1. That cam should pull much more vac than that. I believe you have another issue if your vac does not exceed 7 inches.

2. If you are dead set on getting rid of that cam, you can use the LT-1 cam from 1970. Federal Mogul used to make a great copy of it, but they were bought out a couple years back, and I have no idea if it is still available. I would guess someone make a good copy of the LT-1 cam.

3. If you want many years of trouble free, go with a good hydraulic roller. Contact Chris Straub; tell him what you have and get a recommendation.

 

Thanks for the response. I’m trying to keep the car as close to original as possible hence the solid lifter cam. This morning I spoke to Fed Jones @ CompCam and told him 5-7 inches of vacuum he said “That is about correct for that camshaft...it does have a 247/254 duration @ .050"...that is not a vacuum producing recipe...”. I thounght I had a vacuum leak at intake.

 

Dev....I have a Crane repro 30-30 cam in my 302Z motor. It gets me about 10.5-11.5 in/hg at an idle of 1000 RPM. Timing has an impact on this. Make sure you have vacuum advance connected to the manifold, for full vacuum, not ported. It makes a big difference. Also, initial static timing needs to be 10-12 degrees minimum.. Also, make sure the valves are set at.026" cold. There is an article here that explains it in detail and why's and wherefore's. Start there.....check with Camaro Research Group for the articles on setting valves and timing.

 

Thanks Chuck. I’ll head down that path. Appreciate the help.

 

Scratch what I said in paragraph 1 above.

I was thinking the cam you had was 12-107-3. THAT cam was made as a direct replacement for the original 30 30 cam in the Z/28. It is close enough to the original that it is legal for the stock classes in NHRA. Jerry McNeish uses one in his record holding 67 Z/28 and runs mid 10s.

The one you have must be based on one of the off road cams that were offered over the counter. That would explain it. Don't know if it is a copy of the 140 cam (in which case you should still have more vac) or the second desing 754 cam, which is just too radical for a street car. I have no idea why they would market it as a "30 30 +" camshaft. That is a bit misleading, as only one camshaft was ever known as the 30 30 design. It was used in 327 prior to the 302, but all three years of the 302, that is the cam used in the Z/28.

You may be happy with12-107-3. It would still give you the great sound, and would definitely pull more vac than you are getting.

 

Thanks for the follow up. I’ll check to see if the 12-207-3 is avail e. You’ve been a great help.

 

get timing sorted first. you should still have more vacuum with your existing cam. i've been down this road as well and fine tuning the timing, A/F ratio brought me 13" vacuum from the 7 i was getting before. once tuned right you'll probably love what you already have

 

I used to get 7” of vacuum max with my 302 that has a stock 30-30 cam (I think from Elgin) and stamped steel rocker arms. I had a hard time getting it to idle well and make good power. I also was getting about 150 psi when I did a compression test. I used the .026” cold lash procedure for when you have factory rocker arms that aren’t really 1.5:1 ratio.

It turns out that I have Howard’s cam long slot stamped steel rocker arms that are really 1.5:1, so I adjusted my valves to .032” cold and now I have 9” of vacuum and 180 psi compression. It idles good now and makes much more power.

 

I used to get 7” of vacuum max with my 302 that has a stock 30-30 cam (I think from Elgin) and stamped steel rocker arms. I had a hard time getting it to idle well and make good power. I also was getting about 150 psi when I did a compression test. I used the .026” cold lash procedure for when you have factory rocker arms that aren’t really 1.5:1 ratio.

It turns out that I have Howard’s cam long slot stamped steel rocker arms that are really 1.5:1, so I adjusted my valves to .032” cold and now I have 9” of vacuum and 180 psi compression. It idles good now and makes much more power.

Thank you very much. Appreciate your input.

 

Good reading material for a beginner here.
Camshaft Selection - Specifications, Tech, Overview - Hot Rod Magazine

 

Good reading material for a beginner here.
Camshaft Selection - Specifications, Tech, Overview - Hot Rod Magazine

Thanks. I am a beginner. Should be great reading. Lots to learn.

 

Just remember, the longer the valves are open, the less vacuum created.
You're welcome. Don't understand something, ask.