big_truxx
1/2 ton status
I know the old 302 SBC was a 4" bore with a 3" stroke. It was built with a 350 block wasn't it? Also where could I find a 3" stroke crank?
CK5
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302 SBC questions
- Thread starter big_truxx
- Start date
maybe....
The 302 they had in the 69 Z28 camaro's was a hybrid the made by using a 283 style 3 inch stroke crank in a 327 block(4 inch bore)..I dont recall all the specs,like if they were 4 bolt main motors or not--I know a few guys who "made" a 302 by putting a 307 crank in a 350 block(that makes the same stroke and bore as a302 had)--this way they could use a 4 bolt main block,but the crank was still a cast one though--you could put a 283 crank in a pre-67 327 block,but not the later 327's or 350's due to the smaller main bearing journals on the older motors.(I think the 302 had a unique crank all its own,with large journals and the short stroke)...the 302 was mainly a high RPM screamer with a hot cam and lots of top end power,but they were doggy until you wound them up,not much low end torque ..not a good truck or 4x4 motor,in my opinion...
The 302 they had in the 69 Z28 camaro's was a hybrid the made by using a 283 style 3 inch stroke crank in a 327 block(4 inch bore)..I dont recall all the specs,like if they were 4 bolt main motors or not--I know a few guys who "made" a 302 by putting a 307 crank in a 350 block(that makes the same stroke and bore as a302 had)--this way they could use a 4 bolt main block,but the crank was still a cast one though--you could put a 283 crank in a pre-67 327 block,but not the later 327's or 350's due to the smaller main bearing journals on the older motors.(I think the 302 had a unique crank all its own,with large journals and the short stroke)...the 302 was mainly a high RPM screamer with a hot cam and lots of top end power,but they were doggy until you wound them up,not much low end torque ..not a good truck or 4x4 motor,in my opinion...
84_Chevy_K10
Banned
327 and 350 = same block if both are large journal.
A modern 1 piece rear main seal 302 could be built with a 350 block and a crank from a 262 V8.
IMO, this stuff is outdated. 383s spin 6,500 RPM all day long. 350s 8000 plus. With modern balancing techniques, good connecting rods, bolts, and forged gear, short stroke motors are a thing of the past unless to try to get into a racing class by reducing CID. Why run 302 CID and spin it 8,000 RPM, when you can run 383 CID and spin it 6,500 or so and it'll make WAY more power?
The original 302 Chevy, called a "301" by hot rodders of the day, was a 283 block bored to 4".
A modern 1 piece rear main seal 302 could be built with a 350 block and a crank from a 262 V8.
IMO, this stuff is outdated. 383s spin 6,500 RPM all day long. 350s 8000 plus. With modern balancing techniques, good connecting rods, bolts, and forged gear, short stroke motors are a thing of the past unless to try to get into a racing class by reducing CID. Why run 302 CID and spin it 8,000 RPM, when you can run 383 CID and spin it 6,500 or so and it'll make WAY more power?
The original 302 Chevy, called a "301" by hot rodders of the day, was a 283 block bored to 4".
sled_dog
1 ton status
I want to build an aftermarket 400 block with a 3" stroke. 4.165 bore x 3" stroke = an even higher revving 327 
. Yes I know modern balancing technology allows for better RPMs out of bigger motors but you still have Piston Speed and the less piston speed the high revs. I am pretty certain I will never do it cause I could build something better and more powerful for the same money. If I ever have a race shop maybe I will do it just to be different. The original 302s ate up the road racing circuit but didn't have a chance in the 1/4 mile.
. Yes I know modern balancing technology allows for better RPMs out of bigger motors but you still have Piston Speed and the less piston speed the high revs. I am pretty certain I will never do it cause I could build something better and more powerful for the same money. If I ever have a race shop maybe I will do it just to be different. The original 302s ate up the road racing circuit but didn't have a chance in the 1/4 mile.R72K5
Banned
350 327 and 302 are shared blocks, especially in 69
big_truxx
1/2 ton status
the 307 has a 3.250" stroke. That added to the 350 block would be the 327 I found a cool info page; http://www.nastyz28.com/sbcmenu.htmlhas info on SBC engines. I would assume that the 302 used the standard 5.7" SBC con rod right?
I found a cool info page; http://www.nastyz28.com/sbcmenu.htmlhas info on SBC engines. I would assume that the 302 used the standard 5.7" SBC con rod right?
big83chevy4x4
3/4 ton status
the 302 was never made in 69, they stopped in 68 when they lifted the CID rule.
the 302 was a road racing engine made to fit the rules at the time. 327 was too big and the 283 did not have enough power to make the racers happy, so they put a 283 crank in a 327 block and thus creating the 302. rated from the factory at 295 hp but were closer to 395 hp.
the 302 was a road racing engine made to fit the rules at the time. 327 was too big and the 283 did not have enough power to make the racers happy, so they put a 283 crank in a 327 block and thus creating the 302. rated from the factory at 295 hp but were closer to 395 hp.
