Sportsman II heads

[Kctom]

Have a set of World Products Sportsman II heads on My 388 chevy engine. Been running the accel shorty header plugs. They seem to carbon up pretty bad. Would like a little hotter plug. They take a 5/8 tapered seat type. Anyone have a good idea?

[Pope Downunder]

Have a set of World Products Sportsman II heads on My 388 chevy engine. Been running the accel shorty header plugs. They seem to carbon up pretty bad. Would like a little hotter plug. They take a 5/8 tapered seat type. Anyone have a good idea?

I'm not sure of your combination, but this article may be useful.
http://www.centuryperformance.com/spark.asp
Unless you can shut the engine down after a full power pass without slowing down etc., it is pretty hard to read the plugs.  You may just be running rich.

A friend of mine was advised (by a friend of his, who happens to be a technician with Shell) that the unleaded gas is harder to burn and the premium stuff is even harder, as it is more dense (or viscous?). It atomises nicely under high pressure fuel injection, but  doesn't do so, so well through a carb.  Also, without timing control (computer) we end up having to run lower compression, or advance.  so, we either go with technology, or we have to compromise.  My old 283 would run better on regular unleaded than Shell Optimax, but it would 'pink' ocasionally.  Then somebody said, try the BP Premium Unleaded, and it went better all round.

My interpretation on all this is we need to build our new engines to run on regular unleaded, and run a good ignition, like a HEI, or MSD to get the spark to burn the 'slop'.  With a HEI you can run around '045" plug gaps and with a stronger spark it should improve.  

So, my new 283 (actually a 313ci) has been built so the dynamic compression ratio and quench are right for regular unleaded, I've stuck with a mild cam, and am converting to a Quadrajet (from the Edelbrock -Carter 500 4-bbl), and fitting HEI into the old Delco dizzie (ditching the dual point).  I'm hoping for a much improved all-round performance, and a 5 mpg improvement in fuel economy.