Keeping It Original L79
Thread Starter
Drifting
Joined: Mar 2009
Posts: 1,461
Likes: 361
From: Monson MA
Keeping It Original L79
During my restoration I will get to the engine rebuild. I would like to keep things as close to factory as possible. The L79 had 11:1 CR. I am wondering based on all I have read, can I keep this 11:1 CR and run on 93 oct.? It is still not clear by the articles and comments I have read. Some say yes and some say no. I am confused. This same frame of mind seems to be the same with a couple of engine builder I have talked with. I have been told to install Aluminum heads and I should be able to keep the 11:1 CR. Please give me your input.
Burning Brakes
Joined: Feb 2006
Posts: 1,223
Likes: 4
From: Regina Saskatchewan
If you want to go as close to factory as possible - aluminum heads shouldn't be an option, but I've been told the same thing - yes aluminum head will allow you to 'push the limit'.
Again I'm no expert but from what I figure - the other thing that is important is your cam choice. The way I understand it - the more 'overlap' on a cam , the higher the compression you can run. Overlap being the time the intake and exhaust are both open at the same time - so you are essentially bleeding off pressures. Maybe some of our cam experts can chime in.
Again I'm no expert but from what I figure - the other thing that is important is your cam choice. The way I understand it - the more 'overlap' on a cam , the higher the compression you can run. Overlap being the time the intake and exhaust are both open at the same time - so you are essentially bleeding off pressures. Maybe some of our cam experts can chime in.
Instructor
Joined: Feb 2009
Posts: 159
Likes: 0
From: asheville nc
I have a 68 L79 and it has 11:15 to 1 compression...it seems to do okay on 93 gas but not nearly as powerful as it was in the early 70's...and I think I have mine at 12-14 BTDC. The last time I drove it was last april...before our state put that crap ethonol in the gas.
I am planning this year to put in some av gas...my friend who has a high compression 427 ford in has 48 PU, stops from time to time as a local small airport and puts in a few gallons...you can smell by the way it runs.
You may not be happy with lower compression sound and power wise.
Jimmy in NC
I am planning this year to put in some av gas...my friend who has a high compression 427 ford in has 48 PU, stops from time to time as a local small airport and puts in a few gallons...you can smell by the way it runs.
You may not be happy with lower compression sound and power wise.
Jimmy in NC
