Throttle Body Question (street/strip 347sbf)

[patrickbrown]

I think three duces would look cool on that thing. Or maybe go for a Weber look with eight singles or four duces.

[C.Anderson]

I think three duces would look cool on that thing. Or maybe go for a Weber look with eight singles or four duces.

You have to realize though...I'm limited by the plenum configuration, and the mirrored port locations. If I were to run TBI...I could run two 2bbls at the front and rear, four single bbls with one at each corner...or four small 2bbls placed at each corner. Any centrally placed throttle body (perpendicular to the crank centerline) would likely meet with fuel distribution issues.

Here's a picture of my heads and intake, as they were last run on Craig Pai's 329ci 8.6 second ASSC Mustang:



Once I get the intake in hand, and inspect the angle of the injector bungs...I'll decide if I'll have to go TBI or whether this intake will work for street based port injection.

Until then though...give me some options on different styles of single and 2bbl TBI throttle bodies .

Cris

[C.Anderson]

Well, I got my stuff today. Here's a few pictures and dimensions.

Intake manifold:









All I can say about the intake is it is incredibly cool. Runner length is 3.75", plenum opening dimensions are 2.7"x1.75", port opening dimensions are 2.188"x1.375". The curvature of the lower plenum is almost hemispherical, and is approximately 4" in diameter from runner to runner across the banks. The central port dividers ARE hemispherical (same tubing diameter as the lower plenum), and are 5" from port to port.







The size of the manifold and plenum...is difficult to describe. The thing is 8" tall from deck to top plate. The plenum is 11.25" wide, and 18" long. It is 2" deep at the center riser, and the deepest part of the plenum is 2.5" deep. To be honest, I think even wetflow would not be hugely compromised with this manifold, given proper carb placement.





The injector angle and placement is deceiving. The angle is virtually parallel to the intake face of the head. The center of the bung is 1.25" down from the plenum (on the runner roof of course), and its trajectory is 1.75" down from the plenum on the runner floor. The Bing is 2.125" up from the port, and the trajectory is approximately 2.25" from the port. Average runner length as I said is 3.75". The tip of the injector will sit approximately 3" from the runner floor.

Anyhow, I thought you guys might like more information on the manifold. All in all I'm pretty pleased. It LOOKS aggressive, but the injector angle isn't as bad as the original pictures indicated...and the plenum volume is much smaller than it seemed as well. I don't think this will do too badly on the street in port injection form, assuming modest throttle bodies.

I'm still open to induction suggestions though!!

Cris

[fury fan]

Ross Machine Racing has the drillbit and cheap bulk fuel rail.
http://www.rossmachineracing.com/injectortool.html

I found a quasi-similar pilot-tipped counterbore bit at McMaster.com for about $35, I don't remember the size but I do remember that it was metric.
http://www.mcmaster.com/#counterbores/=b1olz4

My first thought would be to figure out how to easily and reversibly plug the injector bungs. Maybe this would work?
http://www.mcmaster.com/#expansion-test-plugs/=b1onyy

Based on the port and runner configuration, I would research some GM 1-barrel TBs from 4cyl engines, and put one over each runner pair. Don't know if the injectors would be big enough, though. Another hassle would be supply and return connections to 4 TBs. If the 1-V TBs are like the 2-V GM TBs, the fittings angle down and out, the linkage hangs down a little, and might require a spacer plate to raise them 3/4" or so. then the MS2 still requires a resistor pack, for it can only handle 2 low-impedance injectors as-is. Then you need adjustable linkage to connect all 4.

Teh more I think about it, there's a lot of headache in putting multiple TBs on this intake for temporary purposes. I'd recommend you go straight to port-EFI, and consider perhaps a single large TB in the center for airflow.

[C.Anderson]

Ross Machine Racing has the drillbit and cheap bulk fuel rail.
http://www.rossmachineracing.com/injectortool.html

I found a quasi-similar pilot-tipped counterbore bit at McMaster.com for about $35, I don't remember the size but I do remember that it was metric.
http://www.mcmaster.com/#counterbores/=b1olz4

My first thought would be to figure out how to easily and reversibly plug the injector bungs. Maybe this would work?
http://www.mcmaster.com/#expansion-test-plugs/=b1onyy

Based on the port and runner configuration, I would research some GM 1-barrel TBs from 4cyl engines, and put one over each runner pair. Don't know if the injectors would be big enough, though. Another hassle would be supply and return connections to 4 TBs. If the 1-V TBs are like the 2-V GM TBs, the fittings angle down and out, the linkage hangs down a little, and might require a spacer plate to raise them 3/4" or so. then the MS2 still requires a resistor pack, for it can only handle 2 low-impedance injectors as-is. Then you need adjustable linkage to connect all 4.

Teh more I think about it, there's a lot of headache in putting multiple TBs on this intake for temporary purposes. I'd recommend you go straight to port-EFI, and consider perhaps a single large TB in the center for airflow.

Yep, a bit of this stuff is slightly problematic. The good news is that the rails came with it...so that's one down lol. On plugging the bungs...you read my mind. I've used test plugs in the past. Dorman makes steel body ones you can buy off the shelf at your local parts store.

On the temporary throttle bodies...I'm in agreement. What I may do...to save time...is run either two 500cfm 2bbl Holleys, or two 600cfm 4bbl Edelbrocks. That will get me by this summer on my existing fuel pump. As I can afford it over the summer/fall, I'll pick up the Megasquirt system for the winter. I'm going to stick with either 2 or 4 Mark VIII throttle bodies on the port system...both for originality, and because you can pick them up for literal pennies. The linkage is VERY simple. Air filters on the other hand...might be a bit more problematic lol. Not to mention hood clearance.

Cris