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Discussion Starter · #1 ·
If you had the choice to run an 8-71 on a billet head motor or a 14-71 on a non billet head motor which would you choose and why?

No superman or psi's.
 

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T/S 368E
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No expert, but I would base that kind of decision on total combination & power levels attempting to achieve.
Too big can be just as bad as too small, for the combination.

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depends on the ci and 871 on a 540 is to small.
on a 454 it's fine.
i got one, i know.
871 on a 540 with m2bb2xcnc head and it won't make enough boost , only 15 lbs 20% over driven.
head flow also makes a differance also.
 

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LOVING LIFE
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depends on the ci and 871 on a 540 is to small.
on a 454 it's fine.
i got one, i know.
871 on a 540 with m2bb2xcnc head and it won't make enough boost , only 15 lbs 20% over driven.
head flow also makes a differance also.
20% and 15 lbs is pretty good, just means your motor is USING the boost instead of traping it in the intake. Turn that bitch up son. Mine is 30% over on a 509 with BMF heads making 18lbs. We have run fast with an 8/71 let it eat. You can spin it 40 over you got a long way to go yet.. The difference between 30-40 is HUGE and the difference between 20 and 30 is even bigger.. I can go about 48 over on mine but I will probably have my hihelix on it before then...
 

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Lord of Lords
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hmm something don't sound right there... I'm runnin 4% over and make 20lbs on a 10-71 SBC...
 
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