Stock and hopped Z-28 engines here..

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vortecpro
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Re: Stock and hopped Z-28 engines here..

Post by vortecpro »

canuc wrote: Fri Nov 13, 2020 11:07 pm the 67 in the vid looks like fun https://youtu.be/JR2eawiyK98
out of my pay grade even if it was a 69 . nice hole shot , notice the gutless 302 pull down on the high gear change , 125 mph does that make it close to 500 hp ? nice street ride 🤓
This is a NHRA stocker 465 HP
Racing a NA NHRA stocker should be mandatory before any posting.
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Re: Stock and hopped Z-28 engines here..

Post by cv67 »

Always have a soft spot for them but as said earlier a real basic 400 evn wtih small valve iron heads is so much better.
Soon as I spent some time in a freshly restored crossram Z I lost the desire. not enough torque toe "peel the skin off a grape" as the saying goes. Better have a solid 4.56 gear or lower they are real cool...turds.

If GM woulda done a 400 up like that....beyond legendary
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Re: Stock and hopped Z-28 engines here..

Post by bpenrod »

cv67 wrote: Sun Nov 22, 2020 7:10 pm Always have a soft spot for them but as said earlier a real basic 400 evn wtih small valve iron heads is so much better.
Soon as I spent some time in a freshly restored crossram Z I lost the desire. not enough torque toe "peel the skin off a grape" as the saying goes. Better have a solid 4.56 gear or lower they are real cool...turds.

If GM woulda done a 400 up like that....beyond legendary
But nowhere near as fun!
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Re: Stock and hopped Z-28 engines here..

Post by dfarr67 »

A Couple of months ago I was reading an article about a canted valve version of the 302- I can't believe GM found it was worth soldiering on with, must have cost a mint to not consider.
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Re: Stock and hopped Z-28 engines here..

Post by 408swinger »

SchmidtMotorWorks wrote: Tue Nov 10, 2020 1:19 am 302 Z28s were dogs, I had one with all the supposedly best parts in 1977.
Solid Cam, Smokey intake, 4-speed, 488 gears etc.

My friend with a stock 455 Trans Am automatic beat it with 3 girls in the car and the AC on.
Did that Smokey intake look something like this ?

I ran across this car a few months ago while buying a carb off CL . Its a DZ motor Z28 the guy bought in 72 . I asked if he still had the cross ram and he said no ... he sold the original engine in 74 because wanted more cubes . Bought a 350 with the proceeds...yeah he knows better now 😫
The car has been sitting in that state since late 70s or early 80s
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Re: Stock and hopped Z-28 engines here..

Post by chevyfreak »

408swinger wrote: Sat Dec 12, 2020 12:22 am
Did that Smokey intake look something like this ?
Some of the pics i have of crossflow intakes.

Chevyfreak.
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Re: Stock and hopped Z-28 engines here..

Post by SchmidtMotorWorks »

408swinger wrote: Sat Dec 12, 2020 12:22 am
SchmidtMotorWorks wrote: Tue Nov 10, 2020 1:19 am 302 Z28s were dogs, I had one with all the supposedly best parts in 1977.
Solid Cam, Smokey intake, 4-speed, 488 gears etc.

My friend with a stock 455 Trans Am automatic beat it with 3 girls in the car and the AC on.
Did that Smokey intake look something like this ?

I ran across this car a few months ago while buying a carb off CL . Its a DZ motor Z28 the guy bought in 72 . I asked if he still had the cross ram and he said no ... he sold the original engine in 74 because wanted more cubes . Bought a 350 with the proceeds...yeah he knows better now 😫
The car has been sitting in that state since late 70s or early 80s
Yes.
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Re: Stock and hopped Z-28 engines here..

Post by fdicrasto »

Been off and on watching this post. The "dog" 302 Z-28 in off the dealer showroom floor trim and tune was somewhat gutless, biggest problem was the cam. Once you changed to the "optional Z-28 off road" 140 cam and orange valve springs, good tubing headers, 4:88 rear gear and, the ,at that time, the revolutionary Edelbrock Tarantula intake, it was a high winding ass kicker. There were some sad downtown Rochester street racers who went home crying the blues after the whooping myself and car owner RT Fatty handed them. I have a lot of crazy stories from those days working for Taylor Chevrolet then.
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Re: Stock and hopped Z-28 engines here..

