Stock and hopped Z-28 engines here..

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

Post by F-BIRD'88 »

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
GM did do a 400.. You went to your Pontiac, Olds or Buick dealer to buy a high performance 400.

The 302 Z/28 should have come with the 327/350 HP
"151" cam if ordered with 3.73:1 axle.
It would have been better and faster in stock form in every way that matters. I know of Z/28 owners that did just this change back in the day.. The car was better in every way that matters.
On the 30-30 solid cam progressivily loosening the valve lash and advancing the cam improved performance on the street . 114LSA 110/118 advanced to 107/121 centers. As you loosen the lash the valvetrain gets noiser but the net at the valve duration and overlap get reduced to good effect for the street with milder 3.73 oem gearing on the Z/28. Even when headers are added
, indicating that a shorter duration street solid lifter cam would have been better on the street. where 4.56-4.88-5.13 gears are not desired by most.
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Re: Stock and hopped Z-28 engines here..

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Further, this is where the aftermarket cam grinders can and did come in to good effect.

EG: swapping out the oem gm 30-30 camshaft for a Ultradyne- UDHarold (Lunati) "Street-strip" series lil solid lifter cam #401A2LUN will make the 302 Z/28 do everything that matters, better.
272/272 238/238 @.050" .485" .020" 110LSA 104/116 centers.. On this lil UDHarold street brat solid lifter cam you can dial in the lash setting from .016" to.028" and play with the cam installed position phasing to adjust and fine tune the 302 engine power curve. Wether with stock exhaust manifolds or with headers.
Its going to be a much better "street engine".
Now your 67-69 302 Z/28 will need those traction bars and a driveshaft loop..

Isky had and has today similar cams Z20, Z25, Z27, Z30, Z50 grinds etc in their catalog this also serve this purpose for a Street 302 Z/28. A custom grind was and still is just a phone call away if what you find in the catalog is not quite right for you.
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Re: Stock and hopped Z-28 engines here..

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In todays market there is little reason to even consider 302 cu in displacement. Those old double hump heads are nothing to consider for making horsepower. Thats why they had to rev them so high and gears. Cubic inches is what makes torque/horsepower. 350 cu in is the bottom line to consider these days. 302 z/28 only came about for one reason, Trans Am rules which had to be on showroom floors. If it wasn't for that it wouldn't have happened.
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Re: Stock and hopped Z-28 engines here..

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rgalajda wrote: Sat May 07, 2022 3:34 pm In todays market there is little reason to even consider 302 cu in displacement. Those old double hump heads are nothing to consider for making horsepower. Thats why they had to rev them so high and gears. Cubic inches is what makes torque/horsepower. 350 cu in is the bottom line to consider these days. 302 z/28 only came about for one reason, Trans Am rules which had to be on showroom floors. If it wasn't for that it wouldn't have happened.
For true. Been mentioned several times over the previous posts the only reason for a 302" today is stubborness or the very rare vintage racer.

Recently, a local car collector with too much money reportedly paid $5000 for a well-used DZ block and heads and $6000 for the cross-ram 2x4, spent another $12,000 having it built up for his perfectly restored '69 Z28, which he then had $2,000 of chassis-dyno-tune. The end result was still pretty much the wet dog the Z28 always was and at a club drag day he got his doors blown off by a kid with a $5,000 crate 383" which idled, ran smoothly and got decent fuel mileage with street gears.

Feeling sorry for him, friends told him he should run it in vintage road races, where it fit the class. He said, "Don't want a roll bar to mess up the interior and there's $40,000 of paint and body work; I'm going to get an enclosed trailer to make sure it doesn't pick up any rock chips. Shows only from here on."

The plus side is he has the nicest '69 Z28 possible to build. The bad news is it's useless as a car.
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Re: Stock and hopped Z-28 engines here..

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What fascinates me was when the auction blocks started referring too them as DZs and people started thinking of them as some special Z compared to an ordinary Z28. All 302 Z28's are DZ . DZ refers to the code on the build sheet of all 302 Z28's.

Don't get me wrong , I respect a preserved Z28 in all matters. It's a part of our history/preservation, and that matters.

14 second 1/4 mile from a stock 302 was impressive. I watched GTO's in pure stock run 14's et with 400 cu in and 455 cu in .

The first time I took my 1970 z28 to the drags the first run was a low 14s almost breaking into 13s ( it already had headers on it )

I would not refer to those 302s as slouches/wet dogs or whatever. Every thing has to be put in respective.
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Re: Stock and hopped Z-28 engines here..

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I started going to the drags here in Southern Ontario Canada before I had my drivers license (to watch) in 1969.
There was no sticky on the track in those days.

