I have also just finished my 318 and tranny rebuild, experiencing the same type of issue, at least on 87 octane. At 93, it's much less reduced. I've been focused on vacuum, spark and fuel as these are primary lean causation. Have have found several small leaks in the evap system, yanked the AG out to replace the gaskets causing intake leaks. Idle vacuum is now 14", but I'm still not happy with the engines perf. Checked and re-gapped plugs to .052" (Screamin Demon coil) and Live Wires. Had stock injectors serviced and all 100%, fuel pressure @ 49 steady. I still need to check for fuel volume tho and have bought a snap on mt2500 to thoroughly ts this (and probably other) issue. I re-used the stock rotating assembly, so this issue isn't related to that.

 

The pcm in this truck is the 360 on besides that. Threw that website for a basic pcm which one do I get then? Because this truck is my daily driver and sometimes I do mud for fun.

 

A guy on this forum was running lean with a 360 with a camshaft (.480 lift). He went with 24s and the lean spot vanished.

He needs 24s on a 408. I recommend the FIC blue demon injectors. they are Bosch design III and I would get them if I didn't have the design IIs already.
http://fuelinjectorconnection.com/sh...&productId=191

These are the same body of injectors that come with newer model 2ndgens.

For 169 bucks, I would get them for a 408 in a HEARTBEAT. I am actually pondering getting the 19lb design IIIs (Same price but the yellow ones).

 

ALso, this is probably not the problem, but I thought my engine was pinging when I was at WOT but later found out that my Belt was SHEARING OF one of the pullies and the shears were getting tangled on the fan shaft and banging the fan blades. Sounds EXACTLY like pinging!!!

I now have a 4 rib belt :P Yeah, i know I should get another belt. But i need to address the pulley alignment problem. I just hardly drive my truck enough to have real urgency.

 

Im the owner of that 408 so ur saying the injectors are part of the solution along with the gettting a different pcm?

 

Alright I have come to the conclusion that timing is playing a role in my hard knocking noise. Now I have check the timing chain and it checks out. But the shaft the drives the oil pump my be the problem. The question that I have how do u set that???

 

Use a scanner, and verify fuel sync. If fuel sync is good, dist is in the right spot.

 

I dont have a scanner. And I'm unable to find any info about that shaft.

 

I did have the cpu programmed by bgperformance for the bigger cam and injectors

 

I would be having a chat with BG then..... as timing is controlled purely by the PCM..... there is no knock sensor, PCM just uses tables to alter timing. Moving the distributor only changes when the injectors fire. Has nothing to do with spark.