I have stock flame arrester and was thinking of something less restrictive. Has anyone done this?
If so any rpm gain? Thanks

Absolutely DO NOT WASTE YOUR MONEY. I have EXTENSIVELY dynoed a slightly modified 502 mpi the past 2 months, the ugly gen V style/mefi 1/ and 2 454/502 by far outflowed ANY upgraded air cleaner on the market. The hardin kn with square to round adapter killed 30-40 hp on a 540 hp 502, even the vortech engineering/AZSM etc giant billet rectangle version did not come close to the stock early one (with 2 dimples in the cover). You have by far the best factory flame arrestor, even a HP500 efi kn element killed 20 hp over the stock one in my testing, fwiw, Smitty

Total piece of hp killing garbage!

Thank you so much for the info!!

How do I open up your attachment?

Not sure, I attached a picture, as a registered user you should be able to open it. Go down a few threads and read my 502 mpi intake on dyno thread, I was completely shocked as to how good the factory flame arrestor worked and how bad the aftermarket ones are, especiually the oval clamp on version. Now the 98 up gen 6/mefi 3 454/502 flat plate flame arrestor killed hp too. I gutted a early one (shown in the pics) and a fully intact one outperformed slightly it on dyno every single pull.

Here's ArcticFriends thread on all of this and more:
http://www.offshoreonly.com/forums/g...n-my-shop.html

Scott, just made pulls last week now that dynos back up, stock 500efi kn robbed 20hp too, hard to believe the big nasty restrictive looking 502 air cleaner kicks its azz!!!

Amaaaazing!!

Maybe we should just use surgical cotton...for....wait...surgery. LOL.

Remember my test on the 9x4 K&N FA on the small block carb mid 300hp years back ? It lost almost 2mph. Same hr, many runs with vs without, back to back...same section of lake.