I'm looking at a Z with a 302... I've never driven a Z yet. obviously Chevy knew what they were doing, but why did they use a 302? You hear so much good stuff about the Chevy small block 350. I'm sure Chevy knew what they were doing... just curious.
why did they put a 302 in the Z?
okiemark
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I'm looking at a Z with a 302... I've never driven a Z yet. obviously Chevy knew what they were doing, but why did they use a 302? You hear so much good stuff about the Chevy small block 350. I'm sure Chevy knew what they were doing... just curious.
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It was utilized for use in SCCA racing, which had a limitation on cid.
The Z/28 grew in popularity on the street, so the production #s went up each year from 67-9.
The Z/28 grew in popularity on the street, so the production #s went up each year from 67-9.
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Read here:
http://www.67z28.com/history.htm
Basically to get the Cubic inches under the SCCA rule or limit of 305 CI.
http://www.67z28.com/history.htm
Basically to get the Cubic inches under the SCCA rule or limit of 305 CI.
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The gentlemen that have responded are absolutely correct regarding why Chevy went with the 302. What you might not realize is that the 302 will absolutely smoke a 350...in this case, size doesn't matter! :thumbsup:
Well you are correct that the 302 will outperform a stock 350 chev of the same year... chevy did pull a few tricks to get that done like under rating/advertising the hp that the 302 (also solid lifters and basically a not very street friendly cam)puts out also these engines were primarily backed by a 355 or 410 gears I believe where as most of the 350's were backed by a much more highway friendly diff. Not to mention the transmission oops i just did lol. 
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And that horse power rating was a turn-off for some of us kids. 290HP?? Nope, give me muscle! L78 for me! Well, actually, I bought my L88 stuff a year before I ordered my car. I planned to swap but my buddies said that the L78 would be so strong that I wouldn't bother. They were right, but then it broke. For some reason I haven't been able to break my L88??????
Stock to stock maybe. My built 350 will run with any 302 easy.
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They also wanted to make sure that as many ford engineers would loose they jobs as possible.
Actually, only sort of. If you compare them as delivered from the factory, usually, but not always. Now if you give the 350 the same compression, cam, heads, intake, and big ol'honking Holley that the 302 came with, nope, the little 302 won't stand a chance. Now if you ordered a SS350 with the top rated 350, with a 4 speed, cold air induction, and a 4.11 rear end, I bet it would give the stock street version of hte 302 a run for it's money.
I have to respectfully disagree. I've had the 69 Z/28 engine, the 302, and the 1970 Z/28 engine, the LT1 350, in the same car. In stock form the 70 LT1 350 moves the car quicker on the street and at the strip. Putting aside minor details, they are essentially the same engine except the 350 has a longer stroke. While the 302 will wind a bit tighter, the extra torque and dispacement of the 350 makes more hp and puts up lower numbers.
BTW, I even tried a hybrid of the two: I rounded up a big journal 327 crank and the correct 11:1 pistons. Put those in and made basically a 327 cubic inch DZ motor, and ran that a while. That's was a nice combo.
A 327 like a DZ engine is just the 365hp/327 'Vette engine!
Chevy made the 302.
Ford had a 302 already but they fudged and created both the Boss 302 w/ BIG VALVE 351 Cleveland motor heads on it as well as a tunnel-port if I remember right?,
Pontiac created a short decked "303" and AMC had their 304.
I don't think Buick and Olds got in the fray??
And I dearly loved my old junk301 up around 7 to 7,500 rpm grabbing a gear!
It was a real HOOT to me!
pdq67
PS., I think that it is documented back then that TRACO got about 440hp outta their prepped 302's!
Chevy made the 302.
Ford had a 302 already but they fudged and created both the Boss 302 w/ BIG VALVE 351 Cleveland motor heads on it as well as a tunnel-port if I remember right?,
Pontiac created a short decked "303" and AMC had their 304.
I don't think Buick and Olds got in the fray??
And I dearly loved my old junk301 up around 7 to 7,500 rpm grabbing a gear!
It was a real HOOT to me!
pdq67
PS., I think that it is documented back then that TRACO got about 440hp outta their prepped 302's!
My Dad was Pontiac in the 60's. Lucky for ME the CDN Ponchos had Chevy Drive train. I talked him into getting the 330Hp 327 when he ordered his 4 Dr Sedan 68 Strato Chief. He also ordered the TH400 and 12 Bolt 3.08 Posi. Needless to say I had a very big smile when I drove that car. It was a True Warrior and Sleeper.
I still have that Engine - Slightly Modified with a .030" 4 bolt 010 Block, original Forged Crank, Forged Rods, 11.1 TRWs, Edelbrock Rpm and Holley 750DP, Manley 2.02 / 1.6's and Shaft Mounted Rockers. Sigerson Mechanical Flat Tappet. I figure approx 425Hp. I'm really thinking of putting it my 70Z and selling the BBC.
I still have that Engine - Slightly Modified with a .030" 4 bolt 010 Block, original Forged Crank, Forged Rods, 11.1 TRWs, Edelbrock Rpm and Holley 750DP, Manley 2.02 / 1.6's and Shaft Mounted Rockers. Sigerson Mechanical Flat Tappet. I figure approx 425Hp. I'm really thinking of putting it my 70Z and selling the BBC.
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Not to nit pick, but the cam is very street friendly for me with the stock 3.73's that most of the z's had. It was the standard rear end ratio.basically a not very street friendly cam) also these engines were primarily backed by a 355 or 410 gears
Good answers here and GM made the 302 CID for SCCA racing as suggested by RamAIR Dave. But,
The 350 CID will pull from the line (et) better than a 302 simply because of torque generated from the longer stroke engine. However, the 302 will make more horsepower simply because it can, the higher the rpm, the more power strokes and less friction. The 302 is designed to be a high rpm engine, 6000 rpm and above, and can maintain this rpm without a hitch as compared to a 350, all day long. just keep the oil cool and plenty of it.
Just my thoughts. The main reason GM made/sold the 302 was to be competitive in SCCA racing.
The 350 CID will pull from the line (et) better than a 302 simply because of torque generated from the longer stroke engine. However, the 302 will make more horsepower simply because it can, the higher the rpm, the more power strokes and less friction. The 302 is designed to be a high rpm engine, 6000 rpm and above, and can maintain this rpm without a hitch as compared to a 350, all day long. just keep the oil cool and plenty of it.
Just my thoughts. The main reason GM made/sold the 302 was to be competitive in SCCA racing.
That was the setup I had in my 69 after the 3.08's went on the bench. Definitely fun to drive. Made it very hard to get enough rear tire under it.
Wasn't the deal that in order to compete in the Trans Am series, the car had to be "factory available" which meant GM had to have produced so many units for sale to the public in order to qualify? And wasn't there an upper limit of like 305 cubic inches for the class?
alan
alan
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