Mustang 200 EFI Conversion

Scuderia

Member
Nov 16, 2021
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Hi All

This summer I bought a 65 Coupe - clean and fairly original 6. Once I took ownership I kept running into carb issues. I never really got to enjoy it. Those 1 barrels are less than fun. So I decided to do a EFI swap as Holley makes an EFI setup for the Autolite 1100. I ordered the parts and they trickled in for months. This week the Sniper EFI finally showed up (ordered in June!). This is what I ordered for those interested.

fuel pump12-305375.00375.0011Holley
Fuel system526-9160.00160.0011Holley
Sniper550-552803.95803.9510Holley
Igniition Box556-151221.95221.9511Holley
Coil556-15242.0042.0011Holley
Distributor565-315268.00268.0011Holley


I'll document the process if anyone is interested. I just got the new Fuel pump in this passed weekend so the project is moving! Once this is done I want to do the front disc conversion as well. Im looking at the Wilwood and SSBC kits. Im going to leave it a 6 - maybe rebuild it with those Aussie heads/intake. Finding performance parts is rough for this motor. The vintage inlines guy seems pretty backed up.

If you have any tips or tricks I'm all ears. And as I said - I can post updates below.

Thanks!
PXL_20210602_134500829.MP.jpg
 
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Hi All

This summer I bought a 65 Coupe - clean and fairly original 6. Once I took ownership I kept running into carb issues. I never really got to enjoy it. Those 1 barrels are less than fun. So I decided to do a EFI swap as Holley makes an EFI setup for the Autolite 1100. I ordered the parts and they trickled in for months. This week the Sniper EFI finally showed up (ordered in June!). This is what I ordered for those interested.

fuel pump12-305375.00375.0011Holley
Fuel system526-9160.00160.0011Holley
Sniper550-552803.95803.9510Holley
Igniition Box556-151221.95221.9511Holley
Coil556-15242.0042.0011Holley
Distributor565-315268.00268.0011Holley


I'll document the process if anyone is interested. I just got the new Fuel pump in this passed weekend so the project is moving! Once this is done I want to do the front disc conversion as well. Im looking at the Wilwood and SSBC kits. Im going to leave it a 6 - maybe rebuild it with those Aussie heads/intake. Finding performance parts is rough for this motor. The vintage inlines guy seems pretty backed up.

If you have any tips or tricks I'm all ears. And as I said - I can post updates below.

Thanks!
PXL_20210602_134500829.MP.jpg
 
Screen Shot 2021-11-22 at 11.48.24 AM.png



I took an interesting pic of the inside of the tank - I was checking to see if there was rust but it looks almost brand new inside - thanks PO!

I also got the new fuel pump in - Pretty straight forward - the trick was getting the ring on at the end - that took a bit of time to line up right.

Screen Shot 2021-11-22 at 11.48.36 AM.png


Screen Shot 2021-11-22 at 11.49.43 AM.png
 
Maybe a new muffler and exhaust pipe while I'm here. These look.....worn - Any thoughts on what sounds good??

Screen Shot 2021-11-22 at 11.50.01 AM.png




I should clean up these wires too.


Screen Shot 2021-11-22 at 11.49.52 AM.png




Next I need to run the wires for the fuel pump and the fuel lines!

Screen Shot 2021-11-22 at 11.49.31 AM.png
 
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Does the Holley not use a return line for the pump? I guess I am just so used to running a return line since it allows a lot more flexibility in injectors and fuel pressure. Out of curiosity, what fuel pressure does the Holley use anyway? It can't be too high being TBI
 
Does the Holley not use a return line for the pump? I guess I am just so used to running a return line since it allows a lot more flexibility in injectors and fuel pressure. Out of curiosity, what fuel pressure does the Holley use anyway? It can't be too high being TBI
It doesn't - it's returnless - which made me nervous - but we will find out soon. I am hoping to get it fired up this month - it's just been so cold out I haven't wanted to be in the garage.

Injector isn't too big 100lb/hr 58.5psi
 
Update - then questions

So the fuel lines are in - it was weird using rubber lines, I hadn't done that in the past. Pretty straight forward and I ran them along where the metal lines were. Holley recommended this: Fuel lines

Fuel pump Wiring harness is in - relays mounted - I still need to make it pretty but it's in.

Fuel tank is in

Hyperspark distributor is in. - This was super easy - shockingly easy.

I need to buy a little cover for the mechanical fuel pump since I don't need that anymore. It does kinda look cool though so I may keep it to keep the motor looking like it did.

