Some Carb Advice

"winze" wrote in a message:

Look who BENCH RACES!!!! I have yet to see any proof that you race. All I see you post is information that you got from a magazine, or a repair manual. For your information, if someone can pull their front tires off the ground, that means they know how to make a car hook up. Why do you think most race cars have wheelie bars? To control how high the front end comes up in the air.

BTW...There's more Pinto owners than you think. I'm not the one trying to impress anyone, you are. I'm just passing on information from results from things that I have done, not what I read about.

Gary

"winze" wrote in a message:

Hahahaha...So now your an NASCAR expert because you live in the same county as a couple NASCAR teams? FYI, those carbs are not BOX STOCK!!! If you know so much about NASCAR engines, why aren't you a CREW Chief on one of those teams? Heck, even the intakes aren't box stock. The big teams buy blanks and they mill their own. If you look long enough on eBay, you can find someone selling a blank NASCAR intake manifold, from a team that folded. And as far as if you have enough money you can buy a competitive NASCAR, sure, if you have enough money, you can buy anything! As far as that goes, if you have enough money you can build one too!

Gary

Well the 750 HP it is! And it was installed yesterday. First Dyno report... 448rwhp with initial tuning. That is enough for me, I am not sure I need anymore.

So here is the final config

347 Stroker Probe forged pistons and crank AFR 185cc Street Heads with 61cc combustion CompCam 1.6 roller Rockers and roller tappets Edelbrock RPM Airgap Intake Holley 4150 750cfm HP DP - vacum secondaries Aeromotive FMU and the A1000 pump MSD Ignition system using the 6AL Tremec TKO 600 transmission FR aluminum driveshaft 8.8 31-spline Auburn Pro with 3.27 rear Rear - Baer Claw Pro Plus with 31 spline axles, 12" slotted & drilled rotors Front - Baer Claw Pro Plus with 12" slotted and drilled rotors FR 17" Mach-1 Wheels Khumo 245/45/17 Ecsta MX tires Custom 6-point roll cage Full length subframe connectors Jacking rails K Member brace KB Extreme Matrix Kit Koni Sport Struts and shocks H&R Super Sport Progressive rate springs Cooled with the Fluidyne AL radiator Corbeau Seats with 5-point restraints Fuel Safe Fuel Cell

Will be taking it out on the fisrt rad test drives this weekend. I will post the results if anyone is interested.

This was my very first new car that I have held on to for all these years. I am almost as nervous about it now as I was when I first got the car with 16 miles on the odometer. I just need to figure out how I am going to paint it next. Any suggestions? My first thought is to restore the paint to the original 1983 GT and have as a somewhat of a sleeper......

Thanks for all of the postings! They were helpful and interesting!

Respectfully,

David

"David Eaton" wrote in a message:

Hehehehe...Once you get used to it, you'll want more! So where did you end up setting the idle rpm at? Did you try it down below 1000? We had mine down to around 800, but ended up putting up to 1100 in park. Did you ever have the car to the drag strip before the engine build, and do you plan on taking back once you get it broke in? If you do, be sure to let me know how you do!

Gary

We are still tinkerng with it. Right now the idle is set at about 950 rpm, but that is going to change; all of the little adjustments with a new engine and all the rest. Right now it is running a little rich and the timing is just a hair off. But isn't this really where the fun begins? Sorry my goal is not to 1/4 mile with this car. I am not a drag race kind of person. I have never had this car at a strip. I have had it in its younger days make the trip on I-10 from LA to Phoenix (360 miles) in 3 hours and 25 minutes city limit to city limit. Of course that was not during "normal hours" or the CHP would have really had a field day with me.

I am setting it up for road racing and embarasing New Cobra drivers who think they are too powerful. You know the types, they are are the ones who buy the car only because they think it is cool to have a hot car. But there is no Mustang passion or heart behind them. And they have no real driving skills. These are the people who create parts cars for the rest of us! I plan on running in the Nevada Silver State race. I am going to keep the HP set and run out of a lower class and see how I do. If all goes well, then I will get a little more extreme on the powerplant, but in road racing it is more about controlled durability so the overall horsepower is not quite as important as the chasis stiffening and suspension. There is one guy in the unlimited class that has a mustang running at almost 200 mph. That is not where I will end up. I don't have that much cash, and what can I say I am not as daring as I once was. This car should be somewhere in the

140-160 mph class area. I plan on maxing out around 175-180 mph. They do an anlysis on the cars configuration and calculate a Max speed of the car that you are not to exceed. This way it is still semi-street able. This is where the engine swwapping comment comes from. In a few months, Paxton is comming out with a blower for the 4-barrel 5.0L HO engines. Add about 8 pounds of boost, and I think that will be all she wrote for this old pony. New life and breath for the car that never let me down or left me on the side of the road!

