Some of you my remember my original post. Here are some pictures. I am mocking it up and designing fuel supply and linkage. Checked the carb #s. They are 381 CFM. Translates to: 269 4 bbl CFM x 3 =907 CFM total. The end carb base plates are CNC aluminum GTO Tripower bases. Had to space them up 1/2" to align the tops. The end carb tops are pontiac tripower tops that are 1/2" shorter than the center carb. Center carb is a marine carb with side inlet and elecric choke. Line up good now and the dumpers shold flow good! Have to fabricate an extended throttle plate rod for the center carb. Here is the original link: http://forums.corvetteforum.com/show....php?t=1319285

 

Got the fuel line modified to work, the electric choke will clear everything and the fuel solinoid will hook up off the rear of the fuel block. I will have to drill the block and tap it. Next is the center carb extended shaft to hook up the linkage on the pass sid. That side is getting pretty crowded but It will work.

 

That's gonna look sharp when you're done

 

I take that as a huge compliment looking at what you are building! This setup should feed my new 500 hp 383 plus the 150 nitrous shot. I have a slow Machine shop. Good thing because the intake system has been a project. Waiting on parts AGAIN!!

 

I finished the linkage today. Had to drill and tap the center throttle shaft and a 1" rod the same size to accept the linkage arm. Then cut and grind the top of the linkage arm and remove 1/4" of the bottom of the choke housing to get it to pivot. Then had to grind the stop bushing and linkage arm on the rear to clear the rear baseplate. The linkage is infinitly adjustable. You can adjust what position the center carb kicks in the end carbs from 1/4 throttle to 3/4 throttle. At any position you can also adjust the stop to open all three wide open. Took 7 hrs to make it fit and work correctly! Time for a brew!!

 

OK 63mako the carbs look like a first rate job, but those aluminum
blocks clearly state they are to be run at 10,000 RPM. 195 AFR
heads will not cut it on a 383 at 10,000 RPM. My back porch dyno
tells me you need a set of 12 degree 299cc raised runner brodix heads
they flow 400cfm. Let me know if you decide to build a bigger small block Dart and brodix have some heads that will flow more then
400cfm. You are buillding a 10,000 RPM 383 and running three twos,
have you lost your friggen mind, you must have a 6500 to 10,000
rpm tunnel ram or a good single plane with holley dominator. You
are not running one of those damn hydraulic rollers are you they
crap out on you at around 6500-7000 RPM.. let me look at the
bottom of the page of my Crane catalog for a solid roller. I have not had a chance to check this cam out on my back porch dyno yet
but this should work well for you CRANE Part # 118471
rpm range 6800-9800
int dur. .050 286
ex.dur. .050 294
int. adv.320
ex. adv.328
LSA 112
int. lift .786
ex. lift. .757
14.1 minimum comp.
388 cubic inch or bigger works well with muti-stage nitrous or 35
lbs maximum boost with 7.5 comp.
PS man I don't know about all this maybe you should just get
some 7000 rpm aluminum blocks its going to be expensive
to buy all this stuff and you may break more parts at 10,000rpm,
I think it would just be cheaper to buy the 7000 rpm blocks.

 

They were custom made by 10,000 RPM in California back in the 60's for a GTO tripower setup. Notice the hard lines for plumbing, Old S RPM limiter will be set at 6500. And yes, I may have lost my friggin mind after all the crap building this has put me through.

 

Nitrous system do not rely on the carb setup to feed them. Other then looks what are you gaining with 3 carbs over one good 4 barrel? YOu are gaining more problems in the tuning department, jetting changes become 3 times the work and 3 times the chance of trouble.
One 4 barrel minimizes the problems, the tuning and will 3 carbs really outproform a single one???

 

Neat project! Dare to be different! I like it. Make sure you have the shop dyno-tune the motor WITH the 3 deuces on it to save you a lot of incar tuning. At least to get you close.

That ole vettes gonna roll on the spray!

I got a buddy with a 66 coupe w/388" fuel injected with a 200hp shot. It makes 407rwhp before the spray and he went 11.10@128mph on drag radials.

 

63mako Glad to see you are running the three deuces they look great.
If I go to one more parking lot car show and see one more
single four barrel small block chevy I think i'm going to puke. its ok
for vette/camaro guys they have a closed hood most of time but
when you see 32 ford hot rods with the common old small block
chevy and a single four how boring can you get. Was at a parking
lot car show two weeks ago a guy had found and built a fairly rare
32 full fendered ****** coupe top chopped 3 inches, look under the hood
boring small block chevy one four barrell. I will be using another
boring small block but mine will have offys low rise cross ram
with two holleys. by the time I get done moding the intake on the bottom to match my heads the manifold will have even longer runners
and sit around two to three inches higher. three deuces
PS You know offy still makes the manafire four deuce manifold for the big size deuces, how about an extra deuce. four deuce large carb offy
part # 5263

 

I agree very with the three dueces, I would run that setup if it cost me 10HP who cares

Kinda girly boy stuff with 112 LSA if you ask me

 

Motorhead I agree 112 LSA does look a little girly. but for some reason when cams get extremly radical they do that. Did you know that
500 cube big block pro stock engines run LSAs of 120-122 and
lifts over one inch. I would have guessed the one inch lift but the
120 to 122 LSAs surprised me.

