Look, Run what you like. If you like 600VS carbs RUN IT! I ran those and don't care for them. I slapped a 750DP on it and was happy with it. And Holley said it wont work. It did! My Truck weighed in @5,400lbs. Work just fine. I even hauled heavy loads with it. And no I didn't jab it to the floor. I know how to drive DP's. JMO.

It is just like "The Poor Mans 427"......That wont work. Watch me! I'm a DP guy and you don't have to wind one 6,500rpms to get power out of it! Remember its just my opinion and nothing more.......Even he likes DP's

 

It might work, but not right and not giving you the best preformance from your engine. You are the kind of guy I used to street race for money to finance my race cars and boats.

 

You would have a tough one on your hands and that wouldn't be my first rodeo. I'm a little more wiser then what one would think! A soon as "The Poor Mans 427" is in the stang.....You could find out and see for yourself and by the way I race for pride and don't need your money to finance my junk.........

As for "MY 390" sounds like he will drive this thing floored no matter where he goes! Re read the post.

 

Ford428CJ, I hear you loud a clear. You're saying "Don't confuse me with the facts, I already made up my mind!" So, go live in blissful ignorance.

 

That was yesterday! And please don't put words in my mouth. Thank You!

 

So you are saying you've changed your ways since yesterday? I doubt. FYI I was racing 428CJs, then known as the poor man's 427, before you were born.

 

I quote "YOUR" from a post below "The 3X2 setup were unbelievable on 390s and 428s. That would be 3 350 CFM Holleys." Thats a little more then a 750.

Look I'm not here to argue about this anymore. I'm done betting a dead horse. I'm just saying what work for me. I'm sure people have different experiences on this type of stuff and what worked for there driving style. So no hard feelings and let bygones be bygones. Take care......

 

Your statement show that you nothing about carbs and multiple carbs. Let me give you carb rule number 1, "a lot of little holes works better than a couple of big holes". Second, "2 barrel carbs are rated a 3" of vacuum while 4 barrels are rated at 1 1/2"." That means when you use multiple 2 barrel carbs, they get rated differently. The 3 X 350 CFM carbs Ford used on the 390 were rated at 860 CFM. Notice that the rating does not give you the 1050 CFM that the 2 barrel rating does. I even attend a Holley tech school back in the dark ages. You need to acquire a carb how to book and start learning. FYI, You never hurt my feelings.

 

I believe a Bear's skin is rather thick almost bullet proof.
Be cool as we have a cool moderator that lets us run off center
at times me included but knowing we will self center again without
getting spanked.

 

Them boys got a little excited, didn't they!!!!

 

putt, good to hear your back into this forum a little more for a while I was thinking they canned you thru some sardine processing plant up north and shipped yo butt to China. Take care bro.

 

The carb discussion has always interested me. I'm a bit torn on the size issue as to me the engine is only going to pull what it's going to pull. It seems to me that you can size the jets properly whether it be a 600 or a 750. I listened to everyone on this forum on carbs when I built my 390...I ended up trying 4 different carbs because I was so **** about trying to get the best performance. I tried 2 different holleys....a 600 and a 750....the 750 was professionally built and modified so I was told....both of the holley's were vacuum secondaries. Then I tried an edelbrock 600 and an edelbrock 750. 3 of the 4 were brand new and I played with tuning all of them. I ended up disliking the holleys as I could never get the secondaries to pull in like I wanted...I liked the edelbrock 750 the best....I'm kinda old school anyway....I prefer a mechanical secondary, I rather like having control of it through the gas pedal, and bigger is better...LOL....all that being said...if they were all set up correctly for the engine I doubt that most people would notice the difference. I'm guess I'm with Wes on this....run what you want....you're the one that has to be happy with it.

Good Luck!

Tracy

 

Since we're calling B.S. What was your redline? A 390 at 6000 rpm will only move 670 cfm IF it is 100% efficient, which it isn't. 70% would be real high and that will only give 490 cfm. That means that flat out you aren't moving enough air through the carb to properly atomize the fuel. All the DP is doing for you is dumping enough raw gas into the air flow to keep it from backfiring when you jump on it. It may run real hard, but it will run just as hard or harder with a smaller carb and definitely more efficiently. A 750 on a 390 (or 428) is over carburated under about 8,000 rpm.
Spent enough time on the dyno to know

Gary

 

Do the Math? The "math" isn't an accurate guide to what any engine pulls at WOT. It's only what an engine that pulls 1-1/2" HG at WOT will draw with those sized oriifices. I agree a 750DP isn't a good choice, a tad on the big side, a 3310 750 would be better. Now an 850DP IS too big for a mildly built 390. Had one on my 68 Merc (no other choice at the time) and if you nailed it from a dead stop, it would kill the motor. Nail it at 3 grand and it took off like a scalded dog. If he wants a DP carb a 650 would be ideal.

 

Here you go Bear, figure out this: My 331 would do 90mph in my 89 Ranger on the center 250 cfm (Holley's rating) carb. Rpms at 90 was 4030 (1:1 final in the 4 speed, 3.73 gears with 28" tires) According to Holley's rating formula, the motor would be pumping 386 cfm at 4030 rpms. So tell me how that's possible with a 250 cfm carb?