Heres another thing to keep in mind with using a bored out TB on one of these MPI 502/454 deals, IF you have enough cam and other work to take adbvantage of it, the power band carried past 5600 before starting to drop, with the smaller TB and restrictive FA this happened closer to 5200/5300, carrying rpms gives a boat longer legs without having to prop it so steep its a slug accelerating, FWIW.

Which one of these are you saying is a POS?

The stock gen V FA beat both of them on all 3 TB's, the top one was the real hp killer, the bottom one beat the stock gen6 FA and was pretty close to the genV till we put 68mm tb on. I would have bet money the vortech one on bottom would kick ass

Measuring the hp killing AZSM FA i get a opening of 3.5 x 3", the one in top pic looks bigger, i wonder IF its been re-designed? In next few days im going to do some testing like mentioned of steady state timing mercruiser ign module vs dui w timing tables filled in the same from 3800 up to see IF i can figure out why the dui module loses hp. I will also do a couple pulls w just the adapter for the AZSM w no element to see IF its the adapter killing hp or the element

cool thread I have 2 502 mags that need rebuilding and I would love to just do some small and easy mods to gain a few hp's!!!!

I wonder if the DUI module is changing timing very slightly.

Nothing like standing in frt of a motor with it at full load and rpm. For some reason I always cover my nutz with my hand, because obviously it wouldn't protect anything. LOL.

Any pics of the Vortec base vs the Crockett Base

Oh, and Smitty, I have seen issues from re-oiled K&N's. Just as a heads up in case any are re-oiled.

The vortec base IS the crockett FA, base says vortech on it, cover says crockett on it, it looks VERY UN-restrictive, if i get all ambitious i might machine two aluminum cones as suggested by gimmefuel aimed at the throttle blades and mount them in the cover

Thats what im wondering too, i can fill in timing tables to 36 degrees from 40 to 100 map from 3800 up and just free rev it at 4000 w a setback timing light on it when i test both modules. Theres a final test that will be a whole new thread im going to fo when completely done involving some taylor wires that have a couple measuring in the MILLIONS of ohms im going to swap on that were on my 540 ehen it came up short running na on dyno last time too, i love this stuff!!