[DENCOUCH]

Are the Poncho 5c-4 heads any good?

Everything I read appears to hype the 6x heads, but I never read a thing about the 5c.

They came on the 400 I have, and I was told it is a '74 motor.

[ericnova72]

You can look on Stan Weiss' cylinder head flow database site(Google Stan Weiss), but all the Pontiac D-port heads are within a few cfm of flowing all the same.

Why the 6x got so much hype I don't know...maybe the most common?? or just the association with the TA in the Bandit years(hype)??

the 5c-4 will serve you just as well.

[cobalt327]

I never saw a 5C-4 head, personally- but then I don't get out much. The only mention of them a casual look gave me was Butler has them (5X) as:

5C,5X,5G '75-'76 455, SOME 350 93cc-114cc+ D-Port 2.11"/1.66"


The 6X-4 head has a smaller than most chamber, screw-in studs and guide plates, they can be easily found cheap, thus it's popularity mainly among 455 builders.

Be sure of what the chamber size actually is. While they do have 1.66" exhaust valves, this isn't much of a hindrance until higher than usual output is required, besides the heads will accept 1.77" exhaust valves if they're needed/wanted.

[WDCreech]

Here's some info on them: http://www.wallaceracing.com/headsearch.htm
2.11" intake, 1.66" exhaust, screw in rocker studs, and rated at 93 cc. Very good head for a larger Pontiac engine to use pump gas.

[cobalt327]

Originally Posted by cobalt327

I never saw a 5C-4...

Supposed to be "I never saw a 5X-4...", like the title of this thread.

5C heads are common, at least in the bigger scheme of things. Regardless, chamber size is important and should be measured.

As long as there are enough holes (or meat to drill any missing holes) for headers, the valves are at least 2.11" x 1.66", they have screw-in studs and guide plates and the chamber size is acceptable, ANY D-port Pontiac head will suffice.