LS Build: In Progress

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04-05-2019 | 08:23 PM

#201

Rookie

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From: Grand Rapids, MI

Thanks for reporting back!
I thought LS motors liked big splits. I always see 12°-13°, like 235°-248°, especially on carb LS builds. I could be wrong, but I believe that is what I read.

04-05-2019 | 08:31 PM

#202

mggdoors

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From: San Tan Valley AZ

Quote:

Originally Posted by Rookie

I thought LS motors liked big splits. I always see 12°-13°, like 235°-248°, especially on carb LS builds. I could be wrong, but I believe that is what I read.

That is the way alot of guys seem to go. Its great in a drag car that needs traction out of the hole. That big split kills the bottom end and hurts the midrange but helps the top end 6500+ where I will never see. Not to mention big splits create big overlap which I cannot have in marine use. I tend to go against the grain compared to alot of guys doing cams but I have had great results.

04-05-2019 | 09:13 PM

#203

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From: On A Dirt Floor

You do the typical things like make a few runs without the flame arrestor on ? try a known good carb ? make sure proper voltage to box and coil ? Known good coil? etc/etc

You would think a true 1050 carb wouldn't restrict enough to cause 1.2-1.3:Hg" ? or maybe it as the flame arrestor ?

I've seen some unconventional intake vs exhaust cam lobes on a cam do this too. .050" 's where conventional. Probably 6-10 of them.They basically caused a 'sticking a potato in the exhaust' effect. LOL.

Last edited by SB; 04-05-2019 at 09:15 PM.

04-05-2019 | 09:29 PM

#204

mggdoors

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From: San Tan Valley AZ

Quote:

Originally Posted by SB

Ran with and without flame arrestor, verified voltage, verified alt output, did not use known carb although we did run both carbs to verify calubrstion. We seen .1 vac at highest until we went to 2” spacer which produced 1.3”. It sure acts that way. Its either restriction cam doesnt like or cam advanced retarded. Now pardon me while I have a melt down. Cant find my harmonic puller anywhere. Gonna lose my **** today. So close yet so far

Last edited by mggdoors; 04-05-2019 at 09:31 PM.

04-05-2019 | 09:37 PM

#205

mggdoors

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From: San Tan Valley AZ

Thr only other thing im wuestioning is the annular carb. Ive heard of them vaporizing the fuel effectively killing the oxygen in the plenum. Never seen it.

04-05-2019 | 09:38 PM

#206

mggdoors

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From: San Tan Valley AZ

Like my great grandpappy would say “ Im too drunk to taste this chicken”.

04-05-2019 | 09:40 PM

#207

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From: On A Dirt Floor

No, but seen them go rich at higher rpm, zapping power. I did not see/read you had annular. Interesting a 408LS with a 4150 carb needed annular boosters, but what the hell do I know.

04-05-2019 | 10:16 PM

#208

mggdoors

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From: San Tan Valley AZ

Quote:

Originally Posted by SB

No, but seen them go rich at higher rpm, zapping power. I did not see/read you had annular. Interesting a 408LS with a 4150 carb needed annular boosters, but what the hell do I know.

Doesnt need it. Sure the hell helps throttle response with a big cam in a small engine though especially at low rpm.