deputybob

I need some help. Im wanting to build a 1969 Z 28 engine,and i cant find specs to build it. I know I'll need parts but where can I get the specs as to what was in the engine ,parts wise .what specific block,cam,crank etc.etc.
did they have solid lifters or hyd. what heads.
Any help would be great.
Im on the Chevelle net, and the guys over there told me that some of you guys would be glad to help.
Thanks in advance for the help,
Bob
Chevy all the way!!!!

spinout

check on nastyZ28.com all the numbers are there

jg95z28

http://www.camaros.org should have what you're looking for.

stale

Ooooh, finding the correct block casting is going to be tough from what I hear. Good luck. That 302 is legendary for power

TJS69

A 302 huh. You have to really wind a 302 to make power. We're talkin' 7000 RPM's here ! A '69 block would be a "DZ" block. the block is nothing special with a 4" bore. (same as a 327 or a 350). The crankshaft has the same stroke as a 283. (3" stroke) In '67 and 68' you could use a 283 crankshaft as the blocks were small journal then. In '69 the 302 went to a large journal crankshaft. The heads were of the "186" variety in '69. 2.02 intake valves and 1.6 exhaust valves. These were Camel hump or double hump as they were called. The cam was a solid lifter unit and I believe was the 30-30 cam. It had an aluminum high rise intake manifold and a 780 CFM holley carb.
This motor could not be used with an automatic trans. The motor was a real dog at low RPM's. I would not think about building one now. It was a terrible motor on the street. Build a 383 that will out perform most engines ! To build an original motor would be expensive. As far as camshafts are concerned, the last 35 years have brought many improvements !

LameRandomName

That's not exactly true. You do need a looser converter though.



As far as reproducing a 302, that's just a 327 with a 283 crank. But unless you have an actual DZ block, it's not going to be "correct" anyway.


You'd be far better off building a larger cubic inch engine and disguising it.


A simple can of orange paint will hide aluminum heads, and you can top it off with an Offenhauser cross ram of the same style that was used on real Z28's.

PAW sells the Offenhauser Cross-Ram setup.

Base................... OFF-5893 ..... $278.95
Dual Quad Top...... OFF-5903 ..... $132.95
Linkage Kit .......... OFF-5802 ..... $69.95

The other factors were that the DZ302 used a relatively large cam, so to get the right sound you would need a cam of the appropriate size for then engine you chose; and you'll need to use a chambered exhaust. Not glasspacks, chambered. Either that or unmuffled pipes, and either way you need a rear exit set-up that comes out past the bumper.

TJS69

The 302 engine never came from the factory with an automatic transmission. Can you do it ? Maybe. The crossram intake was a dealer installed option and the car never came from the factory with one installed. The compression ratio was about 12.5:1. 64cc heads and domed pistons. The easiest way to try to make a replica, would be to bore a 283 out.

jg95z28

FWIW In 1969 Chevrolet got approval to use an automatic in SCCA Trans Am racing. (The Z/28 was created especially for the Trans Am series.) Camaro Untold Secrets 1967-1969 discusses it with some detail. Others are correct, a 1st gen Z/28 never came from the factory with anything but a 4-speed. However there was some testing and perhaps even a few Trans Am cars that ran automatics.

markinkc69z

Why do you want to build one? Seriously ask yourself that question. I wanted to build one too, and did. I love rpm and got my wish. I started the project wanting a performance 302 build like I envisioned somebody like me would have done back in the early 70's. My machinist warned me that 302's were taken out all the time and replaced with LT1 style 350's when Z's were a dime a dozen. I didn't care and had to have one for myself. My buildup follows:

4" bore large journal block
DZ 3" crank
Windage tray
Melling M55A Z/28 pump - 60psi but low idle pressure
Powdered metal 5.94" rods with ARP bolts
Off the shelf SRP domed pistons for a 350
Second gen off road 302 solid camshaft
Victor 7700 heads - first huge mistake
2" HTC coated Headman headers - second big mistake
Offenhauser cross ram, and purchased 3 tops - 2x4 , 1x4 and 1x4500