Thanks for all of the help!

Respectfully,

David

Here is a site that I have used:

I think that the 750 is the ticket for you. I am building a 352 stroker with the same stuff you are:

3.4 stroke .060 Mahle Coated forged pistons Comp 270HR roller conversion Crane roller rockers Powerheads ported, 54cc 1965 heads (flows same as AFR165) Air gap ported manifold Lower girdle and a reworked 1965 650 Holley for shows and a 750 for all GO>>

I am putting this in a 1965 GT Fastback in about a month.

Dom>Hi,

Well the 750 HP it is! And it was installed yesterday. First Dyno report... 448rwhp with initial tuning. That is enough for me, I am not sure I need anymore.

So here is the final config

CompCam 1.6 roller Rockers and roller tappets

Holley 4150 750cfm HP DP - vacum secondaries

?8.8 31-spline Auburn Pro with 3.27 rear

Well almost 500 fwhp looks easy,the only problem I see is that the cam you claim you're using is not a roller cam! so how did you use roller tappets? and the 750 DP holley is mechanical secondaries, not vacuum secondaries?

Great carb calculator!

A 347 ci engine at 6500 rpms with 100% V.E. requires a 652 cfm carb!

"winze" wrote in a message:

But you entered in the wrong rpms. The redline for his combo, is 7000 rpms. I think it came up with 702 or 703 cfm for the right redline, but the calculator doesn't take into consideration for better flowing heads and intake. That calculator is generic, and only gives you a starting point.

Gary

"winze" wrote in a message:

FYI...They modify the venturis (not the throats), the emulsification tubes, and change the air bleeds to get every bit of HP out of a motor. There is one version of the 750 that has screw-in air bleeds to make it easier to tune the carb. They have one carb setup for the short tracks, and another one for the super speedways when they are required to run the restrictor plate. Sure, they LOOK stock, but if your were to use a caliper & a mic to measure every part of the carb, you would find that the carb on a NASCAR has been modified.

Gary

More big numbers? near 500 fwhp & 7000 rpm,are you forgetting this is a factory 5.0 block! You need a reality check, the engine might turn

7000 rpm but the % of the time its at redline is small, It will spend alot more time on the way to redline than actually being there & 100 % V.E is allowing for basically no restricion on the intake & exhaust.

Check your sources! Page 30 of the Summit Racing Catalog lists all of the variations of the 4150 HP Carb Their catalog part number HLY-0-80529-1 is a Holley 750cfm with vacum secondaries and downleg boosters. This is the carb on my car. The cam, well there I cut and pasted the wrong one. I am mixing up this engine and another 5.0 that I am bulding as a race only 347 for the road racing I plan on doing. It is not a roller cam based engine. So I will need to check back with the shop that has done the work and get the right camshaft.

Respctfully,

David

These calculators are not very good, I agree. The calculator does not take into consideration the heads as you say nor the increased volume and flow of the intake and exhuast manifolds. The other thing I see missing is anything to do with the stroke and bore. It seems to me that the fuel needs for an engine also depend somewhat on the compression ratio too, but I may be wrong. As I said, I am an engineer, but not one of the mechanical varieties - I am an EE RADAR guy......

Respectfully,

David

"winze" wrote in a message:

I can tell you from experience, with the cam David used, it will rev very very fast, at least it does in my 306. If you think a properly prepared stock block can't handle 500 hp at 7000 rpms, guess again. Don't forget, his dyno results were at the crank, not at the wheels. The most important thing is having it internally balanced. My friend with what you call a POS Triumph, shifts his car at 8400 and goes through the traps at 8400. All with a properly prepared stock block.

Gary

"David Eaton" wrote in a message:

The missing key is cam specs. The larger the lift and duration, the more air/fuel is needed.

Gary

"David Eaton"

Yep, there's the standard 750 vacuum secondary carb, the classic double pumper series, the Street Avenger series, the HP series, the HP PRO series, and a Super Charger series. The Street Avenger & HP series are available with either vacuum or mechanical secondaries. He probably stopped reading once he seen the 750 HP.

Gary

The results were 448 rwhp (rear wheel hp) thats near 500 at the crank, a drag car only sees max rpm for a small amount of time, not sustained

500 hp at 7000 or 8400 rpm and if you knew holley carbs, DP means double pumper & they don't have vacuum secondaries. Turning a 302 8400 rpm just for bracket racing doesn't make any since either!

Here is an update on the caM it is the Ford 289-302 Xtreme Energy XE294H Cam from Comp Cams

Sorry it took me so long to get this information updated but I have been a little busy....

Car squeaked by emmisions and is now on the road!

So far, no tickets....... knock on wood!

David

1983 Dark Red GT, T-Tops, Holley 750 HP DP and more Still tweaking the tuning a bit, but when does that ever end.......