I Need help 410 Stroker timing Carb Education
I installed cam retarded to idle better, less power/torque to aid traction when launching, and move hp curve up
Currently 60' 1.70 sec
Well then, you got the wrong cam. or too much compression for it.
Here's why;
IIRC that cam is 274/280/110
If it is,
Then in at 116, your durations are;
274/107/116/280/57/ Ica of 73*, (Intake/Comp/power/exhaust/overlap.)
And so, your
Effective overlap is 42* down from 57*, which is a loss of 15*, and the equivalent to between 3 and 4 cam sizes, so no wonder she's down on power.
Your compression degrees are just 107, down from say 115, so more power lost right there.
The exhaust valve is not opening until 116*ATDC on the Powerstroke, ridiculously late. and not closing until 36* ATDC, now on the Intake stroke; So your chambers probably never really finish scavenging, leaving lots of exhaust gasses still inside, ready to pollute the intake charge So when the intake finally opens at just 21* The exhaust scavenging is out of time and reduced to near zero effectiveness. So the Piston is forced into pulling the plenum mixture in, all by itself.
With an Ica of 73*, the Wallace predicts your cylinder pressure to be 150 measly psi, down from 162 when installed at 109.
Whereas
In at 109 the durations are;
274/114/109/280/57/Ica of 66* and Effective overlap of 56*/Badaboom; nowyurtalking
There's way better ways to soften the low-rpm hit; and
way better ways to smooth out the idle;
than retarding the cam.
Start by retiming the cam to 109, then work on the timing.
To smooth the idle, first get the Transfer slots synced up, which may require Bypass-Air, then retard the timing.
Try 14* Idle-timing, 34* Power-Timing, and slow the rate of advance. With cylinder pressure over 160, you will need to run best gas at WOT, and probably delay the all-in to after 3400. If your 60ft takes a dump, fix the traction issues. Not spinning?/ get a higher stall TC.
If you get into detonation issues, you have some options;
1) reduce your cylinder pressure,
2) get a bigger cam
3) anti-detonation injection.
4) Alloy heads
IMO
The 670 may not be optimum, but until the tires stop spinning, it is still bigger than it needs to be. It's a good size for a streeter. And on the Torquer intake, it's probably just right. Once you get the cam timing back to normal, and the ignition timing sorted, you'll see that 670 come alive; right now, the plenum is severely messed up at rpm.
In at 109 the durations are;
274/114/109/280/57/Ica of 66* and Effective overlap of 56*/Badaboom
