HELP: Not the power level should have

[70pontlemans]

Need help from all you performance gurus. I recently installed a chevy 400 bored to a 406 and it doesn't seem to have the power it should. It wont even spin the tires. WHAT AM I missing? WHY DON'T i HAVE ANY POWER DOWN LOW? below are the specs.

406 stock bottom end around 9.5 comp ratio
Lunati street master cam 276/286 adv 221/230 @.050 454/454 lift lsa112 RPM Range 1000-5800
Vortec heads
RPM Intake
Street Avenger 670
MSD Billet Dizzy, MSD box, re-curve kit 16deg stop bushng with the lightest springs timing set at 35deg total all in by 2500rpm
th350 shift kit
2000-2200 torque converter
3:73 diff
tires 255/60/15
Car 1978 Cutlass salon 3450lb (about 200 miles since rebuild)
What am I missing, are my expectation to high?

 

[DRIVEN]

That combo should smoke tires all day long. Just out of curiosity, what is the manifold vacuum at idle? If you give it a little more timing does it get better?

 

[70pontlemans]

That combo should smoke tires all day long. Just out of curiosity, what is the manifold vacuum at idle? If you give it a little more timing does it get better?

Around 15psi @750 rpm. Rght now timing is at 18-19 initial, how much more whould i be able to advance it?

 

[DRIVEN]

I was more curious than anything else. That's probably plenty initial timing and that is decent vacuum. Maybe give it a couple more degrees just to see how it acts. I've had a couple engines that liked a lot of initial timing and were lazy without it. You can always limit total later.

 

[565bbchevy]

Street Avenger 670

Is this the vacuum secondary version? If so maybe try dialing in the secondary with different springs for the diaphragm.

 

[64nailhead]

Something's wrong in your tune or cam timing or transmission.

Assuming that your transmission/TC combo are working as they should and whomever assembled the engine verified cam timing. FYI - that's anpretty healthy cam for your compression and TC. At what rpm can you stall to? And when driving in second gear at or around 2200-2500rpm's, where does the rpm jump to when you go to WOT? If it's not 3200+, then your converter needs to be retuned.

You mentioned initial is at 18-19, that is with the vac advance can unhooked and the line plugged correct? And what are the all in rpm and timing?

Edit : forgot to mention, that 670 carb is too small for a 350 or 383 let alone your 406. But it is not your issue until you see 5000 rpm's.

 

[70pontlemans]

Is this the vacuum secondary version? If so maybe try dialing in the secondary with different springs for the diaphragm.

I got the spring kit and installed the lightest second lights springs with only negligible results. I wonder if the 112lsa is effecting the low end,

 

[DRIVEN]

Maybe on a dyno you're giving something up. I'd think a wide angle like that would increase idle vacuum, thus improve carb responsiveness.
Was it just installed "straight up" or was a degree wheel used?

 

[70pontlemans]

Something's wrong in your tune or cam timing or transmission.

Assuming that your transmission/TC combo are working as they should and whomever assembled the engine verified cam timing. FYI - that's anpretty healthy cam for your compression and TC. At what rpm can you stall to? And when driving in second gear at or around 2200-2500rpm's, where does the rpm jump to when you go to WOT? If it's not 3200+, then your converter needs to be retuned.

You mentioned initial is at 18-19, that is with the vac advance can unhooked and the line plugged correct? And what are the all in rpm and timing?

Edit : forgot to mention, that 670 carb is too small for a 350 or 383 let alone your 406. But it is not your issue until you see 5000 rpm's.

The motor was assembled buy a machine shop, so at this point I can only hope it was done correctly. So, do you think the Tq converter needs to have a higher stall. It seems to stall right at 2400 using the break stall method, have not tried the aforementioned method. The Dizzy has no vacuum advance. total is all in @ 2500.

 

[70pontlemans]

Maybe on a dyno you're giving something up. I'd think a wide angle like that would increase idle vacuum, thus improve carb responsiveness.
Was it just installed "straight up" or was a degree wheel used?

It was done at the machine shop, of curse they claim it was installed according to the specs on the cam card.