St Thomas Dragway , the oldest running track in Canada , and it still runs. We also have Grand Bend Dragstrip , both are within 30 minutes of my home.
Pure Stock ( practically showroom ) was a big class in the late 60s, early 70s at St Thomas Dragway.

My brother in law ran a 1969 427 Copo Chevelle pure stock. Mid 13s to low 13s et (13.1) to be exact.
My brother ran a 1970 GTO 455. Mid to low 14s et
My other brother ran a 1971 Boss 351 a couple of times. Low 14s et
!968 Beaumont ( chevelle ) 327/275 horse 2 speed automatic . High 15s et

A friend with a 1969 GTO Judge ran high 13s

I was glad to get my drivers license in 1971. Bought a 1970 z28 soon after.
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Re: Stock and hopped Z-28 engines here..

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rgalajda wrote: Sat May 07, 2022 3:34 pm In todays market there is little reason to even consider 302 cu in displacement. Those old double hump heads are nothing to consider for making horsepower. Thats why they had to rev them so high and gears. Cubic inches is what makes torque/horsepower. 350 cu in is the bottom line to consider these days. 302 z/28 only came about for one reason, Trans Am rules which had to be on showroom floors. If it wasn't for that it wouldn't have happened.
92-97 y body 4 bolt lt1 block, crank out of a Buick baby lt1. Stock lt4 heads and intake ported. Probably easier ways to get good power out of a sbc, but it would be interesting to see a max effort 302 built with these OEM pieces and modern efi. Something that really could rev and run cleanly from 2000-7000 rpm and probably surpass the original for emissions compliance and overall power with a hydraulic roller cam. I Have a feeling even the most hard core purists would accept it in a tastefully done restomod. Put a t56 in the car, modern brakes , coilovers etc. But keep the engine at stock displacement and build it with as many OEM lt1 parts as possible.
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Re: Stock and hopped Z-28 engines here..

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Bill Chase wrote: Sun May 08, 2022 11:29 amkeep the engine at stock displacement and build it with as many OEM lt1 parts as possible.
One more time, the question is why built it at 302"? It will cost more and be slower than the larger displacement builds. No one looking at the outside can be impressed by what they can't see.
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Re: Stock and hopped Z-28 engines here..

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PackardV8 wrote: Sun May 08, 2022 5:40 pm
Bill Chase wrote: Sun May 08, 2022 11:29 amkeep the engine at stock displacement and build it with as many OEM lt1 parts as possible.
One more time, the question is why built it at 302"? It will cost more and be slower than the larger displacement builds. No one looking at the outside can be impressed by what they can't see.
Well, as a throwback mix 90's technology and arguably the best factory engineered sbc and integrate it into the original Z28 cars classic looks of the first gen fbody, with the last of the gen1 architecture. I realize the lt1 we're officially the gen2 and had substantial differences, but outwardly still resembles the gen1. A dz302 restomod built circa 1992-1997 was the idea. In this day and age many would argue why use a sbc at all, why not just do an ls engine. Pay homage to the original, satisfying the purists by keeping it at 302 c.i. so what if it's underpowered in comparison. The original dz302 was underpowered, done only to meet class rules. And no offense intended, but why build Studebaker or Packards when so many other engines can be built cheaper and make more power, with reliability and efficiency? Surely a man in your position can appreciate the nostalgic aspect of keeping key parts true to the original build?
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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
First off what is a 301 he is referring to?

Bill: Have you had experience building a 92-97 y body 4 bolt lt1 block,
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Re: Stock and hopped Z-28 engines here..

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rgalajda wrote: Mon May 09, 2022 6:58 am
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
First off what is a 301 he is referring to?

Bill: Have you had experience building a 92-97 y body 4 bolt lt1 block,
327 with a 283 crank, they used to be called 301's because the Hot Rodders didn't round up the 301.59 ci displacement.
When the factory did it, they did of course round up.

283's and 302's were appropriate capacity for the little heads of the day. The tight chambers they needed for compression shrouded the valves badly.
Ignorance leads to confidence more often than knowledge does.
Nah, I'm not leaving myself out of the ignorant brigade....at times.
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Re: Stock and hopped Z-28 engines here..

