RedTop Engine?

[Mux213]

matto,

Not 100% sure about this one myself but I believe the smallport engine came with the newer 7rib block which is stronger then the older 3rib block and can handle more power and it had some better lubrication due to some oil thingies they added to it. Don't know what to call em.
Also the head itself is a small port which flows the air better then the big port which means better power at lower RPM but theoretically less power at higher RPM so they claim its slightly less rev happy and because the internals are heavier (stronger) it has slightly slower throttle response.

So basically, stronger engine, more torque and power at lower RPM and over the rest of the power band, but slightly less revvy and slower throttle responce.

There is a good writeup on club4ag about the differences between the 4AG engines btw:
http://www.club4ag.com/faq%20and%20tech_...04A-GE.htm