I would like to build a factory SBC chevy and I have decided to build a blueprinted 1970 Lt1 for factory drag racing. Is there any advantage to either of these cams. I have heard that in order for that engine to get to the 370HP chevy had to use the 30-30 cam. In the class we run, headers are aloud so the old cars can be competive with the newer cars. Does the addition of headers let the 30-30 run over the 178 cam? I just want to be able to keep up, 12.6's or so is about the fastest car now.

Anyone have any factory times for a 1970 z28?

Moe,

The deal as I have read is that the 30-30 cam was the 350 mule engine cam that got the 370 hp out of the LT-1 motor, and I forget if it had a dash in the name or not?

(One point I don't know here is if GM ran the Vette, 2.5" ramshorn cast-iron exhaust manifolds on the mule engine b/c they alone would probably be good for maybe 10 to 15 extra horses above the stock 350 log style...)

The -178 cam was next installed due to the new Z-motor being hooked to an automatic for the first time b/c the 30-30 was too rough to use.

I do know that to use either of these cams plus the old -151, 350hp/327 hy- cam you need at least 11 to 1 CR. b/c that is what makes them cook!! I ran a -151 in my STOCK, -67, L-48, 350 and it ran very well and I think it was b/c of the longer stroke b/c it was only at 10.25 to 1 CR. if that??

I personally would use a solid cam designed for max. midrange and for about a 9.5 to 1 CR. using cast-iron heads and right at 10.0 to 1 using aluminum heads even though you CAN squeeze more from them.. (Like a half point up in CR.???)

The good old CC 282S solid cam falls right in this b/c it is a 2,000 to 6,000rpm use cam..

Pease consider this type engine but if you have your heart set on a legend, then by all means build it with the great old 30-30 cam, but be ready to feed her good gas due to the needed CR.!!!!

pdq67

PS., I haven't mentioned the newrer, modern designed solid cams but feel free to use one of them if you really want to..

The -178 LT-1 cam was an improvement over the "30-30" cam. The LT-1 cam has similar exhaust timing but much less intake timing so it has more low end torque. The LT-1 will have more power and torque anywhere below 6000 RPM while the "30-30" will start to have a slight advantage at engine speeds at and above 6500 RPM all else being equal. The LT-1 is a great solid lifter cam especialy if you are running on the street. It is also good if you run through an exhaust system because of the dual asymetrical lobe pattern.

I believe GM was quick to stop marketing the old "30-30" cam as a Heavy Duty Service Part because the other cams they had were so much better. My old copy of the Chevy Power Manual did not even list it as of the late 70's but still had the much older "Duntov" cam, "151", "178", "First Design Off-Road", and "Second Design Off-road" cams as well as other several other cams. The GM engineers I have talked to all said it was basicaly a poor design. That being said, I actualy chose to install and run one in my own car because that's the way they were built originaly and I was shooting for "authentic" graemlins/clonk.gif

If you have limitations on modifications and want to spin very high RPM's, the 30-30 is a cantidate but probably not the best choice. If you are allowed to run it, I might suggest you look at the -140 First Design Off-Road cam. 12:1 compression is advised and it will probably out-run either of the other 2 cams at the track. You will need lots of gear for that cam but it should do the trick. smile.gif

-Mark.

I do love the power of the newer design but in my mind when I pop the hood I will be saying its just another modified 350.

I want to say, yup its bone stock 360HP LT1 which was and still is one of the hottest stock engines ever made. I just want to make sure I dont make an *** out of my self by racing 440's, 396's and 429's. If thats the case I will build a 396 if that is what I have to have to win. I think a blueprinted LT1 would do the job, I think with headers, port work, fine tuning the 350 would be right at 400HP at the fly wheel. Thats around 320 at the wheels and should get me around a 13.0 to a 12.5 in a 3500LBS 1970 camaro.

Its just how can I get the 400 at the flywheel with all factory parts and appreance.

What are the HP ratings that the alt, ps, waterpump take up? I think in 70 they tested the LT1 with just a water pump, and in 71 they dropped the compression and tested with alt and got 330HP.

IS my goal unreasonable?

Would you suggest installing the 178 LT1 cam 4 degrees advanced? It really cant compare with any modern grind with that 116LSA, I mean if you advance it its still on a 112 which is where most HI-po modern cams start. Maybe advance it 8 degrees? I personally think it is great to have stock cars, I love going fast too but you would believe the reaction you get when you say, "yeah she's all stock" Its so fun to race old GTO's and watch there facings frown when they get beat by a 302 or a 327. A 350 is getting on the edge of a "fun" underdog engine but I think it would be perfect for the street and nice daily driving. I mean with a 116LSA you should get 40MPH...

Thanks, oh how I love beating GarbageTruckOption pontiac's

Sorry, I can't tell you if you should run it other then per GM spec's.. pdq67

The -178 is ground about 4° advanced already. If you install it 4 degrees retarded where the intake centerline is equal to the lobe centerline, you will have the top end of the "30-30" with about 30Ft-Lbs more on the bottom end. Not a bad trade off. Pocket port the heads and run it!

-Mark.

Thx. stingr69 for mentioning that b/c I just hadn't thought of doing that.

Good Point!!! I bet if 1.6 to 1 ratio rockers are used on the intakes, it would help some too b/c the lift would then be up there like the 30-30..

pdq67

I ran the old 140 cam in a 11-1 350 with 3.73 gears and a 4 speed in a 72 Z28. That car ran high 12's on my street tires and was very strong and reliable. If I can find i'm going to put one in my 11-1 327.
Ron

Crane makes it pn 968821

I think it is SY1 that likes the old -140 cam in a high compression 302/306 type motor over and above the old 30-30.. Like around 12 to 1 CR. or so??

pdq67

Thanks for all the reply's, I love this old stuff..


The great thing about a gm cam is that it will last 100,000 miles too.