5.5:1 or 6.1:1 High Compression Heads?

[modelAtony]

Originally Posted by chap52

Working with a basically stock motor. Other than the obvious increase in horse power with a new high compression head, what are the pros and cons of the addition? Secondly 5.5 vs 6.1 pros and cons.
Just getting into these engines and would appreciate your in sites.

I say 6.1 you will like it.

[sphanna]

I asked this same question a few weeks ago. Did not get any response then, so I am grateful for this thread. I have a 6:1 and can think of no reason to prefer a 5.5:1 as both seem to be satisfactory with neither having a significant advantage over the other. I just wondered why the 5.5:1 was the most popular. I have the 30 fordor and added the 6:1 head. Wow, what a difference!!

[chap52]

Thanks" sphanna" for sharing your experience. I think that the %.5:1 has been available for a longer time. They are so close in cost that it seemed to me that the 6:1 was a better choice if it wasn't a problem mechanically.
I have lots of time to decide.

[Purdy Swoft]

I have been running 5.9 compression ratio heads on three of my engines for many years with good results. If I ran Snyder Heads I would use the six to one head. The most important thing is to never lug the engine . If a person doesn't know how to properly use the spark it would be better to use an automatic type advance distributor. The owners manual says to run full advance at speed and that is what I have done for over 50 years and never had a problem. If you hear timing knock retard the spark as necessary. Lugging usually happens when running too slow and straining the engine in high gear . I keep the momentum built up when approaching hills . I'm not telling anybody what they should do , thats just how I drive mine .

[chap52]

Here is a great piece of of "head" info:
http://www.fordgarage.com/pages/head...ssionratio.htm