514/635 h.p. What Carbs 2X4?
 

Need help selecting 2X4 setup, any help would be appreciated. Blue thunder and___________carbs. motor dyno at 635h.p. 4 speed,ford racing crate (514)

How did you dyno your motor without carbs?

I would put two Holley 600 CFM vac secondary, single feed carbs on there, with downleg boosters.

thanks for responding. engine still has 1150 dominator carb on. runs great at higher r.p.m. want to make more streetable. can you reccomend some one to make mods to new carbs/

I'm not sure where in NJ you are, but my mechanic/builder here in West Chester, Pa. does a lot of work w/514s. His Cobra motor sounds similar to yours. Roughly 600hp. I can give you his info if you want.

Steve

I live in central jersey and that would be great if you could forward his phone # thanks

A 750 cfm carb would be more streetable and give you all of the performance on the top end that an 1150 or twin 4's would give you. 750 cfm will support close to 700 hp. Scott

Sent it to you by e-mail.

Steve

PS, come on down to PA in June and show that car off at our show!! :D

I disagree with coyled, a 750 would lower the top end HP potential of that motor.
It would be more streetable however. 850 wouldbe more appropriate for a small street carb

Really like the looks of 2X4 set up! which carbs? 1850's (600)tricked what do ya think

I have 2 600s on mine(holleys) and it runs sweet on the street. I run a small progressive between the carbs so only one of them opens when cruising around town. But watch out when the vac secondaries open up. What a monster...600hp in a 2800lb car is insanely fast be careful...I have been humbled, I had no idea.

Blue Rooster are your carbs right out of box or have they been worked?

Two 660 Hollys on my 427 (bore/stroke to 454) making 690 h.p. They tried bigger carbs during dyno and got LESS h.p.

Over carb is the MOST common problem on custom engines. Twin 600's might work, in my case 660's were the ticket.

Ernie

They were both out of the box. I had the car dyno'ed last year at Bruce's Speed shop in Rockaway, and we re-worked one of the carbs. So now I have one stock and one massaged a little. The one we took apart is the carb that opens first. They replaced the metering block and put in larger mains. If you check my gallery you can see both dyno runs and see the changes that the jetting made.

I am running the 514 bracket engine with the Holley 1050cfm. I drive mine all around town with no problems. That is the carb that ford racing specs for the engine. I have the idle set at around 1000 rpm.

I run 2 Holley 750 vac secondarys on my 514.
The engine is not a crate motor, it has about the same cam only flat tappet. I had The Carb Shop work them and when I chassis dynoed the car the A/F was 12.6 across the board.
What I liked about them was they put each carb on and engine dyno before you get them back so they are dead nuts on to each other. It was $830.00 for the pair on top of what the carbs cost.
Be prepared, that single Dominator will make more hp than the 2 will, but doesen't look as good (my oppinion).

My car made 513 rwhp & 513 rwtq so that's about 620 on the motor, not bad on 91 octane pump gas in California.

I know. I saw your picture that got posted.

how big do holley carbs go in the 1850 series?would like to use stock cobra linkage fuel log and stelling air cleaners

Use a NEW 850 Holley HP series, single 4 bbl with mechanical secondaries and double pumper. Use Holley recommended jetting. Call them, talk and listen.

I cannot stress enough the improvements in the new HP series. Don't even think about rebuilding a 3310 or regular 4500 series from the past, no matter how nostalgic you are about old is best. They were only so so at the bottom, at best, but very good on the top in those days.

That's why guys are comparing old Holley rebuilds to new expensive Barry Grants and Demons and saying how much better they are. Sure, than the old Holley, you bet. But the new Holley is just superb.

This will provide everything on the top and bottom, because the new HP series are excellent metering at low air flows, which allows mechanical secondaries on the street.

Dominator doesn't meter correctly at low velocity on the street, particularly when cold. Might be fixable, but not by me. Pops, leans out and then floods when warm at low rpm and WOT.

Install a choke if you live in the cold weather. Costs hp remember. Interfers with airflow around the horn. Florida doesn't need one. Learn to start hot and cold w/o choke. If it floods keep throttle on floor until it leans out and starts. Let it warm up a little before you nail it.

If you owned a ferrari in the 50's or 60's you would know to let it get warm first even before shifting and you would learn to live with popping and spitting Webers until they got a little warm and it took a while.

Oh, yea, and don't forget the air filter should be at least 3" tall and the largest dia. you can fit. Skip the little pot lids, they are very restrictive. Look at the NASCAR filters. They work.

If it severely interfers with your distributor, it is almost big enough in diameter. Grind away anything too close and insulate.

In most dyno tests I have seen a well set up single carb will almost always equal dual carbs with alot better drivability. Look into demon carbs as they have been shown to be a tad better in the hp field than holleys. If you do the math for your engine 514 cubes, max rpm 6000 and a volumetric efficiency of 90% you only get about 800 cfm needed, a good 850 cfm vacuum secondary carb would make you a happy man. But then again what works and whats "sexy" are two different things dual quads look great but are a pain to set up, where as a good sinlge quad carb with a vacuum secondary would actually be much more enjoyable on the street.