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Discussion Starter #1
Have a 70 Mach 1 has a 351C 4V with a C6 transmission
Has headers, Edelbrock Torker, mild cam, full MSD ignition system and a 750 Double Pumper. Seems to be way over carburetor'ed
What is your opinion on what should be on the car?
Thanks
 

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I have a 70 393C stroker, FMX, airgap,msd,trickflow,355 in back. full roller 602/612. Currently have a 780 working very well. I would go 680 ss quickfuel vac secondarys.
Thats a lot of carb, most likely not to responsive. Try changing your timing, clevelands love advance. bump your initial incrementally up to around 18 if it wont ping and be all in around 2800 rpm.32 degrees.
 

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Try a vacuum secondary carb with the auto.

As for a 680, it will likely use a 650 carb body. I am running a 670 (650) on my 302 and on the dyno, measuring vacuum, it was not too big with the vacuum secondaries. At least at WOT. Although my car runs great driving around too.

I just read the other day on here that Clevelands want more carb. I can't speak to that and if a 670 (650) is working on a pretty hot 302 I guess it could work on more mild 351c. But if it were me? I'd probably go 750 with vaccum secondaries. At least that's what I'd try first.
 

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That 750 DP is probably a little much and a vacuum secondary carb would probably be better with an automatic transmission.
But if you want to try something cheaper than a new carb get a 1 inch 4-hole spacer and an assortment of jets for tuning.
 

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Do you have an AFR gauge installed so that you will be able to see the air/fuel ratio as you're driving? If not, consider putting the money there first. It is nice being able to see actual ratio numbers.
 

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Discussion Starter #8
Sure is a lot of Carb makers out there these days. Is Holley still one of the best?
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Most likely just needs to be tuned. An early 351C-4V won't be over-carbed with a 750... if anything a well-modified 351C-4V might need a bit more.
 

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65 Fastback 289 4 spd, 65 convertible 5.0L 5 spd. 3.73 8.8
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Most likely just needs to be tuned. An early 351C-4V won't be over-carbed with a 750... if anything a well-modified 351C-4V might need a bit more.Reply
I agree, probably just needs tuned. Have you pulled plugs to look at them
 

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If you're looking to downsize, I have a very low mileage aluminum body Holley 670 Street Avenger on the shelf after my EFI swap that I will part with. You're not that far from me. Shoot me a PM if interested.
749287
 
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