Another Q about gears

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swedefish

swedefish

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I have a question about how the gears in the third member would affect the
running of the engine?
The build is a
383 cid + .040
Square decked , pistons .022 down in the hole, steel shim gasket
915 heads with bigger valves
KB dished pistons
According to my calculation this would give a 10.2:1 in static CR.
MP purple cam 284/484
Eddie RPM intake
Eddie 750 carb
Eagle rods
4-speed tranny
Centerforce dual friction clutch

I´m running NGK XR5 sparkplugs, Is this a wise choice?

Now for the question, I´ve got a 2,76 in the rear. I know it´s not to any advantage with this gear, but would it be to any disadvantage making the car to run worse or.... on low rpm:s ?
Many thanks in advance
Lenny
 
Forgot, the tires are Firestone Redlines, diameter 25.7"
 
I imagine your a little boggy off the line, right? But probably can cruse 70 @ 2500 rpm. If you drive more on country roads and enjoy the occasional stop light gran prix, get a 3.23 or higher. and I prefer champions
 
mopar head said:
I imagine your a little boggy off the line, right? But probably can cruse 70 @ 2500 rpm. If you drive more on country roads and enjoy the occasional stop light gran prix, get a 3.23 or higher. and I prefer champions
Click to expand...

Thanks for the reply.
Yeap, you´re right about the boggy at low rpm:s.
 
That cam is gonna like at a min. A 3:55 gear and probably be best with a 3:91 or 4:10 especially in a 383. With a 2:76 or 3:23 at around town speeds it will be unpleasnt to drive. Will have a killer top end on the highway though... Lol
 
Well, considering that your motor will make most of it's power above 3200 rpm, I'd say that the 2:76 is a dis-advantage. You need to get that motor in the powerband as quickly as possible. A 2:76 is never going to get you up in that area of the powerband. You didn't say what car this motor is in, but even in an A-body, anything less than a 3:23 is not going to get your motor in it's sweet spot. Play with it a little, but get yourself at least a 3:23 (good), a 3:55 (better), or a 3:91 (probably the best). Good luck with your project, Geof
 
Thanks guys.
I appreciate your replies. :thumbup:
Almost forgot, it´s a -67 B-cuda Fastback
 
Depending on your highway driving?As cosgig said a taller gear 3.91,s will wake your car up around town,but will slow you down abit on the highway.Happy medium with 3.55,s.
 
Still got the bog at light throttle after setting the ignition timing. :banghead:
Dwell angle 28*
Initial at 18*@ 900 rpm, total at 34*@2200 rpm.
Vacuum hose connected to the ported side, however not when setting the ignition.
When I connected the vacuum hose it didn´t make any difference on the timinglight. Did try to retard the vacuum advance but I could only turn the screw in the dist about a half of a revolution
Set the idle screws for the highest vacuum, 11"
Replaced the acc. pump nozzles to 0.43.
Acc.pump linkage in the hole closest to the top of the carb.
Set the metering rods 2 steps richer at both cruise and power mode.
Engine specs in the first post of this thread.
The carb is a Eddy 750 electric choke

Any advice or other suggestions?
Many thanks advance
Lenny
 
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