Firing order swap ?

BBC blown alky.

Anybody try:

4 & 7
or
4 & 7 plus 2 & 3

???????????????

 

I did the 4-7 no power gains that I noticed. Didn't run it on a dyno.It's suppost to help with harmonics more than anything. Maybe freeing up some small hp figures. Hell everything helps.

 

I was told no power increase, but it did helps with "shakin"

 

any one notice less harmonics in their engine?

 

Did MANY Dyno pulls and 4/7 made ZERO HO difference....just "sounded" different!

 

Did you notice any improved harmonics? Anything noticeably different about the way bearings and associated parts wear?

 

Not really....we went to all Std firing just to avoid confusion when doing motor swaps between rounds.

 

for us the 4 7 swap does nothing exept keep us on our toes when doing mag/cap/lead swaps,
521 legal hemi

 

No power increase, but was told (by Chase Knight) it is a good thing to do, as it reduces the stress on the rear main cap on a BBC, so we did it for the new A/Fuel engine.

 

I run a 4-7 swap blowen alcohal 540 bbc. thats the only way its been run, so can't say it builds any better power than standard. But I have a friend that build a bunch of late model dirt car motors, (sbc) and he runs the 4-7 swap on all of them. He seem to think it makes better touque #'s. Can't prove anything by me though.

 

No power advantage in the blown applications.
They say it is a little nicer on the crank, but can't find anyone with proof.
Now in an open plentium, naturally aspirated deal there is power. Especially with non/splits.

 

http://www.aera.org/ep/downloads/ep8/EPQ409_52-56.pdf

 

That's some pretty good reading right there, basically saying what Chase (from Crane Cams) told me, but in 10 words or less