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406chevelle 03-19-2006 11:37 AM

Why straight plug heads and angle plug heads
Why are there sbc straight plug heads and angle plug heads???
It seem that most common headers accommodate the straight plugs.
I have chance to buy a set of AFR 210cc angle plug heads for a good price, but the available headers for angle plugs seem limited for a 72 chevelle.

Any pros or cons to straight versus angled???

MI2600 03-19-2006 11:45 AM

I have heard (no personal experience) that the angle plug heads add a very slight amount of oomph at high rpms. The theory is that the plug is pointed toward the exhaust valve for better combustion.

My take is that if they were so much better then all race heads would be angled.

1971 Chevelle 03-19-2006 12:07 PM

I always thought you could order either because of header clearance issues. :confused:

poncho62 03-19-2006 12:18 PM

The angle plug heads were an experiment from GM in the late 80's, I believe. On a street car, there is little or no advantage to them.

xntrik 03-19-2006 12:21 PM

Plug angles are coordinated with chamber shape for better flame travel, etc. Time passes, ideas change, and so does technology. Some heads also have the plug moved over sideways to center the spark tip. Ideas like extended tip plugs have the same effect to help center the flame travel.
In reality, there is only minimal real world differences in most all the heads.

If you can't get headers, don't get the heads.

67 Deuce 4 Me 03-19-2006 12:33 PM

I have used both on my nova. I couldnt tell any differance in performance. But I will never own angle plug heads again. Because they were a nightmare to change plugs in my Nova.

automotive breath 03-19-2006 12:36 PM


Originally Posted by 1971 Chevelle
I always thought you could order either because of header clearance issues. :confused:

AFR has part numbers for both straight and angle plug heads. Because very few people order the straight plug 210 SBC head, request for them must be handled at the beginning of the machining operation (special order = longer delivery times). The result is fewer used straight plug versions.

As for the advantages of the angle plug on the street, it's not enough to notice.

406chevelle, The AFR 210 is an excellent head, if you can make them work, buy them your 406 will love it.

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