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Old 06-30-2013, 10:32 PM
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sbc problems :(

I have a 305 in my 1983 c10 and I put a larger cam in it and when I go wot I can hear a bit of a back fire what could this be????? 'I was thinking maybe the timing is to much advance? I know that my tuck has a hei distributor but I don't know if I should have it hooked to manifold vacuum or timed vacuum?
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Old 06-30-2013, 10:59 PM
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Quote:
Originally Posted by gavinjames View Post
I have a 305 in my 1983 c10 and I put a larger cam in it and when I go wot I can hear a bit of a back fire what could this be????? 'I was thinking maybe the timing is to much advance? I know that my tuck has a hei distributor but I don't know if I should have it hooked to manifold vacuum or timed vacuum?
Well, either you got some or all of the valves too tight or the cam is beginning to go away or you have two plug wires close together and passing current to one another at the wrong time or........
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Old 06-30-2013, 10:59 PM
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need more info please,cam specs and tune up specs
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Old 07-01-2013, 12:55 AM
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Quote:
Originally Posted by gavinjames View Post
I have a 305 in my 1983 c10 and I put a larger cam in it and when I go wot I can hear a bit of a back fire what could this be????? 'I was thinking maybe the timing is to much advance? I know that my tuck has a hei distributor but I don't know if I should have it hooked to manifold vacuum or timed vacuum?
Is the backfire coming through the intake or exhaust? If its through the intake (carb) then could be retarded ignition timing.
Like others said more info , larger cam = ???, Etc.


Duke
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Old 07-01-2013, 05:08 PM
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the cam specs are 224 224 466 466 and I have it set at 19degres and 10 in the vacuum advance. how di you tell if it throught the intake or the exhaust. and I have a 1406 edelbrock and I think it needs to be leaned out.
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Old 07-01-2013, 08:57 PM
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if its 19 total timing at 3,000 rpm,then you need more.go to 32 total timing at 3,000 rpm with vacuum advance disconnected
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Old 07-01-2013, 11:45 PM
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Originally Posted by gavinjames View Post
the cam specs are 224 224 466 466 and I have it set at 19degres and 10 in the vacuum advance. how di you tell if it throught the intake or the exhaust. and I have a 1406 edelbrock and I think it needs to be leaned out.
You have to take notice where the backfire is coming from. It should be obvious. You prolly got a black char mark on the underside of our air cleaner lid if its coming from the intake side, that's my hunch. If its exhaust, man, it be LOUD , I think you'd know about it!

19deg?? Is that static or total?



Duke
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Old 07-02-2013, 10:41 PM
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im not sure what u mean by static or total? but I have it set at 19 then the vacuum advance set to give another 10 degrees. my buddy set it for me so im not positive im new to this stuff. u want me to unplug the vacuum advance and run just 32 degrees at 3000rpm??
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Old 07-03-2013, 10:35 AM
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Quote:
Originally Posted by gavinjames View Post
I have a 305 in my 1983 c10 and I put a larger cam in it and when I go wot I can hear a bit of a back fire what could this be????? 'I was thinking maybe the timing is to much advance? I know that my tuck has a hei distributor but I don't know if I should have it hooked to manifold vacuum or timed vacuum?
If this only happens at WOT it's probably the carb leaning out on the top end. To go further I'd need to know what carb is on the engine.

Bogie
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Old 07-03-2013, 11:40 AM
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Originally Posted by gavinjames View Post
im not sure what u mean by static or total? but I have it set at 19 then the vacuum advance set to give another 10 degrees. my buddy set it for me so im not positive im new to this stuff. u want me to unplug the vacuum advance and run just 32 degrees at 3000rpm??
Sorry, by 'static' I mean initial . As opposed to 'total'.



Duke
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Old 07-03-2013, 12:50 PM
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its a edelbrock 1406 its not just at wot its also when im just accelerating
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