New Carb
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Joined: Jul 2023
Posts: 4
New Carb
I just recently purchased a 1985 Z28 with 42000 miles. I prefer to keep the car mostly stock, but I need a new carb for it.
The number on the carb is 17085204. My question is should I just go with a rebuild or swap in a Holley? I am more,
interested in low end performance and not high end. I cannot find anywhere what the CFM rating is for the Rochester.
Is it 600? If I go with a Holley any recommendations? According to the CFM calculator tool it recommends a 450 CFM,
based on 305 CI and 6000 max rpm. any advice is appreciated.
The number on the carb is 17085204. My question is should I just go with a rebuild or swap in a Holley? I am more,
interested in low end performance and not high end. I cannot find anywhere what the CFM rating is for the Rochester.
Is it 600? If I go with a Holley any recommendations? According to the CFM calculator tool it recommends a 450 CFM,
based on 305 CI and 6000 max rpm. any advice is appreciated.
Super Moderator
Joined: Jul 2005
Posts: 9,507
From: Okemos, MI
Re: New Carb
Probably not a lot of carb knowledge around here.
What I can tell you is:
Holley carbs have a reputation. There are those who love them, but they tend to be a little tricky if you’re used to something else. I hear really good things about the tunability and ease of maintenance of Edelbrock’s carbs. I don’t know how specifically applicable that is to your engine, so please take with a grain of salt.
Regarding CFM: if you don’t care about high RPM performance, your max CFM is not very important! I would think a 450 would serve you just fine. That said, Wikipedia says that the L69 engine (not 100% sure that’s what you have) had a Rochester Quadra-Jet 750 carb from the factory.
6000 rpm is a lot of RPM for a stock(ish) carb’d SBC, especially since you don’t care about the high RPMs! The factory power peak was at 4800rpm, and this site says redline was 5500.
What I can tell you is:
Holley carbs have a reputation. There are those who love them, but they tend to be a little tricky if you’re used to something else. I hear really good things about the tunability and ease of maintenance of Edelbrock’s carbs. I don’t know how specifically applicable that is to your engine, so please take with a grain of salt.
Regarding CFM: if you don’t care about high RPM performance, your max CFM is not very important! I would think a 450 would serve you just fine. That said, Wikipedia says that the L69 engine (not 100% sure that’s what you have) had a Rochester Quadra-Jet 750 carb from the factory.
6000 rpm is a lot of RPM for a stock(ish) carb’d SBC, especially since you don’t care about the high RPMs! The factory power peak was at 4800rpm, and this site says redline was 5500.
Last edited by JakeRobb; Aug 17, 2023 at 06:51 PM.
Administrator
Joined: Nov 1998
Posts: 71,098
From: Hell was full so they sent me to NJ
Re: New Carb
Unfortunately, this site has very little traffic. Over 100,000 members, and only a handful of posts per day (and 1/2 of them are from spammers). And most of the activity seems to be related to 4th Gens. Hopefully you will get someone with a 3rd Gen to respond.
Another site to consider would be www.thirdgen.org
Another site to consider would be www.thirdgen.org
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