looking for some advice on carb selection
Thread Starter
Racer
Joined: Apr 2008
Posts: 319
Likes: 7
From: Rochester NY
looking for some advice on carb selection
I wanted to get some advice on what carb I should run on my modified 77 vette that I purchased this year.
I'll be doing some small work in the winter - I just purchased an Edelbrock Performer air-gap RPM intake and I'm looking for a carb change - I want more performance - the car is just a cruiser - but I may want to take it to the drag strip for a few runs each year - I'm not worried about gas mileage - so interested in opinions.
What I have in the car now is:
350 bored over .30 and it has a set of Brodix aluminum heads (170cc intake ports, 69cc combustion chambers, 2.02/1.60 valves, 1.25 valve springs.)
Also it has a Lunati cam – 224/224 duration@ .050, .460/.460 lift. Crane 1.5 ratio aluminum roller rockers. TRW forged pistons. Exhaust -Hooker headers through 40 series Flowmasters no cats.
350 auto trans has a B&M Hole shot 2000 stall converter and 3.73 gears.
What do you recommend?
Thanks-
I'll be doing some small work in the winter - I just purchased an Edelbrock Performer air-gap RPM intake and I'm looking for a carb change - I want more performance - the car is just a cruiser - but I may want to take it to the drag strip for a few runs each year - I'm not worried about gas mileage - so interested in opinions.
What I have in the car now is:
350 bored over .30 and it has a set of Brodix aluminum heads (170cc intake ports, 69cc combustion chambers, 2.02/1.60 valves, 1.25 valve springs.)
Also it has a Lunati cam – 224/224 duration@ .050, .460/.460 lift. Crane 1.5 ratio aluminum roller rockers. TRW forged pistons. Exhaust -Hooker headers through 40 series Flowmasters no cats.
350 auto trans has a B&M Hole shot 2000 stall converter and 3.73 gears.
What do you recommend?
Thanks-
Last edited by Vette Cruz-in; Oct 12, 2010 at 09:08 PM. Reason: added more info
Burning Brakes
Joined: May 2008
Posts: 860
Likes: 0
From: Stratford Ontario
I think something in the 750 CFM range would be good for that set up. I like the holley DP,s because there easy to tune. Regardless what carb You put on. You will want to have someone dial it in for You, or learn to to dial it in Yourself.
Thread Starter
Racer
Joined: Apr 2008
Posts: 319
Likes: 7
From: Rochester NY
I would definitely need one to help tune the carb, I've tried in the past and I would need mechanic to help out, I also want to have my transmission shift points looked at and adjusted due to the carb and intake manifold change.
Any other advice? Many people say that the 750 DB would work, but some say that since I have an auto I would need a larger stall converter. I have 3:73 gears so that should help. The holley tech actually suggested that the 670 street avenger would be a better choice... I wonder if he was just thinking about better mileage vs performance?
Any other advice? Many people say that the 750 DB would work, but some say that since I have an auto I would need a larger stall converter. I have 3:73 gears so that should help. The holley tech actually suggested that the 670 street avenger would be a better choice... I wonder if he was just thinking about better mileage vs performance?
Le Mans Master
Joined: Oct 2006
Posts: 7,123
Likes: 433
From: Gladstone MO
C3 of Year Finalist (appearance mods) 2019
A 750 would be a good choice with a couple of things to consider-
Your off the stop performance will be down a bit, because of the lower speed airflow thru the carb at low RPM. That will be offset by the performance above 3000 RPM.
The other thing is that if you use a mechanical secondary carb, there's likely to be a bog or sag in the midrange transition that will be a bear to get rid of. I'd suggest going with a vacuum secondary carb. Those have a better "signal" to the secondaries and open them as the engine demands. Mechanical is controlled by your foot.
Tuning is not as big a thing as you might think- it tales patience and some tools, but it can be done. In general, the Holley and Demon carbs are fairly close right out of the box, just need some tweaks to get to right on. That's where a wideband O2 meter gets handy.
Your off the stop performance will be down a bit, because of the lower speed airflow thru the carb at low RPM. That will be offset by the performance above 3000 RPM.
The other thing is that if you use a mechanical secondary carb, there's likely to be a bog or sag in the midrange transition that will be a bear to get rid of. I'd suggest going with a vacuum secondary carb. Those have a better "signal" to the secondaries and open them as the engine demands. Mechanical is controlled by your foot.
Tuning is not as big a thing as you might think- it tales patience and some tools, but it can be done. In general, the Holley and Demon carbs are fairly close right out of the box, just need some tweaks to get to right on. That's where a wideband O2 meter gets handy.
Heel & Toe
Joined: Jun 2010
Posts: 15
Likes: 0
From: Adelaide South Australia
Drifting
Joined: Aug 2005
Posts: 1,682
Likes: 3
From: League City TX
Holley 650 Street HP. Part # 0-82651
These guys on e-bay have them for $360.99 http://cgi.ebay.com/ebaymotors/ws/eB...#ht_1673wt_939
These guys on e-bay have them for $360.99 http://cgi.ebay.com/ebaymotors/ws/eB...#ht_1673wt_939
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Pro
Joined: Jul 2010
Posts: 532
Likes: 1
From: new york city ny
I have almost the same setup as you (slightly bigger cam).
Holley tech support said that 670 street avenger will fit my setup perfectly. I also asked few tuners/engine builders and they said the same.
S.
Holley tech support said that 670 street avenger will fit my setup perfectly. I also asked few tuners/engine builders and they said the same.
S.
Thread Starter
Racer
Joined: Apr 2008
Posts: 319
Likes: 7
From: Rochester NY
scyzork23- Thanks for the info - the Holley Tech also told me a 670 street avenger is the right choice, but so many people and mechanics are telling me that I should go with a 750 DB..... I guess I can play it safe with a 670, but I just don't want to regret not getting a 750 if that could help out with performance.
Last edited by Vette Cruz-in; Oct 18, 2010 at 07:46 PM.
Pro
Joined: Jul 2010
Posts: 532
Likes: 1
From: new york city ny
Holley 670 will be good until you hit solid 400hp.
If you think that you might be there than use 750.
S.
If you think that you might be there than use 750.
S.
scyzork23- Thanks for the info - the Holley Tech also told me a 670 street avenger is the right choice, but so many people and mechanics are telling me that I should go with a 750 DB..... I guess I can play it safe with a 670, but I just don't want to regret not getting a 750 is that could help out with performance.