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Bill Chase wrote: Mon May 09, 2022 5:23 am
PackardV8 wrote: Sun May 08, 2022 5:40 pm
Bill Chase wrote: Sun May 08, 2022 11:29 amkeep the engine at stock displacement and build it with as many OEM lt1 parts as possible.
One more time, the question is why built it at 302"? It will cost more and be slower than the larger displacement builds. No one looking at the outside can be impressed by what they can't see.
Well, as a throwback mix 90's technology and arguably the best factory engineered sbc and integrate it into the original Z28 cars classic looks of the first gen fbody, with the last of the gen1 architecture. I realize the lt1 we're officially the gen2 and had substantial differences, but outwardly still resembles the gen1. A dz302 restomod built circa 1992-1997 was the idea. In this day and age many would argue why use a sbc at all, why not just do an ls engine. Pay homage to the original, satisfying the purists by keeping it at 302 c.i. so what if it's underpowered in comparison. The original dz302 was underpowered, done only to meet class rules. And no offense intended, but why build Studebaker or Packards when so many other engines can be built cheaper and make more power, with reliability and efficiency? Surely a man in your position can appreciate the nostalgic aspect of keeping key parts true to the original build?
Some people, including me,like the challange of getting more power of an old turd.You can't just order parts from Summit...you need to be innovative...
Motorcycle land speed racing... wearing animal hides and clinging to vibrating oily machines propelled by fire
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Re: Stock and hopped Z-28 engines here..

Post by PackardV8 »

Tom68 wrote: Mon May 09, 2022 7:22 am
rgalajda wrote: Mon May 09, 2022 6:58 am
pdq67 wrote: Sat Oct 10, 2020 10:33 amI made a junk 301 that I figure was only like only 325 hp..So know a little bit about them. pdq67
First off what is a 301 he is referring to?
327 with a 283 crank, they used to be called 301's because the Hot Rodders didn't round up the 301.59 ci displacement.
When the factory did it, they did of course round up.

283's and 302's were appropriate capacity for the little heads of the day. The tight chambers they needed for compression shrouded the valves badly.
The first 301"s were 283"s bored .125" over. Some made more power; some just overheated, especially when equipped with 13:1 Jahns popups. R.I.P., pdq67
Some people, including me,like the challange of getting more power of an old turd.You can't just order parts from Summit...you need to be innovative...
A northwest vintage racer was always blowing up his 302"s and asked how to make one reliable. Answer, build a less expensive 383", stamp the block DZ and just turn it hard enough to keep up with the pack; it was still running last I heard.

Another guy, with a Parnelli Jones clone Mustang found the expense of legal Boss 302"s was making his wife cranky about his racing. He bought a obsolescent NASCAR takeout, doesn't raise the hood, and now has a lot more fun racing. To his credit, he lets the guys with legal engines win if they can hold together.
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Re: Stock and hopped Z-28 engines here..

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rgalajda wrote: Mon May 09, 2022 6:58 am Bill: Have you had experience building a 92-97 y body 4 bolt lt1 block,
I owned a 93 trans am,as well as a 97 trans am,both were stock bolt on cars. I realize that most of the f bodies got 2bolt mains and a softer tune. But I am familiar with the platform a little bit. I get what you guys are saying just do a 350/383. Just always thought it would be cool to do the short stroke baby lt1 crank in the 4 inch bore block and wind it up using as many oem parts as possible. For the same reasons many of you gents tinker with older engine platforms. There's just something about the sound of a short stroke small block at 6500+ rpm. I mean, at the end of the day does any single facet of a performance automobile fall into the category of practical, sensible use of hard earned dollars? We do it because we love it. And personally I think a destroyed lt1 retrofit Into a first gen fbody with as many OEM parts as possible would be really neat! 🤣
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Re: Stock and hopped Z-28 engines here..

Post by Bill Chase »

Truckedup wrote: Mon May 09, 2022 7:56 am
Bill Chase wrote: Mon May 09, 2022 5:23 am
PackardV8 wrote: Sun May 08, 2022 5:40 pm One more time, the question is why built it at 302"? It will cost more and be slower than the larger displacement builds. No one looking at the outside can be impressed by what they can't see.
Well, as a throwback mix 90's technology and arguably the best factory engineered sbc and integrate it into the original Z28 cars classic looks of the first gen fbody, with the last of the gen1 architecture. I realize the lt1 we're officially the gen2 and had substantial differences, but outwardly still resembles the gen1. A dz302 restomod built circa 1992-1997 was the idea. In this day and age many would argue why use a sbc at all, why not just do an ls engine. Pay homage to the original, satisfying the purists by keeping it at 302 c.i. so what if it's underpowered in comparison. The original dz302 was underpowered, done only to meet class rules. And no offense intended, but why build Studebaker or Packards when so many other engines can be built cheaper and make more power, with reliability and efficiency? Surely a man in your position can appreciate the nostalgic aspect of keeping key parts true to the original build?
Some people, including me,like the challange of getting more power of an old turd.You can't just order parts from Summit...you need to be innovative...
That's my entire point and reasoning for doing a short stroke 4" bore lt1 with as many OEM parts as possible. It would be unique.
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