Holley 0-4295 carbs - 2x585 cfm - can't buy these anymore from Holley, some jackass is trying to bring back crossram parts and make them GM certified at reduculously inflated prices. Holley only makes the carbs for him now. The linkage doesn't fit the Offy intake without a spacer- the top is not a perfect copy of the GM manifold.
Aluminum flywheel - another no no

CenterforceII pressure plate for a hemi base pressure close to a dual friction gm setup
Hays super connector 11" disc
BW Super T10 with aftermarket cast iron case

I did my research on the cross ram equipped 302 and though my header choice seems flagrantly wrong, it mirrored Chevy's testing in the 60's. They just didn't have the lazy high flowing heads I used.
Engine idled @ 1300 rpm with an undescribeable rowdiness. At 1250 rpm it would shut off
With my 924-16 springs 8000 rpm was a reality, right now.

Performance was less than that of my old LT1 combination with a 1st design off-road 302 cam. That old motor would run low 12 teens all day long through the mufflers on street tires.

The cross ram has some serious mixture distribution issues requiring a fatter than optimum tuneup. Maybe I'll try another day.

I have made several changes to this engine to improve the performance. Replaced the heads with some iron eagles that are 2.02 200 cc instead of 2.08 215 cc to improve velocity. Replaced the flat tappet with 3 rollers now looking for "the one". Put a strip dominator on it that works very well with my old claw carb. Just purchased aintake and 4-bbl throttle body for an efi conversion, should be complete in the next 30 days. Replaced 2" headers with my old 1 7/8" set for more velocity and mid-range.

All in all I would recommend against it for several reasons. The silliest reason is the looks I get back when someone asks what I got in my Camaro and tell them "302". They look at me as if I'm blue and stupid. I even put a set of reproduction never released "CAN AM 302" stickers on the fenders to try to back me up....haha.

Yes it will happlily do rpm like nobody's business and it sounds great. It will rpm higher than what a synchronized transmission is happy shifting at and I would strongly recommend a Liberty "crash box" pro shift conversion for anyone wanting to go there.

Dragstrip performance is dismal in an all steel car with light flywheel ect... 4000 rpm and it shuts off with slicks. 6000 rpm and the clutch doesn't have the properties to hold it and the engine drives right through. MPH is there but its all about the first 330'.

If you still want to do it I've got some parts....

markinkc69z

Cam specs for the 302:

Factory 254/254 .485/.485 114 deg lobe sep

1st design off road "140" cam 257/269 .493/.512 112 lobe sep

2nd design off road "724" cam 262/273 .488/.509 112 lobe sep

Duration is @ .050, all cams are solid lifter.

FiefSS

I love my 302.. but its got sooo many problems and we are just starting out lol.. but I wouldn't have it any other way. Rebuilding my dads teenage car is too much fun!

btw it had an automatic behind it in a Bel Air at once point in its life.. dad says he drove it, and doesnt say it was unhappy.. so I guess you can run a 302 with an auto if you wish... Just don't try for a/c and all should be good.

markinkc69z

Well its all in the cam because Bel Aire's had 283s in the 60's with powerglides! In all reality a Bel Aire is probably only a few pounds heavier than a Camaro. I remember roll starting my buddies Bel Aire down the hill just because we could with the old cast iron powerglide...

FiefSS

So.. you are gonna do fuel injection on that lil 302?? Got some info on that, cause I think that might be something cool to do. Dad never said he got the motor to fully be happy with any carb/ intake thats ever been on there.. its running a 450cfm atm.. Its always idle'd fine, warmed up it will idle at 900rpm.. little iffy when cold but right at 1100ish.. I'm no expert when it comes to carbs or fuel injection, but it is one possible route once the car around the motor is done to shoot for.

markinkc69z

Yes, I purchased and built a MegaSquirt ecu for it. I also picked up an Edelbrock manifold and fuel rails. I am using a BBK 4bbl throttle body and I have some bosch low-z 37# injectors. I really can't wait to get it together. I just have a small wiring harness to build and I'm all set.

FiefSS

Ok sounds awesome, keep me informed and possibly others.. lol i dunno if anyone else is interested.. Hottroders blasted me the one time over there when i asked for a 302 question.. i dunno but 302 rolls off the tongue better than 454 to me hehe..