If you want to go F.I. and you have a Holley carb now. Then a 4 barrel TB seems the cheapest way. They are $370 new from Jegs. https://www.jegs.com/i/Holley/510/112-588/10002/-1
That's cheaper than a new 48 IDA plus you have to buy a manifold for the weber. The cost difference between the Holley TB and the Weber +manifold could go toward your Megasquirt.

or $160 on Ebay (plus the cost of the TPS, IAT, IAC).

https://www.ebay.com/itm/1200-Cfm-4-...8AAOSwSQFaAgoz

I was looking to pay a bit more for the Black version though since it looks so good!

https://www.ebay.com/itm/Speedmaster...MAAOSw7kVbCkhp

Or stick a TPS on a dead Holley 3310, which was a really common carb. A dab of weld in the right spot will give you mechanical 1:1 secondary operaton.

I really like this thread. Make good NA power (for an NA) on the cheap!

Always wanted to have a 4150 style throttle body on a RB intake honestly. But I'm not big of a EFI n00b :(.

Keep up the cool beans!

I'm seriously considering buying the RB 4-barrel intake and getting the holley efi 4150 throttle body. I wanted to build a custom intake to mount 4x Ducati ITBs I bought cheap off ebay but with the new ST6 and ST5 rules for NASA next year I think it's time I build the FC for wheel to wheel racing. Making power isn't going to be the problem. Quite the opposite with the full bridge t2 setup I have in her now. However, the simplicity of the Holley setup is very enticing...

I agree. It's so simple it seems! Easy plumbing, everything can be ready and fairly bolt on.

Let me know if you go that route, I'm having some pennies to see what I can do (I almost went carb, talking with DIY autotune and Banzai racing about an EMS).

How would one handle cold start idle enrichment? Could an IAC be fitted to one of the aforementioned throttle bodies? Could the software in the Megasquirt be used do it?

The Holley EFI TB comes with an idle air control motor already installed. I would just wire it to the megasquirt and double check the voltage it needs to see to operate correctly. Should be really simple and maybe my full bridge would actually idle below 1300! #RaceCarProblems

I've done some pretty extensive testing for potential e-prod setups and have actually had the displeasure of re-configuring one of Paul Yaw's FI setups (he's got some other cool gear but I think he took this car/customer for a bit of a ride). Long story short the best option we found has been RB 6 port manifolds and some sort of IDA - or if you're feeling froggy a 52 Berg - for fuel and some sort of ECU for ignition control (this particular build ran a stupid M2R so your megasquirt will be a otay). I don't think it's my place to out a customers end results but I will say it made significantly more power than Paul's 210whp when finshed.

Yeah I'm definitely worried once I get the ms3 pro evo, FFE trigger kit with ls coils, long primary exhaust, 4-port RB 4150 intake, and Holley EFI TB installed that it's going to make way too much power to fit into ST6 or ST5.... Can you say more about what the original FI setup was that you removed that made 210 whp?

Thanks! I was referring to the cheaper TB's that BlueTII posted. I should have been clearer. I looked at the pics in the ebay ad and I don't see an AIC or place to put one. I guess this is one reason the Holly and others are more expensive.

I never dyno'd the setup that Paul Yaw put on the car, just what we retrofitted on after the customer wanted more power. Remember though this was in E production so we were forced to use the entire EFI manifold with its weird turn-backs etc and for whatever reason it was a lame M2R setup. What we ended up with was a modified RB intake and a 52 Berg and 48mm venturis (May have been 46, its' been a while though). It was pretty night and day according to the driver.

The Procomp Electronics "Speedmaster" PCE138.1002 throttle bodies have provision for 1990 Ford Mustang TPS sensor and 1995 Chevy Impala IAC valve.

IAC goes here
https://cimg6.ibsrv.net/gimg/www.rx7...21c7f7ee10.jpg

nah, too expensive just buy it from me it makes very nice sound and if you ever wanted to turbo it, can also has a clean look and light weight :P >> https://www.rx7club.com/race-parts-o...weber-1128831/

I made 205HP on a 6port NA using a TII intake ...pump gas , full exhaust Adaptronic ECU

i wonder how much you would make on an s4 or s5 intake.