4.3L V6 Questions - Team Camaro Tech
Troubleshooting Diagnosing problems done here.

 
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post #1 of 9 (permalink) Old Oct 20th, 01, 01:57 AM Thread Starter
 
Join Date: Oct 2001
Location: Platte City
Posts: 4
Question

I bought a nice little 76 w/an unknown year 4.3L V6 bored and stroked to an alleged 350 cubes. It seems to have very high compression and runs good at Idle. I have a 1406 Edelbrock carb & performer Hi-Rise and homemade headers. It has super power from 0 to 10% throttle, but after that it hesitates and bogs real bad, I did notice some back blast thru the carb, but the headers are welded to the pipes, and I hate to pop them at the heads (if it's a restriction problem)
Fuel Pump reads 5 lbs & 20 gph. Fuel Filter seems clean. My ? is what is the factory timimg on a 4.3L. Also any other advice as I am getting stumped...
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post #2 of 9 (permalink) Old Oct 20th, 01, 02:45 PM
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Bill
 
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350 cubes.....keep dreaming.

------------------
Bill Koustenis
Owner
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Waldorf Md
1971 Chevelle "Heavy Chevy" original owner
1973 Z-28 ..one family car...Brother bought it new in 73
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post #3 of 9 (permalink) Old Oct 20th, 01, 06:23 PM Thread Starter
 
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<BLOCKQUOTE>quote:</font><HR>Originally posted by BillK:
350 cubes.....keep dreaming.

<HR></BLOCKQUOTE>

Nice reply, It really helped alot... Makes me wish I had a mopar.

I said alleged, thats what the chevy lovin dork told me that I bought it from. I dont feel like ripping the motor apart to see how far stroked it is. Anyway I thank you for your fine help. If they would've put a 318 in it I could pull a spark plug wire and whip any small block chevy you drive geek.

Stardust - Ford Electrician
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post #4 of 9 (permalink) Old Oct 20th, 01, 07:11 PM
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Location: skiatook, ok
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Your going to be real popular here with an attitude like that.




------------------
375hp 78 Chevy truck
77 Chevy Nova
95 Chevy Lumina 3.4L
and building a 78 Nova
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post #5 of 9 (permalink) Old Oct 21st, 01, 02:15 PM
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maybe the guy you bought it from meant that the 4.3 is just a 350 missing a couple of the middle cylinders..and, as for your response to BillK- there tends to be a lot of sarcasm around here, and you need to roll with it. if you get defensive and otherwise overreact everytime someone says something you think is a personal attack, you will get ridden by a lot of guys- and ridden hard. you need to remember this is a camaro site-which is(was) built by chevrolet, so if you say stuff like"my 318 will beat your 350 with one spark plug wire disconnected", people might not want to help you out.this is the single best place on the net for automotive help, or just to shoot the breeze.but if you have an attitude, you aint welcome here, and will be put in your place.
as for your problem, i'd say to put the timing at about 10 degrees advanced, turn the idle screws 1.5 turns out, and start tuning. i would also look for vacuum leaks and simple things like that.if you need more help, feel free to ask the people here, but don't have an attitude.i can't stress that enough. we are here to help, and thrive on helping others, even mopar guys.

------------------
1971 Nova(looks like 69 camaro from underneath!)
355sb, vortec heads, HOT cam,T-10 tranny, 3.70 gears 16" IROC wheels
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post #6 of 9 (permalink) Old Oct 21st, 01, 03:06 PM Thread Starter
 
Join Date: Oct 2001
Location: Platte City
Posts: 4
Unhappy

With the greatest humility I beg forgiveness

It just torqued my shorts I guess. I thought
I had a fairly good question and it disappointed me immensly. I dont have a Mopar anyway... I haven't had a "hot
rod" since 1979. There was great rivalry in my HS days of 1975. That was one of my old lines.. (sheepish grin)

I am leaning toward to much restriction in the exhaust as the timing is at 8-10 degrees I disconnected the secondary's and it seems to run alot better.

Again I dont wanna be an jerk, it just happens sometimes... I type faster then I think...

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post #7 of 9 (permalink) Old Oct 21st, 01, 03:18 PM
 
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[This message has been edited by the mechanic (edited 10-21-2001).]
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post #8 of 9 (permalink) Old Oct 21st, 01, 03:54 PM
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Smile

Good call on dropping the attitude...I think you will find that this is the most helpful site on the net...if you can play nice.

Your 4.3 V-6 isnt bored and stroked to a 350...it isnt possible. It would really help if you knew what was in the engine. If it really does have high compression, you might be suffering from a weak plug or plug wire. Timing could be off. Could be insufficient fuel supply. If you have headers on the car, I assume you also have dual exhaust also. If thats the case, then I highly doubt that you have enough exhaust restriction to cause popping back thru the carb. If it is a single exaust running thru a stock catalytic convertor, then a plugged convertor is very possible. If it isnt the exhaust, then it could be a lean transition from cruise to power mode in the edelbrock carb. That can be cured by using a lighter step up spring, and possibly slightly fatter jetting.

Just fyi, most any muffler shop can do a back pressure test and see if your exhaust is plugged...around here it runs about $25.

------------------
375hp 78 Chevy truck
77 Chevy Nova
95 Chevy Lumina 3.4L
and building a 78 Nova
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post #9 of 9 (permalink) Old Oct 22nd, 01, 10:35 PM Thread Starter
 
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<BLOCKQUOTE>quote:</font><HR>Originally posted by travis:
If you have headers on the car, I assume you also have dual exhaust also. then it could be a lean transition from cruise to power mode in the edelbrock carb. That can be cured by using a lighter step up spring, and possibly slightly fatter jetting.

Just fyi, most any muffler shop can do a back pressure test and see if your exhaust is plugged...around here it runs about $25.
<HR></BLOCKQUOTE>
Cool I will get one done, the only thing about the headers is that they are homemade and have some weird 45-55 degree non curved bends right off the block, and yes it does have dual exhaust w/ micro thrush mufflers.
I have been bidding on a pull style fuel pump w/filter on Ebay, but if I have to I will just buy one I like that holley electric. I have this little tiny electric one now, but 20 gals ber hour is like 3 mpg at 60 mph... So I was hoping that was enough, but maybe not when romping it...Anyway thanx again
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