390 Dyno Run

[R-WEST]

Got the results from the 390 dyno run today!!
I've discussed the build in various posts (.030 over 390; 10/1; Ed. ..69's; port matched to plenum modded Streetmaster; 750 Quickfuel; Comp 282S at 104 c/l; Faron'ized Duraspark with MSD Streetfire - it was run with MSD 6AL on the dyno).

I couldn't figure out how to fit it all on one pic, so I stuck 2 in here.

Their A/F sensor must have been on the fritz or something. 



Dunno if the EGT on #7 is an anomaly, or if that's common.

Anyway, what do you all think?

Jay - I posted this over in the "Member Projects" section, too - if that's sucking up too much bandwidth, please delete the one over there.   

[ScotiaFE]

Looks like you have yourself a healthy 390.
Get some fresh rubber.

[fastback 427]

I think that's gonna throw that little truck around pretty good! Great numbers on a mild build.

[KMcCullah]

Where did the timing end up? Did you play with jetting at all? Without A/F data jets would have been tricky. I'm not good at cipherin pyrometer temps.

[jayb]

That is a nice street 390!  Good combination.  No problem posting the pics in two spots, by the way.  On the exhaust temps, its not unusual to see one or two temps off a little from the others, but that #7 is off by quite a bit.  I'm not sure why that is, but I guess I wouldn't worry too much about it, as long as the engine runs well.  I'd keep an eye on the #7 plug though...

[R-WEST]

I'm probably over-analyzing this, but I can't help thinking it's a bit too 'peaky', especially for a pickup, even though the thing is fairly light (3,600#).  I'll be running the wide-ratio C-6 gearset, 2,500 T.C. and 3.70 gears, but I keep thinking maybe the small Comp Thump'r roller would still give me the "sound" I'm after, and pump up the bottom end a bit more..    While a lot of purists don't seem to like them, they actually have a rep for doing a pretty good job.  I think Barry R mentioned one working really well in one of his dyno runs. 

And, it'd be a lot easier to do the change while it's still on the engine stand than after it's in the truck...

My wife just sits and stares at me when I talk to her about this stuff, so I figured I'd mention it here, where guys are more understanding about such things. 

[Barry_R]

Pretty good looking string of numbers there.  A little higher than I see at home, but well within spittin' distance and very realistic.  Depec acquisition software too - I'd like to add that to my setup someday when my checkbook heals up from the beating I gave it with the cylinder head project.

My history on 282S engines should be peaking a couple hundred RPM lower and carry out a hundred or two higher.  Probably an artifact of the Streetmaster intake, although the earlier higher RPM fall off surprises me just a little.  Could be just a tuning thing though - timing or mixture could easily extend the band by such a small amount. 

Personally - I'd run what you've got and tune it in the car.

[Qikbbstang]

Would it not be normal for the Dyno Operator to note #7s numbers were off and do a pull with two-pyrometer probe wires swapped to simply insure it was not his pyrometer/equipment and not burden the owner with a goose chase?...
   

[jayb]

Good point, BB, that would be the normal procedure.  And those thermocouples can be real flaky, so the low reading on #7 may indeed be related to the thermocouple.