70bigblockdodge
Well-Known Member
I have a 400 in my car currently with some milled and ported 516 heads old aluminum Wiend intake and some generic headers. Runs reasonably well under normal driving. Problem is if I slow to turn from one road to another or someone slows to turn off when I step back in the throttle 1/3-1/2 throttle running on the primaries once the accelerator pump shot burns off the car goes very lean, runs flat like filter is clogged (it is not). I have played around with main jets with little effect slightly better with 78s over the original 72s. When secondaries come on car runs like a scalded cat. Everything points to power valve not opening but it is new this spring along with a good cleaning and new gaskets (Holley kit). It never seemed to do this on the 383, and the 400 is not much different has a 284/484 Mopar cam in it. It has basically done this the whole time it has been on the 400 about a year, before and after the rebuild. Has anyone ever ran into this problem I know it's probably something simple that I'm overlooking, this is killing my 330- 1/8 mi time and I am still pulling 98-99 mph. Looking for some things to check, second set of eyes. Thanks in advance.
Btw it is a dual feed 3310 list Holley from waaaay back.
Btw it is a dual feed 3310 list Holley from waaaay back.