SBC tunnel ram carb change , READ... MORE CFM

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Re: SBC tunnel ram carb change , READ... MORE CFM

Postby pdq67 » Wed Sep 13, 2017 11:22 am

What would happen if you installed two in-sync, match tuned, 750 Q-Jets?

Seems to me that you would do away with tinkering with Holley's all the time...

Install them so that the primary venturi's face each other with the big ones over the manifold runners.

Like this --

Oo-oO
Oo-oO

What do you think Big Joe?

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Re: SBC tunnel ram carb change , READ... MORE CFM

Postby Tuner » Wed Sep 13, 2017 1:16 pm

joespanova wrote:
F-BIRD'88 wrote:If bigger carbs gained 50 hp and that made the car a little faster, will that make you more money or make the girls like you better,?

Its funny you mention that...............that's exactly WHY I'm doing this , a-hole.


Anyway.......it all started from needing new boosters in my 660's since some of them were very loose. I called a few shops and no one wants to mess with 660's. In fact the first shop I called was Patrick's shop ( Pro Systems ). My request was , can you install new boosters and while you're here is there anything I/we can do ( like the old 850 base plate mod ) that's worth the time and effort. No interest.
So I left a message , he called me back , we talked and he wants to sell me a couple 750s he practically guarantee's will make the car quicker.
I'm not easily convinced.
See , its like this................I run some nostalgia stuff , the 9.50 / 6.0 stuff. If its possible the 750's get me to the next index ( 9.25 ) , why not try it. Actually I could care less anymore.....but it was interesting to hear opinions anyway.
Certainly carb shops want to sell carbs...............but then , that's why I'm here now...........for educated " unbiased" opinions.

You don't need new boosters, just tighten the ones that are in the carb, either with a booster swaging tool, or, clean them up good with chlorinated brake clean and align the boosters centered and square with the bores and use penetrating locktite.

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Re: SBC tunnel ram carb change , READ... MORE CFM

Postby F-BIRD'88 » Wed Sep 13, 2017 1:54 pm

Looks like Pdq67 is jumping on the band wagon. Has the Dual Q-Jet 2x4 bug.

Well, It will either run faster, run slower or run the same. But will sure be more interesting.
I like your orientation for on a tunnel ram.

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Re: SBC tunnel ram carb change , READ... MORE CFM

Postby Tuner » Wed Sep 13, 2017 2:23 pm

A backwards mounted QJet will have a dry secondary if the car can launch with vigor. [-X

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Re: SBC tunnel ram carb change , READ... MORE CFM

Postby pdq67 » Wed Sep 13, 2017 9:37 pm

Tuner wrote:A backwards mounted QJet will have a dry secondary if the car can launch with vigor. [-X


Thanks Tuner, didn't know this.

My bad.

Is there anyway to get around this issue?

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Re: SBC tunnel ram carb change , READ... MORE CFM

Postby Old School » Wed Sep 13, 2017 11:26 pm

pdq67 wrote:
Tuner wrote:A backwards mounted QJet will have a dry secondary if the car can launch with vigor. [-X


Thanks Tuner, didn't know this.

My bad.

Is there anyway to get around this issue?

pdq67


Yes, A Holley with jet extensions.

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Re: SBC tunnel ram carb change , READ... MORE CFM

Postby In-Tech » Thu Sep 14, 2017 12:22 am

In-Tech wrote:Hi Joe,
Typically with tunnel rams the fuel curve gets all facked up, mainly going rich on the top end. A pair of bigger carbs is never a bad idea but if you want to deal with what you have, get to tuning. Since you have a loose booster maybe some downlegs are in order rather than the crappy one's that come on the 6224's. I think I have some 6109's laying around, I'll have a look later today.

Fun little tunnel ram story, a bud at a boat shop with a pickle hydro has me work on his carbs, pair of dp 750's on a 454. He was tickled that he was able to cruise the entire 5mph zone at havasu without reving it up to clean it out multiple times from loading up at idle :roll: Wet exhaust and I wasn't going to ride in the boat a friendly bet emerged with the other guys in the shop. A paid lunch bet that we could have the engine pulled, dyno'd and back in the boat by noon equated to a 75hp increase and of course we won the bet too. =D> We're at the river for the maiden voyage and he came back with a grin ear to ear saying it picked up 15 mph and never quit pulling(everyone here that knows a hydro/tunnel knows the faster it goes, the less boat in the water and the faster it goes as long as rpm can increase).
Anyhoosit he says I might need to readjust the carbs as it's not idling so good. I hit the recall on the tach and it's 8800rpm [-X Hey dumbass, you floated the valves and bent some is why it's not idling...smile gone :mrgreen:


