30/30 Z-28 camshaft replacement? - Team Camaro Tech
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post #1 of 20 (permalink) Old Jul 22nd, 01, 12:54 PM Thread Starter
 
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I have plans for restoring a '69 Z-28 with the DZ302 small block. I have read and heard quite a bit about the lack of bottom end torque from the 302 and the great rush of top end power. Since camshaft technology has greatly advanced in the last 32 years, do anyone have an opinion on a replacement cam which could improve the low end of this motor and not sacrifice the high end? I'm planning on keeping the original 186 heads and the 11:1 compression (looking into piston coatings and other tricks to make it work on 92 octane!).

Thoughts?

Thanks in advance,

ICamaro
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post #2 of 20 (permalink) Old Jul 22nd, 01, 02:40 PM
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I am not sure if the 69 302 is a large journal block or not (never messed with them), but if it is, the easiest, best way in my opinion to gain a LOT of torque at lower speeds would be to swap in a crank from a 350. The short stroke crank and the cam specs are the 2 biggest reasons that 302's have no torque. Plus, the crank job would be totally hidden. That 30-30 cam sounds awesome in a 350! I would consider dropping the compression a bit for either engine...11-1 is possible with pump gas but thats really pushing it...you have to stay on top of the tune at all times, and you'll have little or no saftey margin for stuff like a tank of bad gas.

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post #3 of 20 (permalink) Old Jul 22nd, 01, 03:03 PM
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You must remember that a 30-30 cam was made for a 1964 vette. Thats over 35 years ago there are definately better designs on the market. Try calling the cam companys and see what they recommend.

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post #4 of 20 (permalink) Old Jul 22nd, 01, 03:50 PM
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My friend got Crower to do a custom cam for his 69 Z/28. It has a little more torque, but otherwise you would not know it was not a 30-30 cam.
It has plenty of top end too!
David

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post #5 of 20 (permalink) Old Jul 23rd, 01, 07:16 AM
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I'm running a comp cams 294s in my 327 w/4speed it works well I think it would be a good replacement for the 30/30
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post #6 of 20 (permalink) Old Jul 23rd, 01, 04:23 PM
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The 1970 LT1 cam would be a good solid choice!!

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post #7 of 20 (permalink) Old Jul 23rd, 01, 06:20 PM
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Dennis,
That cam was designed to help the 302 build more low end. But it wound up in the LT1 when the 302 was discontinued.

I bought an LT1 with that cam and drove it for many miles.
I later changed to a mild Crower cam and it had a LOT more low end and better top end too.

The factory cams seem to "come on" at 4500 and up.
The Crower I used came in good at 2500 and just pulled and pulled all the way up to 7000 in my 350. I guess my point is, you can buy a better cam nowadays that will run better on a street engine.
David

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post #8 of 20 (permalink) Old Jul 23rd, 01, 07:34 PM
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The DZ 302 has a large Journal Crank. If you wanna have a fun street car you need at least a 350 crank. You can get alot more Torque that way but it won't be able to wind as high. 95% of your fun is in using the torque anyway.
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post #9 of 20 (permalink) Old Jul 24th, 01, 06:06 AM
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<BLOCKQUOTE>quote:</font><HR>Originally posted by davidpozzi:
Dennis,
That cam was designed to help the 302 build more low end. But it wound up in the LT1 when the 302 was discontinued.

I bought an LT1 with that cam and drove it for many miles.
I later changed to a mild Crower cam and it had a LOT more low end and better top end too.

The factory cams seem to "come on" at 4500 and up.
The Crower I used came in good at 2500 and just pulled and pulled all the way up to 7000 in my 350. I guess my point is, you can buy a better cam nowadays that will run better on a street engine.
David
<HR></BLOCKQUOTE>

Do you have the specs on the LT1 cam David? I know it's a dual pattern .465(I) .485(E) lift but is the duration about the same as the 30-30? In the 70 Z/28 the LT1 was rated 360hp and other than the cubic inches and cam I believe it was the same as the DZ...

My thinking was it would keep the DZ sound but make power sooner!!

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post #10 of 20 (permalink) Old Jul 25th, 01, 01:23 AM
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GM spent millions developing there cams and combinations. Most aftermartket cam companies will tell you to run headers with it. I run the original solid cam from GM in my LT-1, wouln't put a different one in for anything. With stock exhaust manifolds,2.25 pipes and the single crossflow the car has gone 13.22 and on BFG Drags high 12's. Put the stock one in! It was designed for that motor and trust me, you won't be disappointed!
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post #11 of 20 (permalink) Old Jul 25th, 01, 08:28 AM
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The LT-1 cam is a good replacement - not as peaky, makes better torque down low, still screams at higher rpm. Put a 350 crank and pistons in it as well and you've got an LT-1 that only you know about

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post #12 of 20 (permalink) Old Jul 25th, 01, 05:33 PM
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<BLOCKQUOTE>quote:</font><HR>Originally posted by ICamaro:
I have plans for restoring a '69 Z-28 with the DZ302 small block. I have read and heard quite a bit about the lack of bottom end torque from the 302 and the great rush of top end power. Since camshaft technology has greatly advanced in the last 32 years, do anyone have an opinion on a replacement cam which could improve the low end of this motor and not sacrifice the high end? I'm planning on keeping the original 186 heads and the 11:1 compression (looking into piston coatings and other tricks to make it work on 92 octane!).

Thoughts?

Thanks in advance,

ICamaro
<HR></BLOCKQUOTE>
with 3.73,s and a stick, i wouldn,t worry much about bottom end.
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post #13 of 20 (permalink) Old Jul 25th, 01, 07:33 PM
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LT1 cam, #3972178
Specs are at .050" lift.
IN LIFT .452
EX LIFT .455
IN DUR 229
EX DUR 227
this was a pretty good cam in my 67 with LT1. I ran a 12.88 quarter with poor traction off the line.
But I put in a super mild Crower rated at 2500 to 6500, and had much better low end and it pulled an 800 Holley DP carb on top end where the LT1 cam would not take it.
I never ran the drags again but would estimate it was at least a half second quicker with the second cam.
The cam I used was a short track grind made for a wide rpm band.

With the 302 you gotta watch out or if you get too much cam, the bottom end will go away.
I distinctly remember driving a stock Z/28 and it coming on at around 4500 and the ignition would typically break up around 6000.
With good points and tune it would rev higher, but it was difficult to keep running well with the point ignition. The points seemed to go away quickly. I know the Z/28 had a different profile breaker cam and that might have caused some of the short point life. Also most engines didn't rev that high to where the problem would show up.
I used to buy the D-112P point sets and they came in the little cardboard container with tin top and bottom, you pull the string to tear all around the center to open them.
Later they came in a foil box. I've still got some of each. Anyone know if they are still available?
David


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[This message has been edited by davidpozzi (edited 07-25-2001).]

[This message has been edited by davidpozzi (edited 07-25-2001).]
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post #14 of 20 (permalink) Old Jul 25th, 01, 08:00 PM
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Oh, and pocket port those heads! It will make a big difference in power.
David

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post #15 of 20 (permalink) Old Jul 26th, 01, 04:02 AM
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Man, if you have the 302 for your Z/28, install the old 30-30 and 3:73 or better yet 4:10,s and just go out and rev like I say "I don,t need no stinkin'low end"
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