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Boosted engines need stronger springs then what the cam calls for.

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may not have the right cam for boosted engines...also depends on the amount of boost..

boosted engines love ignition ..
I have my initial at 18* and all in at 3,000rpm @ 36*..you can bump that up a few...good race gas realy makes them come alive.(I know, no brainer)

need to check your carb, blowers need the gas to keep them cool..I run mine on the rich side..92's on the secondaries and 90's on the primaries..

so what if its a SB Chevy...its still an engine ..

where I got most of my info for base line was from Gary Dyer...

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"boosted engines love ignition"


Jeff, this motor may need less, I'm almost sure of it. My 06 GT running 7 psi is down around 17 degrees at full boost, runs like a scalded cat!
It surely wouldn't hurt to reduce plug gap to .025, back timing down to 28, and see what happens.

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it doesn't hurt to try....wouldn't compression come into play along with cam timing and fuel...

I guess I'm too old school..LOL

I only know what works for me...

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"boosted engines love ignition"


Jeff, this motor may need less, I'm almost sure of it. My 06 GT running 7 psi is down around 17 degrees at full boost, runs like a scalded cat!
It surely wouldn't hurt to reduce plug gap to .025, back timing down to 28, and see what happens.

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Its not uncommon for boost to blow out the spark at higher rpms because of a wide gap. Have you done a compression check? What r the cam specs? Also a great Idea to have a wideband 02 on it. Guessing if your rich or lean will get old quick.

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Thanks for the input. Yeah the igniton is a possibility too.

Resistance to RPM is puzzling,I should have a hard time keeping up with it.
Pulls hard at the hit then flat-lines.

It makes 5-lbs boost.

The best it ever ran was its first day out at the Mopar Nats.
I had cooling issues and was leaving the line at 180ish.
jetting was 82/88 {78/88std} only the mech. pump and only 4-lbs. fuel pressure.
It ran [Email]12.22@111[/Email] with poor traction in hotter weather --80`s.
Last 2 times out it was maybe 70,and last night it was 55*.
Cooling has been sorted out and added fuel-pump and jetting since it rattled the valves on the last pass the 2nd time out.
Ran it ALOT on the street and all was well.
Looking back,it actually seems like its too cold???
Maybe I`m way rich yet?
Not sure what thats telling me,,,,yet?

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What needle and seats are you running... a .110 is
in a stock holley... I would go up on them... .120 or .130
any boosted engine I've worked on wanted less timing
as boost/pressure went up

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It has .120 seats in it now.

I can only assume the colder dense air is causing detonation?
The car is REALLY quiet and I can`t hear anything.

But added timing improved MPH, how am I to interpret that?
Even more early and less as it builds boost?

The richer jetted runs gave the best 60.ft times. So it wants more squirter/volume.
110.87 is actually decent at Quaker,it goes uphill. That would be like 113 or so at Norwalk.
Leaves good 1.68 -60ft. leaving at idle,tries to finish good. Sluggish in middle.
The carb is a "chinese" knock-off proform I bought from CRT at a swapmeet.
I wish I could throw on a "good" carb to form a baseline comparison..

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Squirter are usually the 60' so it wants more fuel
on the launch and might need less down track(jets)
EDIT
Also if you are leaving at no boost the engine is
still a N/A engine at that point so it would like
like the timing but as boost starts you need to pull
timing(need a boost/timing controller)

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whats the static compression..

I think ..this is my opinion...you don't have the right cam to effectively use boost...

there I said it...

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whats the static compression..

I think ..this is my opinion...you don't have the right cam to effectively use boost...

there I said it...

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Cam is Summit #-6401 .465/.488 lift,224/234@.050/282/292 adv. 114-c/l.This cam was recommended by several users,and was 62-bucks.
Installed at 109-straight-up. Springs are MP "510" springs
Compression is 8.69,heads pocket-ported "250" iron heads{same as 906`s}
Stock 68` rotating assembly in 66` block.
carb is 850,proform copy. Came with 78/84 jets.
boost referenced power-valve.
1-7/8th headers,2-1/2 exhaust with X-pipe.
Stock conv.3.55 rear.est. weight 3,700 something w/driver.

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Hate to tell you this but MP are JUNK... I ran a set
the first year I built my car... they said good for
.640.... well after the engine didnt work like I
figured I checked the pressures on the springs...
I was in valve float as soon as I left the line...
and the springs measured #65 on seat... so did the
new springs (same ones).... you better check the
spring pressure
Also you have the cam in 5* advanced(which is fine)

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"You also have the cam in 5* advanced...which is fine".

Cam card said 109* ATDC-intake,so thats where I put it.
Where did I figure wrong.

After thinking over all the input, I am leaning towards the ignition. Better air and more fuel taxes the ignition more.
Valve springs would`nt care about the weather,only RPM.
I have a chrome-box,don`t they wire different than the orange?
Going to check all the voltages at the the coil,resistor etc.... too.

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If it was straight up it would be at 114 but you
did what the cam card suggested for which is fine

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Your fuel system won't work like you have it.

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"boosted engines love ignition"


Jeff, this motor may need less, I'm almost sure of it. My 06 GT running 7 psi is down around 17 degrees at full boost, runs like a scalded cat!
It surely wouldn't hurt to reduce plug gap to .025, back timing down to 28, and see what happens.

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it doesn't hurt to try....wouldn't compression come into play along with cam timing and fuel...

I guess I'm too old school..LOL

I only know what works for me...

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