[scottj]

Scott,
I know, 434 vs. 358 = apples vs. oranges. Today 358’s aren’t really run in DLM. But, a couple of years ago when you got a 100lb weight break for running a 358 most guys ran them at the national level. The dirt guys borrowed all the Cup technology such as the same 3.335” stroke ultra-light cranks, the same piston guided rods, same gas ported piston/ring package, and the same heads if they wanted them. Also, we ran them sealed (vacuum) like the cup guys do. Power-wise, what we had was essentially an aluminum cup engine. The cool part was that Cup paid for all the R&D. What wasn’t cool was that with a 3.335 stroke and Cup heads it was too lazy off the corner for a dirt car. You had to turn it 9-9200 to make power but it also had to pull from 5000 to get off the corner. The solution was to use a smaller intake manifold, 15.5: 1 compression and more cam. I don’t have exact numbers but the torque increase was substantial. More important than the peak #'s was that the engine would now pull over a 4000 rpm spread.

When the weight break disappeared a couple of years ago so did the 358 and the search for how to get more power out of a cup engine for dirt use.

My original point was that there is no need to wait for the cup guys to develop cylinder heads if someone needs a more powerful head. On a 418 cid dirt engine the SC1 is around 40hp stronger than a Cup head and over 700 ft/lbs. More important than the peak numbers is the spread of power and the drivability since dirt cars are much more sensitive than asphalt cars with regard to power delivery. Most dirt engines could pick up 20 hp with a cam change but they would be undrivable.

RDI will direct anyone that needs the next step up from a cup head to Don Losito (Ultra Pro) and the SC1 head. They did me.
Sorry for the rambling, Scott