I have an edelbrock on my semi built 390 and I've been thinking of switching to a Holley, Idk if the PO put in a really strong spring on the secondaries but I really have to hammer it wide open for them to crack loose. Then when the do it feels like you hit nitrous lol, if I roll into it they won't open. Plugs look perfect but it doesn't feel right, I've always used holleys so I'm lost with this wanabe Carter.

 

I just installed one of those summit 600cfm carbs a few days ago and tuned it today. I had an edelbrock 1406 600cfm on there before, and all I can say is wow, what a difference the summit carb made. Better low end, pulls hard and was easy to tune. I'd suggest one of these over the edelbrocks after this experience. Engine is a stock 390 btw with the carb, holley intake, and headers.

 

What do you recommend for drag racing for a ford 390 600 cfm holley or 750 cfm holley?

 

Depends on what all is put in/on the engine.

 

I have a Holley 650 on a medium 390 build. She runs just fine on the primaries, and roars when nailed. As one of the other posters mentioned definitely get the auto kick down. Good luck whatever you decide.

 

I have good luck with Motorcraft 4300 series 4 barrel carb....the ones that fit say a 73 to 74 Lincoln are rated 600 cfm.....I have a 74 F 100 360, automatic and put 390 intake and this carb on in 1978...most of stock linkage..passing gear and choke etc fit....it really made the 360 run great!

 

As RapidRuss said;

The Holley 600 would be about ideal for your application.

Although a modified Holley 850cfm works good for my FE.
9.72 @ 136 mph

 

i've had three holleys on my 390 since i built it
600 double pumper
650
750 dual feed
engine likes the 750 the best , i put a quick fuel adjustable secondary kit on it so i could keep the secondaries from opening to soon

 

Thread Revival:

Rusty, did you get this intake installed and how is it working out for you?

 

+1
Old thread revival time!
Trying to decide between the Holley 570 and 600, curious how that 570 is doing?

 

Oh man, I completely forgot about this thread! As it turned out, neither the Offy intake or the 570 Holley worked out very well. The Offy was badly warped, and by the time it was cut enough to be flat, it was too narrow for the motor. Had quite a time trying to seal it, finally gave up and bought a brand new Edelbrock Performer. Maybe it would have worked with doubled gaskets, I dunno.

This particular 570 turned out to be a bad one, I pulled it apart and it had a couple metal shavings from the machining process plugging up one of the transfer slots. I cleaned it out, but it never ran right even after that.

The engine they were on isn't in the truck any more either, it sprang a coolant leak into the oil. After all it's other issues I said enough's enough and pulled it out. It's been sitting in the garage ever since.

Now I've got a Holley 600 (the old 1850SA) that I love, great carb. Good power, no issues with it at all. It responds to tuning very well! Beats the living daylights out of the 570 in every way, including purchase price!

The Edelbrock Performer 390 and a Holley 600 (make sure you get the adjustable float version) is a great combo.

Sam

 

Thanks for the input! I was leaning towards the 600 but I think you've helped fully convince me that's the way to go. I have a 670 right now and it works well but I want better torque and hopefully better than 10mpg too.

 

If the 670 is in good shape, I don't see any big issues with running it. A buddy of mine has one on his 460 and it does pretty well. Have you spent much time fine tuning it? Maybe keep the 670 and put the money towards a wideband O2 sensor?

Just some ideas,

Sam

 

Mike I doubt swapping the carb is going to do anything for either of those conditions.



John

 

I have a buddy who is going to give me a Holley 600cfm he has laying around to see how it does. Better fuel economy is prob just a pipe dream with these trucks but I feel I can get better low end performance by downsizing the carb. I live at 6,000 feet where vehicles seem sensitive to oversized carbs. Won't hurt to try since the carb is free. I'll let you know if it makes a difference after I get it dialed in. I'm interested to see if 70cfm changes anything.