one of the local guys kids came by yesterday to get a bit of help tuning his new SBC engine, its a basic 350 and he installed a comp 268 cam and its got headers but not much else, it runs fairly decent from about 3500rpm on up to about 6000rpm but it lacks lower rpm torque, hes got a wieand 7546 single plane intake on it he bought for $60 at the swap meet, but it came without the divider plate, that intake usually had for mild cams, most of the younger guys have never seen that as most of the guys pitched those removable divider plates or just lost them.
NOTICE THE MILLED VERTICAL SLOT TO HOLD THE DIVIDER PLATE
http://www.holley.com/9008.asp
heres the factory divider plate, which also requires a bit of trimming to fit exactly correct in the plenum,
now that was a common intake back in the day, but we learned a trick that I got to use yesterday
the factory divider plate does work and does add low rpm torque you can feel in the seat of your pants driving but we found that if you replace the factory divider with a plate cut from perforated steel the same size, with about 1/4" holes, it works just a bit better.
IT usually tends to increase the vacume reading the power valve sees, and the divider usually works best with cams having LESS than about 240 DUR @ .050 lift
a true single plane has a common plenum
a true dual plane has twin plenums with the runner firing order separated by 180 degrees
placing a divider in the plenum of a single plane intake gives you some of the good and BAD points of both designs but only testing and your tuning skill will determine if it benefits your particular combo, and in my testing a 4 hole divider or carb spacer of about 2" thick under the carb and over the divider helps the divider work at its best, but even with out the spacer youll notice a difference in the engine power curve
SINGLE PLANE
DUAL PLANE
http://store.summitracing.com/parts/edl ... dia/images
extended divider carb spacer
RELATED INFO
viewtopic.php?f=55&t=1038
viewtopic.php?f=55&t=109
viewtopic.php?f=55&t=1790
viewtopic.php?f=55&t=1639
NOTICE THE MILLED VERTICAL SLOT TO HOLD THE DIVIDER PLATE
http://www.holley.com/9008.asp
heres the factory divider plate, which also requires a bit of trimming to fit exactly correct in the plenum,
now that was a common intake back in the day, but we learned a trick that I got to use yesterday
the factory divider plate does work and does add low rpm torque you can feel in the seat of your pants driving but we found that if you replace the factory divider with a plate cut from perforated steel the same size, with about 1/4" holes, it works just a bit better.
IT usually tends to increase the vacume reading the power valve sees, and the divider usually works best with cams having LESS than about 240 DUR @ .050 lift
a true single plane has a common plenum
a true dual plane has twin plenums with the runner firing order separated by 180 degrees
placing a divider in the plenum of a single plane intake gives you some of the good and BAD points of both designs but only testing and your tuning skill will determine if it benefits your particular combo, and in my testing a 4 hole divider or carb spacer of about 2" thick under the carb and over the divider helps the divider work at its best, but even with out the spacer youll notice a difference in the engine power curve
SINGLE PLANE
DUAL PLANE
http://store.summitracing.com/parts/edl ... dia/images
extended divider carb spacer
RELATED INFO
viewtopic.php?f=55&t=1038
viewtopic.php?f=55&t=109
viewtopic.php?f=55&t=1790
viewtopic.php?f=55&t=1639
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