BBC thoughts

[prairiehotrodder]

F-bird - The guy in brockville won't ship it to me. I've emailed him 3 times. He also won't give me his phone number. I found a Weiand one as well but not having any luck on it either.

I also talked to John Dickey at AED and he will build me 750 tunnel ram carbs for $699 each. At first he quoted $999 for ones that had a bunch of CNC work on them but I think the cheaper ones will meet my needs. I am not in a hurry because the season is almost over here and it will be a winter project. I hate overpaying on freight and exchange rate so i'll just wait for the right deal. I may by a TR used but i'll buy new carbs.

I hope to make it to the track one more time and test my latest changes
- electric fan
- electric water pump
- advanced cam to 103 ICL

[F-BIRD'88]

I don't see the value in overpaying for the specialized/boutique branded carbs

that you WILL HAVE TO tune for your car anyway.

You will save a bundle by building and tuning your own custom carbs yourself

Then spend the money on Dyno tuning. You will come out way ahead perf wise
and spend less money.

For your street/strip purpose car consider using 2 Holley/Demon Street Demon 750 carbs
on a T ram. That you can dial in yourself....

I have a friend here that has been running 2x Eddy 750 AFB's on his t rammed Big Block Mopar
(that makes well over 750HP) Has not touched the carbs in 12 YEARS.

These were dyno tested and tuned against very well sorted out Holley tunnel ram carbs
on the dyno. The holleys while they did make a bit more power, DID NOT make enough more power to justify the BIG DIFFERENCE in cost..

This car runs a very low 9sec et and would run a 8 sec ET if it had the right transmission.
He is the opposite of you his car needs a 2 speed Powerglide but he likes his all Mopar 727 3 speed trans. (has to launch it in 2nd gear)(#2300 ish car)
I saved him a ton of money on the AFB carb choice advise and the dyno and track and street testing proved it. If you don't like AFB's try the "Street Demon" carbs.

[F-BIRD'88]

Will be interesting to see the track ET effect of getting rid of the engine driven fan and Water pump and having moved the camshaft.

[prairiehotrodder]

ok if i did buy a couple edelbrock 750's (#1407) where would i start as a baseline ? Like what needs to be done to them for a TR application?

[F-BIRD'88]

Start with the stock default jets and rods. The power piston step up springs may need to be changed so it can idle (in gear). Install a weaker tension step up spring spring. These carbs do not like a lot of fuel pressure. 5.5 psi is great.

I asked my friend all long time ago what he ended up with for jetting on his 2x 1407 eddies after engine dyno testing.
He did not remember specificly but said it was not a big radical change.
Then when installed in the car and on the street thru his 4 mufflers he find tuned the
primary metering rods a bit leaner from the dyno jetting for when the motor is fully warmed up.
Using a Innovate wide band ...

All he did was remove the 2 choke flaps on his. You can start with yours installed.
Even 2 borrowed 600 eddies will prove the point if you don't want to invest yet.
Avoid the 500's if max power is the goal. There is nothing wrong with them. They just won;t make as much power as the larger ones.
2X 800 Edelbrocks are NOT too big on that motor.

[F-BIRD'88]

You are a welder so you could build - fabricate the 2x4 carb adapter to run the 2 carbs on your current single 4 bbl intake to see the effect,, before investing. You will get the idea and get a handle on 2x4 carb tuning.
(And have some fun too. ) Got 2 carbs kicking around?

[prairiehotrodder]

don't tempt me.

i have about 10 Q-jets. I can't get motivated to do anything with them.

I think i'll keep moving in the TR direction and keep my eyes open over the winter.

[F-BIRD'88]

"10 Q Jets" ha hha you're all set... You only need 2 of them and you'll have a ton of spare metering rods and jets which you can customize those yourself to get a "range" of jets and sec rods to try out.
Picture 2 Qjets mounted back to back on a 2x4 carb adapter on your super Vic...

On the Qjets (2X4) it will all be about the dialing in of the secondary metering rods and hangers
for best WOT. power jetting... All that is done from the top... on them...
These carbs also do not like a lot of fuel pressure.

Beyond the WOT jetting (Secondary rods and hangers selection)
The low speed and "drive" is all in the primary jets and rods and the adjsutable "APT"

But then.... you fine tune tweek it all by making use of the PCV valve ports on the carbs to
create a adjustable air bleed(s) "idle eze" to both tweek the idle and it also tweeks the whole fuel curve
ALSO.... (much like tweeking the emulsions and HSAB's in a holley, except easy and basic, just +/- the bleed rate of the PCV as needed)... The carbs don;t know or care if the PCV is actually hooked to the valve cover or not... When you get it all finalized the 2 SUDO PCV hoses with restriction hook up to the air cleaner.
(Can be nice braided lines) Its your lil secret as to what they actually do...

this is what lets you get the primary throttle blades in correct idle position at idle on the 2 Qjet carbs
for the right idle rpm and the correct throttle opening at idle with the 2 Q jet carbs.

