Build: 1971 2 Barrel 350, apparently only 63,000 miles. Car it was from looked pretty nice, so it's believable. Stock Bore 3.0/181 v6 pistons, about .094 in the hole, .042 head gasket. I believe it's about 9.6:1. stock rods, reconditioned stock crank, .010/.010 .002 clearances on the dot Underdog 350 timing cover, still doing great stock heads, surfaced/valve job TA DP intake EverydayPerformance 17057241 800cfm Qjet, further tweaked by me. Hooker 1103hkr headers TA HEI, 34* all in by 2700rpm TA 310 cam 2.5" dual exhaust, straight out the back, no mufflers. Relatively mild build. Made 247hp/274ftlbs to the tire on a mustang dyno. That's within 3hp and 1ftlb of my personal guess, so I'm pretty content with that. This was mainly just a curiosity run, wasn't chasing any particular number. Secondaries were opening pretty late, according to the dyno guy as he was standing there watching the carb they didn't open fully until 4300rpm. And I can tell they need to open sooner as well, given the gasoline stains on the air doors. I believe that is the cause for the sharp dip in AFR reading (purple line) that the graph shows.
And, for comparison, my previous engine (rip) was a very high mileage 3x reringed '70 SP 350 that was bone stock at the time of it's dyno run besides a crower level 3 cam, .042 head gaskets, and that same TA HEI but only 30* of timing, factory intake, manifolds, terrible exhaust with chambered mufflers, etc. That combo made 211hp@5003rpm and 263ftlbs@2700rpm.
Imagine what big valves would do. And figure static loss thru drivetrain. Of 30-40 hp . So easy 280-290 hp.
I think its all 3 variables layered on an incorrect scale, or a glitch. i dont really know. the last run i did 2 years ago the graph was normal.
Midstate machine. East side of dsm. In between the fairgrounds and firestone plant. That general area.
I can confirm this combo is faster than a 2020ish v6 challenger. I'd post the video but itd be considered exhibit A.
80 for a one and done but both times I went they Tbh were just curious because it's a sbb so they did a few. Normally its $100 plus more per hour if actually dping some tuning I can confirm that a single snorkel air cleaner made less than 3hp in difference in power vs no air cleaner.
Reviving this old thread. Put more timing in it for 36 total, leaned out and loosened the secondaries, added some thrush welded chambered mufflers. Made 217hp/250ftlbs. Loss of 30hp and 24 ftlbs from last time. Pics are overlays from last time plus this time and the second is just the most recent one by itself.
Referring back to the dyno power graph in your post from 2020, that dip in the torque band at around 4000, I have seen that many times before. It's caused by the valve springs loosing control of not only the valvetrain, but themselves also. During times in the rpm band where such takes neither end of the valve spring is in contact with anything! While the additional timing may be responsible for some of your drop in power your Exh system is having a effect also.
WOW .094 in the hole? If you believe it “about” 9.6 to 1 its probably “about” 8 to 1 There nearly bottom of the bore Did you do any calculations using the flat top pistons? What is your rear gear in your Regal? Or track time.
3.42 gears, 2500 Hughes off the shelf converter. Every compression calculator I use puts me about 9.2-9.5:1. I'm using the flat top 3.0 pistons.
