Quote:

More questions:
1. Was the engine in the same state of tune when it made 720-ish HP on your dyno as when it cranked out 750+ HP at the EMC?

2. Why the major "fat" dip in the A/F ratio down low? My first thought was that big-venturi "True 950" Holley wasn't happy under a load down there, but would have expected it to be lean, not uber-rich...

3. Do the flow #s you posted reflect the head being positioned in an "adjusted" location over the bore fixture comparable to where it was on the engine w/ the offset dowels, etc.?





1. The engine was fattened up 3 jet sizes at EMC to adjust for the oxygenated VP100 fuel that I was unable to test with prior. I also added 2 degrees timing for a total of 38. This helped midrange torque and the average quite a bit. I did leave home with the tuneup with a little left not wanting to chance a last minute failure and missing the EMC altogether. That story is all too common. Once down there though I am willing to get aggressive with the tune-up in the search for points. I would have fattened it further and made a high speed bleed change if time had permitted.

2. The fat dip down low is almost always IME due to reversion/cam overlap just before it gets to its happy place. It was far worse before we added 18" collector length. We shortened them 2" and lost all of our gain. When we cut those off to extend them back we though if long was better then lets put 20" .Our collectors were about 2 inches too long. This engine was really cool in that it had 2 very distinct surges in it power band. I have video and you can watch the torque needle surge and level off then surge upwards again. You can try and make it leaner in that range but power will suffer just below it or above it or both.

3. Yes, My flow fixture-plate is doweled and the flow chart is exactly how they were flowed. Only thing I neglected to mention was the bore fixture was 4.375" diameter. In fact I think I may put 4.375" flat tops-which will put this somewhere around 14-1 and 470 cubes and see if 800 hp is not achievable. J.Rob

2009 PHR\EMC Competitor
2010 PHR\EMC Competitor
2011 PHR\EMC Competitor
2012 PHR\EMC Competitor
2013 PHR\EMC Competitor
2014 HotRod/EMC Competitor
2015 HotRod/EMC NoShow
2016 HotRod/EMC 3rd place SPEC Bigblock
2018 HotRod/EMC 7th place G3