Hey guys,

With motors between 400 and 450 cubic inches (small block)
Which aftermarket fuel injection would be best suited? I have never seen any numbers on max displacement for any given vender.
Looking for power, drivability, and emissions legal (if that’s possible)
Would a carb be a better choice?
I want a large displacement small block for street cruzing.

 

Dont know bout a max displacement for a after market fuel system, bigger injectors and an ecm tune? personaly i like havin a nice fuel hoggin 4 barrel sittin on top but then again thats my opinion

 

The SuperRam is finicky to install but is good for up to 1000 CFM. I belive the Mini Ram is close to the same. Any of the Non standard TPI systems are designed to run larger CID. Factory stuff or Even factory stuff replaced with bigger stuff eg. ASM Runners arent going to do the trick. The biggest bottle neck in TPI isnt the runners as everyone likes to point to but the factory Base intake plate. I have seen numbers for flow to prove this. I will try to look them up to back my statements.

 

If you just want somthing "large" to kick butt on the street, a S/R, would be a good choice if emissions are a must. When you decide to get every ounce of power at the track, pick a manifold that is better suited for the additional airflow.

 

so, Mr. Dewynter:

does using the Edelbrock TPI base help out? if so, by how much? just wondering, since I have a couple of 400 blocks laying around and contemplating a TPI 406 (since I've invested so much effort & acquired knowledge in TPI), but concerned about exactly these type of bottlenecks.

 

I guess I'm looking to hear from people that have dynoed their 383+ cubic inch motors. I have a feeling that the TPI type intakes physically can't flow enough air to support large cubic inches.
Does anyone have a supercharged 383+ cubic inch motors? with some typ of TPI?

 

If you're only looking for street cruising, I would simply utilize the stock TPI system for now, albeit, heavily ported out. Of course, the potential of the additional cubic inches will not yet be realized though, but you can always swap to a much better intake manifold, afterward.

Bigger injectors, along with the right tune to optimize performance, and you'll be absolutely fine. Again though, the stock TPI unit is only temporary, just until you have all of the accompanying bugs, that always seem to come about when swapping to bigger cubed engines, worked out.

 

Sorry was gone for the weekend. Now onto your question, I'm currently at work and I dont have the flow chart, but tonight I will go home and retive it. I know that stock its only 10-13% increase in flow, but the edelbrock base can be ported, as another company uses the same casting, but cnc ported. After porting the runners will become the choke point. The throttlebody in stock form (48mm x2) is good for 620 CFM or close. The 58 can flow close to 1000 CFM but can cause a los of velocity in the plenum and actually cause problems. Unless you are running really big cubes the 52-54 is more than good and still retains the velocity. An inherint problem with TPI is that the front 4 cylinders get more air than tha rear 4 so you can get a lean/rich problem due to the design of the intake. The super RAM and other aftermarket intakes dont suffer from this as bad due to the larger Plenum Area.

 

Dewynter:
thanks for the answer. I ported the Edelbrock base somewhat just to clean up the machining transition to the as-cast surfaces. am using SLP runners, 52mm TB, and ported plenum. I'm still tuning the fuel curve though.