Power Problem Solved UPDATE Pics

My 383 with a DLI blower on it is a pig ,so I upgraded the headers and new SS-exhaust with X-pipe.
As I was going over everything I found I was only getting a little past 1/2 throttle.
So I fixed that and took it out and for the 1st time made a POWER run up the road.
It did run MUCH better

Did is the key word: rolled into it at 40mph in 3rd. was pulling good--BANG !!! Backfired thru carb. started shaking and knocking.
Fuel pressure never dropped below 8-lbs.
Coasted home got it to start,knock comes and goes,idles like it has a dead hole. Oil pressure normal but pulses.
Pulled valvetrain OK.
Next is comp.test.
I assume I took a rod bearing or even a piston.
Odd thing so far is the oil is clean and there was /is no smoke and the oil/crankcase does`nt smell. Normally when I`ve seen bearings burn you can smell it as soon as you get in the motor.
Maybe it pushed a headgasket between cyl.s

Not exactly sure why the POP/knock/ miss order of events yet.

Any feedback/experiences would be welcomed

My guess is it went lean and or detonated because of, to much timing, low fuel quality. First thing to do would be to pull the plugs and see what they look like, then a compression check.
Also I cant see the exact carb but be sure the power valve wasnt damaged from the backfire.

Piston is missing ringland

2

It was making 5lbs of boost. Fuel pressure 8lbs.
Carb is chinese 950 Holley89jets front/96rear.
Using a boost referenced power-valve.
Car is quiet and never heard pinging,but that obviously didnt mean squat
Oh well back to the drawing board.
It had KB- flat-tops and 9.25 cr.
Next time it`ll be 8 to 1 and a blower cam.

Do the plugs have little metal flakes on them? It may have been detonation from timing that did you in.

9.25 and 5 psi isn't to much unless you are maybe running 38* timing. I run 33* at 5 psi 9.1:1 and 91 octane. How was the ring gap? Keithblack hyperutectic? Probably the problem with not enouph ring gap. No need to lower comp unless you want to run more boost.

Looks like detonation damage to me.

Oh- Some people will argue but KB hyperubroke it pistons do NOT work well with boost.

People with the 2.2 turbos avoid them like the plague as they fail under stock boost levels.

Stock cast pistons? 35 pounds of boost baby, 35 pounds.

They work fine but make the ring gap bigger and they are more fragile making them more damage prone when you detonate.

Quote:

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They work fine but make the ring gap bigger and they are more fragile making them more damage prone when you detonate.

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Don't agree with you, and I have built hundreds of turbo motors.

Even the manufacture states they are not good for boost applications, why they sell them for the application is beyond me.

Hell, just read an article in Hot Rod where they built a small block chevy with hyperjunk pistons and at 9 psi with 30 degrees of timing and 100 octane fuel laid waste to 6 pistons. No detonation was noted on the dyno and the ring gaps were set loose.

They fully admitted that they went cheap and should have gone with forged.

I'll replete- Stock cast Chrysler 2.2 pistons will take 35 pounds of boost pass after pass without fail.

Been there and done that.

Hyperutectic is good for stock rebuilds or normally aspirated builds at best.