If you have another ///any V8 ///mule test motor/car on hand you can do 90% if the initial setup of the 2 carbs on a 2x4 adapter , first.... then move it to your 540BBC for final dial in tuning.

If you just don't like it, stick the 2x Qjets back on the shop shelf and give the 2x4 carb adapter to the wife to use as a flower pot....
You can try/set up the carbs first, mounted inline.... then try them mounted back to back for effect....

You can make up a prototype////test 2x4 carb adapter out of thick sheet metal and a few aluminum or wood carb spacers. I'd make it about 3.5" tall.... plenty of transition slope in the adapter....

You can still do the tunnel ram too....
You could end up with 2x Qjets + 2X Edelbrock AFB's and 2x home built custom Holley 750 HP carbs
all set up for on a tunnel ram (or the 2x4 adapter) AND STILL have less money invested than if you just bought 2x $699 tunnel ram carbs.

ALL these will work real well once dialed in... And it will keep you plenty busy in the shop all winter
playing with it.

if you can dip a carb metering rod into a lil pot of HOT melted solder and file it to size you can make your own custom carb metering rods for test/tuning.... (dip the hot metering rod tip in soldering flux first then dip it in the solder to build up the tip diameter)(file to size)
You only need a "range" of 4 to 5 pairs of secondary metering rods for each Qjet.
and say 4 sec hangers You make them too.

[F-BIRD'88]

If you make up your own custom made drop base dual quad air cleaner and carb scoop assembly the drop type custom air cleaner base will cover up the 2 carbs on the motor and no one will be able to tell they are 2 Q jet carbs or 2x edelbrocks or 2x 750HP (Built by PrairieHotrodder Carbs inc) Holleys

Paint the fiberglass areo "shaker" carb scoop the same colour as the car.

[prairiehotrodder]

2 q-jets with 2 cables and 2 gas pedals side by side. Drive on one untill i want to race then step on them both at the same time. Be like a double barrel shotgun with 2 triggers!

[F-BIRD'88]

I never thought about it like that.. Thats brilliant..! I almost spit my coffee when I read that... Ha A...

You got to do it now....

[F-BIRD'88]

How is this: You got a lever on the console that grabs the other carb cable
so when you rug it, you can give'er "Two Scoops o' Raisins"


Your kid will love that!!!....

[F-BIRD'88]

Another way to make your own custom Qjet or AFB metering rods "range of sizes" to help you
dial in the carbs for a 2x4 situation is to use brass (brazing rod). Preheat the metering rod tip and dip the end in brazing flux, The add the brass (brazing rod) with a acetelyne torch.
File down the brassed tip diameter size as needed. Now you have a set of rods to adjust the jetting.
2 sets of 4 each of different secondary metering rods should cover it.

For the range of rod hangers make up a lil hanger stand jig that sits on the work bench.
Sit the rod hanger on the jig and measure the distance of the rod finger holes to the bench.
Bend the fingers of the hangers to get different heights ... say +.030" +.050" +.075" +.100" etc as required.
2 sets of 4 different hangers will do the 2 Q jet carbs.

Again on the 2x4 2 Qjets the WOT full power power AFR "jetting" adjustment will be all about the 4 secondary rods and 2 rod hangers and air door tension setup of the 2 carbs.

At WOT the 4 primaries are essentially just along for the ride.

Idle and driving- part throttle "cruising" is all about the primary rods, pri jets, primary metering rod step up spring and APT adjustments of the primary side of the 2 carbs. You will have square even oriented "4 corner idle" when the 2 Q jets are mounted back to back on the 2x4 adapter.

When at idle and when idling "in gear" (auto trans) you ideally want the primary metering rods of the carbs to stay down in the primary jets "lean" at idle. The tension and free length of the primary power piston step up spring controls this... With the big racey cam and low manifold vacuum at idle you want a spring with lighter weaker spring tension than oem stock...
There are different vacuum rated tensions AC Delco GM part# springs for this tuning...
Or you can find your own suitable springs that fit the Qjet.

[pamotorman]

I made my custom Q jet secondary rods by machining a flat on the tip. you can do the math to see how much flat you need to reduce the area to what you want

[F-BIRD'88]

I found a Weiand one as well but not having any luck on it either

If it is the one from Welland/Port Colborne with the 2x 750 DP holleys on Kijiji,
I know that guy. He was telling me about that BBC Weiand tunnel ram he has for sale here.

It is a bit over priced.... but.....whatever....