Post by CastIron »

fdicrasto wrote: Sat Dec 12, 2020 7:57 pm Been off and on watching this post. The "dog" 302 Z-28 in off the dealer showroom floor trim and tune was somewhat gutless, biggest problem was the cam. Once you changed to the "optional Z-28 off road" 140 cam and orange valve springs, good tubing headers, 4:88 rear gear and, the ,at that time, the revolutionary Edelbrock Tarantula intake, it was a high winding ass kicker. There were some sad downtown Rochester street racers who went home crying the blues after the whooping myself and car owner RT Fatty handed them. I have a lot of crazy stories from those days working for Taylor Chevrolet then.
My dad bought a '68 Z new when he was service manager for the family Chevy dealership. He says about the same as above. It was a dog off the truck. The intake was a poor casting, he said the ports were closer to triangular than a rectangle, so he cleaned that up and ported the heads. Headers, 140 cam and 5:13 gears made it a missile. His best friend had a 68 396/375 Camaro with 4 speed and 4:88's that got a "warranty replacement" 427/425 short block. The two cars were about even after that. The 396 couldn't touch the 302.

Zeke was totaled so drivetrain went in a 66 Chevy II. Ended up with a roller cam, rev kit and tunnel ram with 660's. Have pictures of it at Rockford (Byron) with the front tires dangling in the early 70's. Engine was supposedly around Dodgeville WI 30 years ago. The guy that bought the Chevy II killed himself in it street racing.

Pic of wrecked Z getting stripped. Dad says it was bent like a banana.
Image

Most of the parts that were still good after the wreck. (He put a 69 cowl induction hood on it shortly before the wreck.)
Image
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Re: Stock and hopped Z-28 engines here..

Post by wwmtlineman »

Back in 1976 our D/S 68 Z/28 ran 116.95 weighing 3125 with driver. This was at the time a blueprinted engine with the required stock Chevy pistons not aftermarket ones, RHS legal heads, {was torn down and legal at a points meet}, Hooker adjustable headers and a Lunati legal stock lift stocker cam. This was just over the national record at the time. We never had it on a dyno but Im curious if anyone would know what that HP would take to run that speed. I figured it on a chart I found online years ago at about 450 Hp to do that. Does anyone know if thats close or not accurate at all ?
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Re: Stock and hopped Z-28 engines here..

Post by PackardV8 »

wwmtlineman wrote: Sat Jan 16, 2021 1:14 pm Back in 1976 our D/S 68 Z/28 ran 116.95 weighing 3125 with driver. . . . I figured it on a chart I found online years ago at about 450 Hp to do that. Does anyone know if thats close or not accurate at all ?
The calculator I use says 390 horsepower.
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Re: Stock and hopped Z-28 engines here..

Post by PackardV8 »

PackardV8 wrote: Sat Jan 16, 2021 2:35 pm
wwmtlineman wrote: Sat Jan 16, 2021 1:14 pm Back in 1976 our D/S 68 Z/28 ran 116.95 weighing 3125 with driver. . . . I figured it on a chart I found online years ago at about 450 Hp to do that. Does anyone know if thats close or not accurate at all ?
The calculator I use says 390 horsepower.
FWIW, these as delivered were 95 MPH runners. The best I ever saw without going into the long block, just tires, gears, bars, headers, dyno tune, was 106 MPH.
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Re: Stock and hopped Z-28 engines here..

Post by wwmtlineman »

Thanks Jack, still not too bad at 100 over the factory rating. Biggest problem at the time was getting enough piston to valve clearance when you couldnt cut the piston valve reliefs per the rules at that time. Ran it as close as .050 which was dangerous. Tighter the valve clearance the faster it ran. Todays rules are so far out there that you cant compare the tow eras. 116.95 was singing it pretty high with 5.57 gears
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Re: Stock and hopped Z-28 engines here..

Post by 54chevkiwi »

Right now facebook marketplace has a dz302 engine, 292 heads ported by brandywine in PA in the 70s and never used, alloy rods, brand new in box tr1y tunnel ram, brand new in box 660s.... all machined and collected in the 70s, new old stock, and been correctly stored for assembly since... he has $7500 on it all
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Re: Stock and hopped Z-28 engines here..

Post by rgalajda »

pdq67 wrote: Sat Oct 10, 2020 10:33 am Just how much power did these little old engines really make?

I made a junk 301 that I figure was only like only 325 hp..So know a little bit about them.

pdq67
No one has mentioned the 1970 350 cu in Z28. I owned one of these when I was 17 years old. Rated at 360 hp in 1970 was more accurate.
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