I've been curious about this for awhile. Besides the obvious difference of one of one them being at an angle and one being strait, what are the differences between having a strait-plug head or an angled-plug head? Does it have something to do with performance or application or what? Anyone know? Thanks.

------------------
'89 Firebird Formula 350
L98, WS6, Red/grey, t-tops, and a 3.27:1 rear
K&N, TB bypass, no MAF screens, CAI, full Accel ignition, no cats, Hooker Supercomp shorties, Hooker 3-inch catback
ET? 14.19@98.9mph (G-tech)
(Corrected for G-tech 'extra' 6mph)
Also own '83 Firebird 2.8 2bbl. 155K miles.
ET? Break out the calendar!

 

Theoratically an angled plug head locates the plug tip at a more favorable spot in the combustion chamber, resulting in a better burn and more power. In reality, most performance gurus I've read agree the effect is negligable if any. Just makes plug clearance trickier.

------------------
"American made baby. 100% American iron. The muscle among the masses. My hero. Yep, you can take your ergonomically designed, space age, computer controlled, 4 door, cup holding map lighted split double wishbone split fold down retractable cargo covered moon roof piece of transportation and keep it. For I have felt the thunder. And I know the difference!"
JSP Motorsports
ICON Motorsports

 

I agree with Jester as to the theory behind angle heads (and the reality).

The main reason to select one over the other is primarily spark plug clearance when you install headers. With stock manifolds, straight plug is better; with headers, often angle plug are better.

It is always best to talk to the head manufacturer about the particular headers you have or planning to get. Some heads work fine/okay with some headers, and not so great with others. Others are just a pain in the butt, no matter what.