Hi Joe,
It turns out I do have that box of all the parts from the 750 6109's. The metering blocks are no good since the boat was pulled from the lake. :lol: Do you have room for these carbs on your tunnel ram? If so, I'll be your huckleberry. :mrgreen: When is your next chance to go to the track and do a swappy swappy on the same day? I'll fix them up for ya if you would like to try them and if so, give a bit of time for me to get them re-dyed and some other mods so they are pretty. =D>
Heat is energy, energy is horsepower...but you gotta control the heat.
-Carl

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Re: SBC tunnel ram carb change , READ... MORE CFM

Postby maxracesoftware » Thu Sep 14, 2017 3:43 am

joespanova wrote:Currently running 2 4224's ....never a problem. But , these carbs still have the 660 base plates and except for the secondary metering block conversion and the choke horns milled off , are box stock. The intake is the Victor Ram.
So , I call Patrick James and he's adamant that the 660's are "dated" and in 2017 a pair of 750s set up for my application will perform better.
I'm not convinced yet as I've seen some stout 434s make big power with a single Dominator. So why would my 377 want more CFM?
Any changes to improve performance DO seem to have hit a "wall" though. Larry Meaux seems to think I have a restriction in the induction somewhere...............and since the only things never changed are the 660s I'm beginning to wonder.
The cars runs high 9.30s @ 141ish. 2975 lbs.


Joe says he ran :
I ran two 1050 Dominators on a 377 way back in 1990- It made 710 HP at 8000-- We turned it 8800-9000 in the car-
It ran 970 at 139 with a 2 speed powerglide and 5.57 gears
JOE SHERMAN RACING

you're running : "The cars runs high 9.30s @ 141ish. 2975 lbs with 377cid Brodix Track 1 Heads 2.080/1.600 valves"
i think you are doing great !
theres BBC and SBC bigger engines with better Heads that are not going as fast as you :)

i have (2) Murray Jensen modified + Dragstrip proven 660's with 850 base plates
likewise an Edelbrock Pro Ram II i band-sawed plenum apart , maxed-out Ported, then welded plenum back together
that should be much better than yours

if you want to drive down here to my Shop ( take a Vacation ... have some fun Dyno testing :) )
i'll give you a "Free Dyno Day session 10+ hours " ... you just supply about 15 gallons of your Race Fuel, any oil + filter changes
plus any gaskets + parts you want to test

need to bring your Headers + gaskets + bolts , etc
any other exhaust system parts ?

your Starter , shims, bolts, water pump ?? , Vac Pump , valve cover gaskets, timing light, etc
any and all spare parts like Rockers, pushrods, Jets, needle/seats, spark plugs, distributor cap/rotor, wires, etc
Intake gaskets to use in manifold swaps ... likewise a few Carb gaskets and Bowl + Metering Plate gaskets would be nice to have on hand

Bring your Weather Station or whatever you are using to measure/record Dragstrip Weather conditions
so i can see how yours compares to mine ... very important for correlations !

the single biggest mistake i see Racers make => is not to bring every and all spare parts to the Dyno
because you never know what little part might delay or prevent us from Dyno testing ?

i'd like to first Dyno test your Engine exactly like your last Runs you've made to establish a Baseline.

bring ET Slips + as much Run Data as possible .... we'll see exactly how much TQ and HP you were making
... along with my Softwares, i can see the HP you are making at each and every foot distance down Dragstrip
to compare to Dyno readings... very important to consider for a 4 or 5 speed manual trans because of RPM/SEC Rate in 1st thru 3rd gears
... its going to be way higher than 600 RPM/SEC on my Dyno tests

then start changing parts
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Re: SBC tunnel ram carb change , READ... MORE CFM

Postby maxracesoftware » Thu Sep 14, 2017 4:46 am

Joe , i forgot about Tim Owens SBC 377cid he ran SuperShops long time ago in New Orleans area
this Pickup Truck had a Powerglide/Converter , i can't remember what it weighed ???
i know he was super happy when it ran 8.90's ... that was his goal .

SBC 377cid with Brodix Track 1 Heads Ported by Meaux along with Edelbrock ProRam II Tunnel Ram Manifold
734 HP on Meaux's Dyno ran best 8.90's , mostly 9.00's all year


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Re: SBC tunnel ram carb change , READ... MORE CFM

Postby F-BIRD'88 » Thu Sep 14, 2017 7:04 am

You got some good offers to help get you where you want to go.


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