[cobra351w]

Hi,

I thought i'd let you all know of my woes with a Edelbrock Performer 600CFM on my 351W in my Sumo Mk3.

Basically no matter what jetting/needle combination I tried , it would not get past a huge bog at WOT when the secondaries cut in, about 3500rpm in any gear!!

I bought an Innnovate technologies Fuel/Air ratio meter,so I could see what was going on in the headers, this indicated the mixture going from very rich to a very lean, back to a very rich condition through the transient phase

Idle and cruise I could get perfect mixture,

I must have tried every spring /needle/jet combo, ensuring that I did minimal change at a time, still could not crack it.

After several weeks I gave up, looking at other possible causes such as ignition timing/valve timing & vacuum leaks ...all made no diiference or was set correctly.

So I bit the bullet, bought a Holley Street Avenger, standard jetting.

Now this may sound odd, but the engine note sounded completely different at tickover, louder and sharper, on first run out, the engine just took off all the way to 5000rpm, admittedly not perfect, a few flat spots, the mixture was lean throughout, so I upped the main from 65 to 68, and the secondary from 68 to 72...plus changed the vacuum diaphram spring for a lighter one.........now it just frightens me!!


Anybody wanna buy a used Edelbrock 600, I have a complete set of jets as well.!!