View Full Version : Carb Question?
86FIREBIRD305
02-19-2008, 05:25 PM
i just aquired an old Holley. the list number for it to look it up is -Holley 6210-
is this a good replacement for the old Q-jet on my 305?
if the carb on the car now is original, its an electronic quardajet and is hooked up to a basic type of ecu and works in tune with the distributor
86FIREBIRD305
02-19-2008, 05:32 PM
so does that mean it wont work? if so, how can i fix this?
WildBillyT
02-19-2008, 05:44 PM
Should be a spread bore replacement for a Q-Jet, but if your 305 is stock it may be getting on the high side of "too much carb".
86FIREBIRD305
02-19-2008, 05:48 PM
A 650?
WildBillyT
02-19-2008, 05:54 PM
A 650?
The most popular carb for stock and mild 350 setups is a 600 vacuum secondary Holley. Note I didn't say "It's too much carb" I said it's getting there. You will probably be just fine as long as it's not a 650 double pumper (which it isn't, based on the LIST number).
As smoking said, though, you have an electronic Q-Jet so you will probably have to depricate or abandon your existing electronic engine management stuff.
Somebody who has done the conversion can probably guide you better than I can.
86FIREBIRD305
02-19-2008, 06:10 PM
well its deffinately not a double pumper.
edpontiac91
02-19-2008, 06:43 PM
well its deffinately not a double pumper.
Unless your Q-Jet is WAY out of wack, you're NOT going to see any improvement on a STOCK engine, especially a 305. Make sure(if your looking for more power)to check things like plug wires-spark plugs-fuel filter-distributor cap-timing and more. Any combination of those not working well, will cost you power. It's not like having a BBC with 450 hp, and you lose 10-15 hp, you'll not really going to feel it. But lose 10-15 hp when you only have 145 hp is really going to hurt. :nod:
84HOtransam
02-20-2008, 08:09 AM
I did the swap when i pulled my 305 for a 350...the stock qjet is plenty of carb for the 305..i went 14.3 on it with the L69...once you switch the carb out to non computer control you need a non CC dist. as well..you can also lose the computer and pull the wire harness to....There are a bunch of free mods on third gen.org you can do with the CC qjet..I think i still have my qjet with all of that stuff done on it plus some extra rods and hangers to tune the secondaries...it would be a more efficent improvement then just putting the holley on it..
Pampered-Z
02-20-2008, 08:50 AM
If you engine is stock leave the carb as is. If it's modded you can get different metering rod and such that will help. GM offered a kit years ago to put the ZZ4 engine into 3rdgens and it came with a different ECM and the carb parts. I doubt they still sell it but you can probably find the part numbers, and then get a chip burned.
I had a Compucam emmisions cam and Edelbrock headers in my 84 (305HO) and the stock carb feed it fine with only a few mods. There is a book ( I once had - Justin? ) that about modding Q-jets, some of the simply tricks work wonders!
WildBillyT
02-20-2008, 09:23 AM
If you engine is stock leave the carb as is. If it's modded you can get different metering rod and such that will help. GM offered a kit years ago to put the ZZ4 engine into 3rdgens and it came with a different ECM and the carb parts. I doubt they still sell it but you can probably find the part numbers, and then get a chip burned.
I had a Compucam emmisions cam and Edelbrock headers in my 84 (305HO) and the stock carb feed it fine with only a few mods. There is a book ( I once had - Justin? ) that about modding Q-jets, some of the simply tricks work wonders!
The HPBooks Rochester Carburators book has a bunch of this stuff.
Tru2Chevy
02-20-2008, 09:47 AM
There is a book ( I once had - Justin? ) that about modding Q-jets, some of the simply tricks work wonders!
I thought I gave that back....I'll go check my bookshelf.
- Justin
86FIREBIRD305
02-20-2008, 12:06 PM
then should i sell it? i'll have to rebuild it first.
-Tom
Pampered-Z
02-20-2008, 02:06 PM
I thought I gave that back....I'll go check my bookshelf.
- Justin
Damn kids!
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