Siamesed intake ports, batch fire injectors in manifold?

[Lambo]

I have a pontiac 301 V8 turbo that has been undergoing a MS conversion for some time. It is a draw through setup, previously fueled by a CCC roch quadrajet. I have MS all wired in and running, ready to tune. I'm already finding out that I don't have near enough air flow, nor injector capacity.

I utilized a TBI off of a early 90s chevy 350. They only flow around 480 cfm, and the injectors I beleive are somewhere in the 50's for pph.

In stock form this engine only produced about 210 hp at 8-9lbs boost, with MS, a few other mods, and boost at 15psi, I expect to get around 300 at the crank, or maybe a little more. To do this effectively with 2 injectors, I'd need near 100pph injectors. There are options to improve this, other TBI units, ideally I'd find a 4 barrel TBI unit. All of which would still leave me with a draw through fuel setup.

One of the deterrents for "port" injection, is that the heads for the 301 have siamesed intake ports, and there is only one manifold that works with the short deck 301. So, down to the real question. The manifold that is on it has effectively two "runners", and there really isn't much to these runners. TPI with siamesed ports has been discussed many times, and the bottom line is you can't do it effectively, but I wonder if I put 4 injectors right in the manifold, as far from the ports as reasonably, but still aimed at an angle toward the port, would it work to run them in batch fire mode?

I figured I'd use something similar to this to install them. I have an extra manifold I can hack on:
https://www.DIYAutoTune.com/product/wel ... injectors/

Here is a picture to give you a visual of the intake. It is obviously single plane, and very basic. The stock tubo bolts directly to it:


If this can work, I'd just remove the draw through intake plenum all together and just fab something to mount a larger single plate throttle body to, maybe from an LS motor or something.

[Lambo]

A correction.... I said "two" runners, obviously there are 4 runners, for 8 cylinders.

[Matt Cramer]

I'm guessing putting a set of 455 heads on there and a sheet metal intake manifold isn't an option? I did a bit of searching, and found that TTA Performance makes a conversion gasket option for this, but there's currently no off the shelf manifold.

http://www.ttaperformance.com/cylinder- ... skets.html

This one is a bit of a challenge, as it appears that Pontiac's plan was to have the heat of the turbo setup vaporize the fuel to the point it can't drop out. Worse, the #5 and #7 cylinders share a single port and are right next to each other in the firing order. I can't even figure out a cam lobe swap that would remove this problem with an alternate firing order. You might be able to get around this if the injectors are far enough up the intake manifold, but this is one of the nastiest versions of the Siamese port problem I've ever seen.

[Lambo]

yeah, this engine is quite the bad step child.... I appreciate that you did you're own digging on this.

So, what you're saying is 5 would probably steal all of the fuel and 7 would run lean. Maybe I could build some sort of injector plate between the turbo and the intake so all fuel is squirted further up stream.

While the sheet metal intake sounds awesome... it is a bit restrictive financially . Also, I don't want to veer TOO far from what this engine is. If I can find a DIY way to get it done though, maybe. I've toyed with the idea of hacking up a cheaper pontiac tunnel ram, and affixing the runners to a new hand bent sheet metal plenum. That's pipe dream talk for now though. I DO have a buddy who's getting good with his tig welder, so, MAYBE.

If I want that far, shouldn't I consider just getting a complete 455... stroke it... leave rubber everywhere... and be really happy.

...but no, 301 owners are gluttons for pain, so we keep trying to make these short deck lemons run.

TTA performance has actually come up with a roller rockers, and a custom cam grind for this engine. That may be in my future. Within that same discussion there has been talk of a custom cam grind to change the firing order to that similar of an LS engine. More pie in the sky talk though. It hasn't been done yet.

I make look at other options. If I could just find a TBI unit that is reasonable with better injectors maybe that'll have to suffice. FAST sells their 2 injector unit with two 85 lb injectors included for around 700. You can buy that whole system with 4 injectors through for $900 now.