I have a '75 with an L-88 spec 427. When I purchased this car earlier this summer, it ran hot as heck. Temp gauge was always at 200 and could be more at extended idle. I had never checked the timing prior to rebuilding the distributor. I have now added vacuum advance and am running 36* (18* initial and all in at about 2000 or so) with another 14* of advance above 7-8" of vacuum.

The car certainly idles a whole bunch better with the vac advance. Because I only had the car for a short while before doing this change, it is hard to say if I am getting more or less power than before. It feels as though it is slightly less power, especially at lower RPM's.

With these changes, I now am running way under 200 degrees. With the stock gauge, it is very hard to tell exactly what temp. However, it seems that it is around 180. It stays at this temp even when pushed hard.

I am afraid that maybe I have put in too much advance and am losing power due to this. Should I be concerned that I am not producing as much HP and that is why the temp is so low? Any advise on adjuting for max power? Could this be a mixture issue? I have adjusted Idle mixture as best I can and don't know what jets are in my Holley 850 DP.

I should add that the engine just drinks gas. I can't be getting 8-10 MPG. I am not sure if this is to be expected with this engine or is tied to an over-rich condition that is tied to the excessively cool running.

Thanks for any guidance you may have.

 

8-10 mpg might be about all I would expect from a bb. Your timing sounds right, although perhaps stiffer distributor springs would cause timing to go all-in at higher than 2000 rpm. Maybe you could shoot for 2500. When you set your fuel mixture, how did you do it? I believe Lars would suggest that you monitor your manifold vaccum and set mixture at highest attainable vac. ?

 

Vacuum advance will not affect peak power - there is no vacuum advance when the engine is under power. Your timing looks good.

 

I adjusted Mixture for best vacuum. I keep bending the springs trying to force it in later. I will bend them a bit more.

Any reason for cool running temp? Should I be concerned that it is only about 180?

 

The cooler running temp now is because you were probably running with the timing too retarded previously. That causes an increase in engine temps.

 

My question is, why would you think 200 degrees is running hot?

If this engine has L88 compression I would think the timing curve is a little fast.

BigBlockk

Later.....