big block help!
Thread Starter
Teching In
Joined: Apr 2008
Posts: 7
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From: Tx.
big block help! i just put in a built 454 big block into my pickup. it is mostly stock but fully rebuilt..bored .30 over and an rv cam. but when u put your foot into it it is very sluggish. it has a 600 cfm carb..could this be the problem? is the carb too small? it has a full msd ignition on it also. Anything that can help? Thanx.
6 & 8 Second Club
Joined: Aug 2006
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From: Illinois, RT 66 dragway area
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On mild BBC like that, I believe the smallest carb I ever used was a 700. Is it a short blaa or delay then takes off ok.
Squirter may be set up for a 327-350". Good luck.
.
On mild BBC like that, I believe the smallest carb I ever used was a 700. Is it a short blaa or delay then takes off ok.
Squirter may be set up for a 327-350". Good luck.
.
Thread Starter
Teching In
Joined: Apr 2008
Posts: 7
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From: Tx.
its actually sluggish all the way thru..when u put ur foot in it around a turn it kinda bogs down and sputters and backfires a bit. and when ur sitting still if u hit the gas the stll kicks up but when it kicks in it gets a horrible take off..no acceleration whatsoever
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Do you know what the timing is, both initial and advanced? Thats the first thing to straighten out. Then its on to tuning the carb. First start with a larger one.
Carbs are just as hard if not harder to tune correctly than a computer. Its the right combination of main jets, squirter size, pump size, power valve, and then the emulsion wells need to be working properly. And then you've got the secondary spring rate if you're running a vacuum secondary.
Get a good NEW carb from someone like AED, or BG, or some other reputable carb shop.
Carbs are just as hard if not harder to tune correctly than a computer. Its the right combination of main jets, squirter size, pump size, power valve, and then the emulsion wells need to be working properly. And then you've got the secondary spring rate if you're running a vacuum secondary.
Get a good NEW carb from someone like AED, or BG, or some other reputable carb shop.
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Teching In
Joined: Apr 2008
Posts: 7
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From: Tx.
this was another question i was going to ask about. the timing? i never really ran a time light on it..i just got it to 0..on compression..and set up the distributor. also..could it need hotter plugs? because when u shut it off to quickly it does the compression knocking. and its mostly sluggish..through out the entire powerband.
TECH Enthusiast
Joined: Sep 2006
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From: FLORIDA
Do you know what the timing is, both initial and advanced? Thats the first thing to straighten out. Then its on to tuning the carb. First start with a larger one.
Carbs are just as hard if not harder to tune correctly than a computer. Its the right combination of main jets, squirter size, pump size, power valve, and then the emulsion wells need to be working properly. And then you've got the secondary spring rate if you're running a vacuum secondary.
Get a good NEW carb from someone like AED, or BG, or some other reputable carb shop.
Carbs are just as hard if not harder to tune correctly than a computer. Its the right combination of main jets, squirter size, pump size, power valve, and then the emulsion wells need to be working properly. And then you've got the secondary spring rate if you're running a vacuum secondary.
Get a good NEW carb from someone like AED, or BG, or some other reputable carb shop.
Thread Starter
Teching In
Joined: Apr 2008
Posts: 7
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From: Tx.
yea..im about to bring it in the garage and get to work..i may replace the intake also. and need to find a bigger carb. the biggest i got around the garage is a 650 cfm. about how much wuld a 750 street dominator run me?
11 Second Club
Joined: Oct 2007
Posts: 429
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From: Columbus, OH
a 650 would work, but i would also look at your timing, and also check valve springs, rolller rockers to make sure everything is up to par.. fairly new motor?? Check cam as well- might have knocked out 5 or 7..
OK very 1st thing that carb is WAY to small for a 454 inch engine unless you never see 5000rpm, 2nd you need to put a light on it ASAP! Assuming you have and HEI? I would set the inital timing in the 12*-14* range and set total at around 34*-36*@3000rpm you will need a timing light with an advance **** or a digital version $30-250 depending on what you want. The carb needs to be at least a 700cfm and NO Edelbrock/Carter GARBAGE will work, even installing one a Chevy engine is sacreligious! Buy a 3310 750 Vacuum secondary Holley or a Street Avenger version, either one will serve you well and end all your carb worries. Dont listen to anyone trying to get to run a double pumper on an engine this mild as it will only chew up more fuel and its doubtful it would pay any real power dividends.....
This should be the answer to your issues, unless you have problems elswhere......
If you have any specific questions you can shoot me a PM and I'll be glad to help any way I can
This should be the answer to your issues, unless you have problems elswhere......
If you have any specific questions you can shoot me a PM and I'll be glad to help any way I can
