I've seen some posts indicating this setup could work but I'm giving serious thought to trying it:

Holley 9901-101-1 intake: $270
Holley 9900-172 fuel rails $200 (less $ option?)
24lb. injectors $100+
Holley 4 bbl. tbi 700cfm (minus injector pod) (used for a throttle body) $75
GM 1227730 ecu, harness & sensors ~$80
Custom Prom $?

Could that work & get me to mpfi under $1000? Because I don't have the prom tools & skills I may substitute the Holley 950 ecm for the 7730- raising the cost from ~$850 to ~$1400 but I'm still well below $2300. (Accel Pro Ram comes in at $1700 but I don't see a lot of response to that setup) This is a conversion project for my daily driven '78 Malibu which currently has a carbed 350 getting ~10mpg.

Thoughts and input welcome,
Chris

 

I talked to a guy at Holley tech & he said it would be fine to use tha 4 bbl tbi as a throttle body. I also asked if there were dividers in the runners of the 950 intake. He said no because it was designed strictly as a FI intake. I'm not sure how it would work if I ever wanted to campare the performance of the FI to a carb.

Accels Pro Ram intake does have dividers (see them on this auction: http://cgi.ebay.com/ebaymotors/ws/eB...tem=1812123808) and the catalog says it can be used for FI or carb (assuming you plug the injector bosses of course). Accel's intake with rails is $410 vs. Holleys $470. Things get a bit confusing when you look at bare intake prices; Holley: $270, Accel: $360.

So I may use the Accel intake with a Holley conversion package such as 950-101, 950-109 or 950-115.

Or I could fabricate my own fuel rails and use Holley's intake, but I'm leary of not having dividers should I want to swap to a carb (temporarilly - for racing perhaps).

Anyone try anything like this?
Chris

 

You mean plenum divider? The Holley and Accel both use single plane style intake with open plenums. They'd both work with a carb.

I use a 900 CFM TBI Holley throttle body on my car (with MPFI, just use it for an air valve). Works great.

If you have access to a bridgeport convert an existing manifold with injector bungs and rails.

 

Dividers in the runners not the plenum. Attached pic is of the Accel intake, the Holley tech said there aren't dividers in the runners of the Holley intake. Via internet searches I found out Brodix makes the Accel FI intake.

Please tell me more about your FI swap (pictures?). Did you use a GM ecm or aftermarket? I've bought the 700cfm tbi (minus injectors) so I have a throttle body now. That is a good idea about a intake conversion. I bet it would be less expensive.

Thanks for your input,
Chris

 

Sure the Holley EFI intakes have dividers in the runners. Don't have a clue why you were told they don't.

I use the Holley Commander 950 ECU. Don't have any pics. Car is a street Nova that runs high 11's with a 388 SB.

 

OK Doug I just realized who you are , thanks for the response.

So you made your own intake? Which intake did you use? I thought of a used Torker II as an inexpensive option - it looks like they just converted that intake to accept a 2V throttle body when they designed the performer and tbi conversion mpfi systems. Do the higher rpm style tall single plane intakes (Victor, etc) take away throttle response and low end torque when used with FI?

My stepfather can weld aluminum so we could weld the bungs but he doesn't have a bridgeport. He does have a drill press, with a fixure I imagine we could figure out a way to drill the holes at the correct angle consistently. I was also thinking I could use the stock tpi fuel rails if I mounted the bungs - but maybe the tpi fuel rails don't mount the injectors at the best angle? Did you make your own rails?

Lots of questions I know- thanks,
Chris

 

I used a Holley 300-110 which is the strip dominator redesigned by Keith Dorton. It is overkill for my engine as far as flow.

I used a bridgeport and put the bungs in. I epoxy them with JB weld and never have a problem, but welding is obviously better. My first intake I machined my own rails but last time I did it I used fully machined Holley rails (from their SBC MPFI systems) and made the injector centers on the intake the same as the rail. Pretty economical way to do it.

I'd be a little leary about a drill press. You need to get the bungs in line and in the same location as the rails. A machine shop should do this for pretty cheap.

I don't think there is any problem using a big single plane vs a smaller single plane at all with EFI.

I mount my injectors straight up and down with no problems. Some people actually tilt them out for rail to throttle body clearance and say they have no problem. It's not like the fuel sprays out and sits there long even on a batch fire.

The main problem I have is rail to throttle body arm clearance while trying to maintain the stock hood. I did that with the 300-110 intake, 4 bbl tbi for an air valve and careful placement of the rails.

No problem answering questions.

 

Doug, what is a bridgeport?

Where could one get the holley rails you refer to?

Where could I purchase the Commander ECU seperate, and how much?