This is really intriguing as I'm digging more. DB Z28 really got me wondering about larger port and whether a larger motor, 383+ can perhaps still handle the larger ports and make good low end torque.
I found this article searching around. Speaking about matching larger ports to larger engines...
"While greater port size does not guarantee increased airflow, properly matched port size and design promotes increased airflow without sacrificing velocity. This equals improved torque."
The cam they're using is only one step bigger than mine, however I'm currently running 1.6 rockers so my lift is roughly around .500+
http://www.superchevy.com/how-to/eng...formance-test/
I also noticed in the GM performance parts catalog the ZZ383 engine with a relatively low duration cam and their 210cc intake port heads makes 400 ftlbs at 2000 and up to 450 at 4500. Talk about a flat torque curve, even with "big port" heads. It peaks at 435 hp at 5500. Man that sounds like a great reliable autoX/ street driver engine...
http://www.chevrolet.com/performance...ck-zz-383.html
Lance- If you're talking RWHP then you're roughly about 480 ft lbs and near 400 hp at the crank, that's pretty impressive and sound like you're almost there. All the numbers I'm stating so far including my current engine are crank numbers. Your heads are Vortecs? Maybe they're choking you out as the rpms rise?
Thanks for the ebay link Che70. Looks like those heads have everything I'd need done to them except drilling the steam holes for the 400. The question remains then will the Vortec heads have
too small ports for the bigger motor?