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Classifieds => Miscellaneous / Spam => Topic started by: muffbro on October 31, 2013, 04:47:30 PM

Title: ISO carb info
Post by: muffbro on October 31, 2013, 04:47:30 PM
my 15 year old son and I are re- building a 1979
Chevy PU for his first vehicle.  we swapped the old 6 banger for a 305.... 

it needs a carb,  any suggestions.....???


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Title: Re: ISO carb info
Post by: JBASHAM on October 31, 2013, 05:01:05 PM
 Are u in CA? Only reason I ask is for smog issues... Fuel mileage and performance wise , the OE quadrajets were actually pretty good carbs. If not a 600cfm edelbrock would be perfect, I run one on a 305 in my 72 blazer.


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Title: Re: ISO carb info
Post by: ka0tyk on October 31, 2013, 05:30:53 PM
id slap an edelbrock performer 500 on it and be done.  CFM wise on a 305 with a generous 85% VE and a 5k rpm max range puts you under 500. 

plus edelbrocks site says "500 for a small v8 like a 305" it wont cost an arm and a leg either like a holley/demon.

http://www.edelbrock.com/automotive_new/mc/carbs_acc/performer.shtml (http://www.edelbrock.com/automotive_new/mc/carbs_acc/performer.shtml)

Title: Re: ISO carb info
Post by: muffbro on October 31, 2013, 06:40:47 PM
not in California so no smog issues .....  it's not a real hot rod, headers/flow master exhaust....the engine is stock.

I'll
check the on the  Edelbrock.....it's got the QJ on it now, but I have zero knowledge base for that particular carb.....



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Title: Re: ISO carb info
Post by: crewchief22 on November 01, 2013, 06:32:03 AM
I am a fan of the Q-jet carbs.  It's likely going to give you the best cruising mileage and decent performance under full throttle conditions.  A common problem with many of the Rochester carbs was wear in the throttle shaft/bast plate causing vacuum leaks.  If everything feels tight and there aren't  any other issues with the carb you have, I'd suggest having it rebuilt by a qualified shop or look into the new ones available from Edelbrock.

Title: Re: ISO carb info
Post by: muffbro on November 01, 2013, 07:06:02 AM
after looking at  pricing on the edlebrock my son has decided the re- build  option on the QJ is looking better and better ( though not as shiny and pretty)
he's gonna pull it this weekend and take it to a local engine wizard and let him decide if it's rebuildable.... if not, we'll be looking for another QJ to replace it.

thanks guys!!!!






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Title: Re: ISO carb info
Post by: HardLuck Baker on November 01, 2013, 06:13:23 PM
I have a edelbrock 750 with electric choke I need to get rid of.


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Title: Re: ISO carb info
Post by: muffbro on November 01, 2013, 06:40:01 PM

I have a edelbrock 750 with electric choke I need to get rid of.


RoB~SoCalJetBoats~

I appreciate the offer, but a 750 is too much for for the 305.....


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Title: Re: ISO carb info
Post by: HardLuck Baker on November 01, 2013, 07:08:06 PM

I appreciate the offer, but a 750 is too much for for the 305.....


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. No problem.


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Title: Re: ISO carb info
Post by: Nobody077 on November 01, 2013, 10:20:54 PM
500cfm will be great for a 302 any more and you will over carb bad, since you said it has a QJ I say keep it. If you were running a 2bbl intake I would suggest a 500cfm Holley , my old 318 dodge truck with headers and cam liked the 2bbl Holley combo over a edelbrock torquer and QJ combo. I did have a np435 with the granny 6.69:1 1st and a 4.11 posi rear so truck loved 1000-3000rpm range.
Title: Re: ISO carb info
Post by: GT Jets on November 01, 2013, 11:32:19 PM
Damn...

I just sold a 600 cfm TBI system that would have been the bomb diggity.

I would totally keep the Q-jet. You can squeak some silly mileage out of one of those with a little knowhow.

Under the carb top near the rear there is a really small spring with an adjustment screw that controls ths secondary air door, this has a spec and should be adjusted before putting on the truck. If you adjust it a tiny but tight than the instructions tell you, it will hold out the secondaries a little longer than normal. I drove a 1976 LS7 powered 3/4 ton 4x4, lifted with 38" Swampers back and fourth from Gilroy to Sacramento for almost 5 months for a job. The stupid thing thought it was a Toyota. I got 18mpg out of it.

GT

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Title: Re: ISO carb info
Post by: muffbro on November 02, 2013, 12:05:59 AM
it's an old forest dept Trk .... 4 spd floor model with the the granny low. .....we are pulling the old rear end  gears and have a locker' with taller gears than what's in it now to help the mileage,
than coupled with a carb update/rebuild I'm hoping for much lower rpm/ higher mpg.... if I can't get it with that, a tranny swap will
be next....


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