for an M/P car.

I know that! :D
AND, ALSO, it is quite possible that .120 and .125 over could have simply been the difference between piston manufacturers.

And quite honestly, the overbore may have been .125, but the piston was listed as a .120oversize for a 283.
Today, I believe the .120 over piston for a 283 and a Std bore 302 piston are listed as the SAME piston.
Remember, prior to the introduction of the mid-67 302 Z/28 engine, there was no such thing as a "302" piston. Actually, there was no such thing as a "301" piston either. It was a Piston, Chevrolet, 283 cubic inch, .120 oversize.
And they were NOT available from GM, they were only available from aftermarket sources such as Thompson (and this was Pre-TRW!). Anyone remember Thompson pistons? Jahns? Venolia?
Sorry, that's the wrong question. The question SHOULD be, "do we have anyone old enough here who can remember that far back"?

You remember Duffy's ? Old Forged True?
Racerbrown cams?

I used to work at a automotive machine shop and then a speed shop-we slid a lot of those Duntov cams in small blocks. Seemed like they would rev forever.

Amazing combo
67 Camaro 327 2v Saginaw 4 speed 3.31 gears
Add double hump 461 heads, 4v and intake, and 097 solid Duntov cam and headers.

Another....

301 with 461X heads, Torker II intake, 500 CFM Eddy, I don't recall the cam but is was from Melling, 3.08 one wheel wonder in the rear, all packaged in a '64 2 door Nova post. This was a trip to behold... GREAT fun to drive.

Mike