1st design off road cam #3927140 Vacuum Issue?
 

Hi Everyone
Rebuilding my stock 302 with all the original parts, pink rods, 1178 crank, 0 rockers, 11-1 stock pistons, single DZ carb etc etc.
Can I use the 1st design off road cam #3927140 in this stock engine for street use with 410 rear.
Can I still use pump gas 94 And is it possible to have a vacuum problem at all?
Thanks very much in advance for your help.
Ken

Re: 1st design off road cam #3927140 Vacuum Issue?
 

My JL8 has that same cam seems to work fine I actually like the bleed with the overlap seems to be a bit of a ease with the comp ht. with pump gas, no ping brakes work great!!

http://i226.photobucket.com/albums/d...lass/my69z.jpg

Re: 1st design off road cam #3927140 Vacuum Issue?
 

In the mid 70's I built an LT1 with that cam and had it in a 69 Camaro with power disc brakes. Had no lack of vacuum for the brakes, so you should be fine.

Re: 1st design off road cam #3927140 Vacuum Issue?
 

A guy on camaros.net just put one in his car along with headers and he loves it. It really sounds strong in his video. I think he has a gardeners chambered exhaust too.

https://www.youtube.com/watch?v=WTgT0VCytGc

https://www.youtube.com/watch?v=iXK-lTkRXBY

Re: 1st design off road cam #3927140 Vacuum Issue?
 

4:10's may be a little tough to pull out with the car. Unless the trans was a M20 box. I would go to 4:56's with an M20 box and that car would be mean. Also I like pressed in wrist pins. A little safer and it doesn't have much, if anything to do with performance. 302's are all about proper gearing. We already know how much they rev! https://www.yenko.net/ubbthreads/imag...ins/3gears.gif

Re: 1st design off road cam #3927140 Vacuum Issue?
 

My brother had a stock, except for the off road cam, 70 1/2 Z-28. 4 speed, 4.10 gear. It was fine with power brakes, had a great sounding idle, but 4.56 gears would have been better with that cam.

Re: 1st design off road cam #3927140 Vacuum Issue?
 

I agree, a steeper gear would be better...I had 4.88's in my 69 Camaro.

Re: 1st design off road cam #3927140 Vacuum Issue?
 

Now we are talking. On a sb chevy most people play under the hood instead of playing under the back end! https://www.yenko.net/ubbthreads/imag...ins/3gears.gif

Re: 1st design off road cam #3927140 Vacuum Issue?
 

Thats the cam i put in my 302 back in 1990,its been foulen plugs ever sence,turns out that was a good thing because i never drove it.just wondering if the primary jets is the cause of the engine running so ritch..

Re: 1st design off road cam #3927140 Vacuum Issue
 

I ran that cam in my 302 for a number of years and loved it. Never had a detonation problem using pump gas premium but it did tend to foul plugs. I drove this car as a daily driver and would change plugs about every 1000-2000 miles. No vacuum problems at all. My engine was stock other than headers and the cam, and I was running 4.10 gears. I think 4.10 gears were great with that engine. Best to run 302s with a 4-series gear. I don't think you should run the 140 cam without headers. Chevrolet certainly did not recommend it back in the day. Is that what you are considering?

-Jon

Re: 1st design off road cam #3927140 Vacuum Issue
 

If you were going to change your stock 302 cam out of your Z at this point would you replace it with a better, higher lift/duration after market unit or something like an NOS 140 cam? Which would be faster and better suited. Do you think maybe Comp Cams makes a better all around suited performance cam than the 40 year old Chevy design? Thanks, Sam

Re: 1st design off road cam #3927140 Vacuum Issue
 

Have seen reports on this G. Sommer's Z28. Car appears to be very fast and set up by McNeish, runs in the mid 13's with street tires and closed exhaust?