R72K5
Banned
big_truxx
1/2 ton status
I really don't know about high revving a longer stroked motor. I just feel that a short stroke is always better revved. 
maybe just a matter of opinion. I'm just curious about 302's as they were less common than the other motors and not around anymore. Does anyone make a 3" stroke crank these days?
maybe just a matter of opinion. I'm just curious about 302's as they were less common than the other motors and not around anymore. Does anyone make a 3" stroke crank these days?
big83chevy4x4
3/4 ton status
i have never seen one in a 69 only 67 and 68. but i wasn't around then, so what do i know. its just was i have been told and read
big_truxx said:
Scat has any stroke you can think of.... not sure about the others...
NJBLZ
1/2 ton status
I like the 377. 400 bore- 4.126" x 350 stroke 3.48"
I plan on having one built for my nova, with a dart little m block
I plan on having one built for my nova, with a dart little m block
big_truxx
1/2 ton status
84_Chevy_K10 said:
I ran some #'s on the dyno and @ 6500rpm the 383 is past peak hp and has lost 80hp from its peak #. It peaked at 5,000. I don't know about a 350 @ 8,000... I guess maybe in a $10,000 crate it may still be making good power at that speed but for a home built on a budget type "normal" motor I do not see anything spinning 8 grand. I guess another thing I was thinking about is; doesn't rpm affect your speed anyway? Like wouldn't an engine that has 350 peak hp at 6,500 go faster than on that has 350 peak hp at 5,000?
big_truxx
1/2 ton status
NJBLZ said:
That's actually a 372 CID.
377 comes from 4" 350 and 3.750" stroke crank 
Yup!--I was wrong!!
Yes,you are correct,it WAS a 283 crank in a 327 or 350 block that makes a 302--I was thinking of my friends "mongrel" motor he made out of spare parts,he used a 307 crank in a 350 block to make a 4 bolt main 327 cid motor--I guess my brain cant remember everything back that far,when I had hair,teeth,and better eyesight!
But I'm 99% sure they had 302's in 69,my friends Z28 had one factory,he bought it brand new,still has it,only 34,000 miles on it now--its a convertible too!--he had it appraised,the guy said its worth 25.000 bucks minimum!
--now he's scared to take it out of the garage!
Yes,you are correct,it WAS a 283 crank in a 327 or 350 block that makes a 302--I was thinking of my friends "mongrel" motor he made out of spare parts,he used a 307 crank in a 350 block to make a 4 bolt main 327 cid motor--I guess my brain cant remember everything back that far,when I had hair,teeth,and better eyesight!
But I'm 99% sure they had 302's in 69,my friends Z28 had one factory,he bought it brand new,still has it,only 34,000 miles on it now--its a convertible too!--he had it appraised,the guy said its worth 25.000 bucks minimum!
--now he's scared to take it out of the garage!big_truxx
1/2 ton status
diesel4me said:Yes,you are correct,it WAS a 283 crank in a 327 or 350 block that makes a 302--I was thinking of my friends "mongrel" motor he made out of spare parts,he used a 307 crank in a 350 block to make a 4 bolt main 327 cid motor--I guess my brain cant remember everything back that far,when I had hair,teeth,and better eyesight!
But I'm 99% sure they had 302's in 69,my friends Z28 had one factory,he bought it brand new,still has it,only 34,000 miles on it now--its a convertible too!--he had it appraised,the guy said its worth 25.000 bucks minimum!
They did have 302's in 69. Also how did they put the 283/265 3" stroke small journal in the large journal block? weld and machine the crank or what?
'69 Z28's had a 302 in 'em
BTW, a short stroke allows a lower average piston speed at a given RPM. The realized limit of the rods/pistons/cranks is this "average piston speed". A longer stroke causes a higher average piston speed at a given RPM.
You really need to "TUNE" your entire vehicle to determine what is the best combination. For example, you should consider weight, rearend ratio, transmission gearing, tire size and finally engine RPM band and to some extent aerodynamics(of the vehicle) that you plan to run in given driving conditions.
when you figure all that out, you should know what kind of RPMs you need to run...... and then you can choose the right characteristics of the engine (like intake and exhaust flow, cam, compression, stroke, bore, etc..) for an amount of power you want.
.... if you can't figure all that out... then remember the golden rule..... there's no (or few) replacements for displacement.
BTW, a short stroke allows a lower average piston speed at a given RPM. The realized limit of the rods/pistons/cranks is this "average piston speed". A longer stroke causes a higher average piston speed at a given RPM.
You really need to "TUNE" your entire vehicle to determine what is the best combination. For example, you should consider weight, rearend ratio, transmission gearing, tire size and finally engine RPM band and to some extent aerodynamics(of the vehicle) that you plan to run in given driving conditions.
when you figure all that out, you should know what kind of RPMs you need to run...... and then you can choose the right characteristics of the engine (like intake and exhaust flow, cam, compression, stroke, bore, etc..) for an amount of power you want.
.... if you can't figure all that out... then remember the golden rule..... there's no (or few) replacements for displacement.
pauly383
Daddy383
big_truxx said:
They used a large journal crank in 68 and 69 casting # 3279 , forged steel
big_truxx
1/2 ton status
chevy_muscle said:
pauly383
Daddy383
While displacement is great , every 100 pounds is worth a tenth of a second