 

thats cool looking.

 

The reason for the wide LSA is due to the huge duration of the cam The LSA has to be widened or you have too much over lap and the valves would never be closed at the same time. A modern Pro-Stock motor is tuned to make power at a very high rpm in a somewhat narrow power band, a wide LSA does this.

I agree the set up looks killer, I have one concearn though. Since you are running a low pressure nitrous system your nitrous side fuel pressure will be in the 5-6 lb. range (typically). Since your fuel side selinoid is down hill from acceleration the fuel will have to push its self up hill to the front selinoids under acceleration. This conditioned is worsened by the cool looking twists and turns of the hard fuel lines going to the plates. This could potentailly cause a lean condition to the front selinoids. I do not have the math skills to figure out what your fuel pressure drop would be from the selinoids to the plate, but I would bet it would be pretty substancail.

This could be fixed by mounting the fuel selinoid in front of all the plates.

I hate it when my spell checker don't work

 

Here is a pic of the nitrous system on my race car. You can see how far in front of the selinoids I have the fuel presure regulator. There is 20+ pounds of pressure going to the regulator and then down to 5.6 to 6 lbs. to the nozzles.

 

With the tripower plates I have 3 spray bars for more uniform distribution of the nitrous fuel mix. The end carbs are just dumpers, basicly primaries. They have no idle circuits, no choke, no power valve. Just 2 jets and an accelerator pump. The are tied together and operate at the same time as big secondaries. The center carb has Idle circuits, choke, power valve , Ect. You jet the center carb to run up to 1/3 throttle with correct A/F mixture. Then jet the front and rear to maintain correct A/F mixture beyond their opening point. Really pretty basic. With this setup you can adjust when your secondaries open. It will take a little more time to dial in on the dyno but once it is done it should be maintainance free. I am building a show, street car not a race car. My nitrous and fuel are jetted at the solinoids and it is setup to be able to fine tune my fuel supply with the regulator as the carbs will run fine between 4.5 lbs up to 9 lbs of fuel pressure. Nitrous fuel solinoid jetting now is sized for 6 lbs of fuel pressure. The spray bars were drilled to provide a 150 shot max to keep the pressure and flow equal on all the plates. I don't know if 3 carbs will outperform 1 4 BBl but I will find out soon! If I lose a little I really don't care. I know it won't be much and the look is going to be worth it and the nitrous will make up for anything I do lose!!

 

I seen the 4 duece setup. There is also a six deuce intake but it is about what I can afford, tuneability and how much brain damage I can take trying to make it all work! This one has been pretty trying. Waiting on Rebuild kits, air cleaners ( K&N 66 GTO 5 1/4 x 2 with chrome tops) to clear my hood. I also already have mounted 58 Pontiac tripower emblems on the hood.

 

The carbs, nitrous system and distributor will all be dialed in on the engine dyno before it leaves the shop! If it takes more dyno time I don't care. My engine builder is looking forward to doing it. He want to see what he can pull out of this setup. Looking for low 11's Maybe high 10's if it works as I expect

 

[QUOTE=Little Mouse]4500-8000 ?? I highly doubt it. What is your motor build, cu. in. cam, etc, etc. ??
The three plates are drilled for a total of a 150 shot ? How big are the holes that are drilled ?

Other than the cool factor, there is no reason for a crank trigger distributor. I would use a plain ole MSD. The digital box is nice, but again, overkill.

 

[QUOTE=69 N.O.X. RATT]That is not me, it is Little Mouse. My motor will see 6500 then rev limiter I am running a MSD 6ALN box and MSD distributor, Engine specs are 383, 10.2 to 1, Billet main caps, All ARP studed, forged bottom end , 4340 Eagle lightweight crank, Callies 6" H beam rods, Mahle high silicon low expansion forged pistons. Comp cams Retro roller with 520, 540 lift 236 242 duration @.050 114 LSA, 110 centerline, AFR 190 heads Comp pro magnum roller rockers. The wide LSA is Nitrous and street friendly. Drilled the plates 2 years ago when I put it on on my Small base tripower setup. Don't remember the size but I do remember doing all the math to figure it out. Triple checked the sizing from 3 different sources and found out what size the holes on the spray bar needed to be to run 150 hp shot. All three sources figures came out the same sizing. This was done because I wanted to jet at the solinoids rather than the plates and was looking to maintain balanced pressure at all the holes to avoid a lean condition at the front plates. Too large of holes would bleed the pressure at the closest bar and could have resulted in a lean front plate as you said earlier. Been there, done that! You have an awesome looking setup there. I seen your post on your new best time. That has to be a major adrenaline RUSH!