Questions -

The temp sensor for the EFI - I put it where the gauge temp sensor is - but that means my gauge sensor doesn't work. Anyone else have any ideas?

Any recommendations on where to pick up the ignition switch in the bay? I haven't found a great spot.

I need to mount the ignition box - it's pretty big. I thought about it on the back firewall but I would then run the fuel pump power right passed it. Will that be an issue?




Screen Shot 2022-03-07 at 3.16.42 PM.png
 
I got everything in yesterday and turned it over today.

When I turned the key nothing happened. no fuel pressure and when I checked with a multi-meter there wasn't anything to the pump. I had used the coil hot as the ignition source (since I moved the coil to the side and used a CD box that line was open)but the connection wasn't great. Once I found my mistake the fuel pump came alive and sprayed some gas all over. I had one bad fuel line connection that needed to be tightened and I didn't realize the return line wasn't plugged.

(Note: The return line is needed if using an out of tank fuel pump. Since I switched to the intake Holley pump I didn't need to plumb a return line. A 6an cap is all I needed)

Once it turned over it was super lumpy. I didn't program it in the panel first so I needed to set the carb, ignition and timing. I went with WOT of 34, and idle of 470 to start. Once I get it a bit more dialed in I will put up the numbers.

I turned it over again and it ran great. Smooth and pretty strong. it got up to temp and it went into Self-Learn mode.

I still need to wrap the wires running along the firewall to keep it neat and looking sharp.

Some overall notes - If you read the directions it's actually not too bad a job. Took me time as parts came in slowly and the bulk of things came in Nov. My garage isn't heated so I started in early march. It could have been done in a long weekend if I had ANY idea at all what I was doing.

The wiring took time. a lot of time. So just going through it and making sure you have the right connections is super important.

Making the spark plug wires sucked. What an annoying job that is. And I didn't realize I had too so that was a surprise. The MSD kit is good and gives you the job you need. It's just a tedious job.

They don't require a fuel pressure gauge but it's definitely worth it.

I went with Holley everything so it all matched well and was easy to work with.

Don't forget to cap the mechanical fuel pump hole!

I saw a bunch of things I want to upgrade now that I have been through every inch. Even the pic below - I need to clean up this engine bay.

Next comes the disc brake conversion!!!!!!


1653005262818.png
 
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Where did you mount the computer? The wiring is always the most interesting part of these conversions.
Where did you mount the computer? The wiring is always the most interesting part of these conversions.
I ran it through the firewall and it's tucked under the dashboard. I am still struggling with the right timing and settings across all of ignition and fueling. And there is a ton of wires - way way too many. So it's trying to keep them tight and neat.
 
I’m in the middle of my 302 swap from a 87 TBird with stock EFI and for sure, the wiring, where to put the components, etc is the most challenging/fun to me.

7723A926-8243-41D8-A831-2F813A248441.jpeg Power distribution and ECU to car harness interface
. 837BAFBF-25A7-417F-BF5A-13E581F3AA28.jpeg Firewall penetration of ECU harness (It’s hard to see).

I don’t see anything in the screen shots that scream power robbing. One thing, that battery voltage should be > 12 since it’s running, more like 12.7 VDC. You should use an independent meter to verify the battery voltage when the engine is running.

Since I don’t know, is the CFM of the new system lower than the stock carburetor? And did you change anything else beside unbolt carb and attach Holley system? But I have to say, looks very cool.
 
I’m in the middle of my 302 swap from a 87 TBird with stock EFI and for sure, the wiring, where to put the components, etc is the most challenging/fun to me.

7723A926-8243-41D8-A831-2F813A248441.jpeg Power distribution and ECU to car harness interface
. 837BAFBF-25A7-417F-BF5A-13E581F3AA28.jpeg Firewall penetration of ECU harness (It’s hard to see).

I don’t see anything in the screen shots that scream power robbing. One thing, that battery voltage should be > 12 since it’s running, more like 12.7 VDC. You should use an independent meter to verify the battery voltage when the engine is running.

Since I don’t know, is the CFM of the new system lower than the stock carburetor? And did you change anything else beside unbolt carb and attach Holley system? But I have to say, looks very cool.

The wiring is frustrating at times - and making it all look right is also very tricky - Thanks for the kind words on mine.

And yeah I did the Fuel pump, new fuel lines, electric distributor, new coil, CD Box (which is freaking huge, pic below).

I think my O2 sensor shook a bit loose since I was using the clamp. I ordered a new down pipe and am going to get someone to weld the bung to make it cleaner but this was the in between until I did it.

Also I saw a what looked like an 87 Tbird yesterday, he waved while I was trying to mess with the settings on this. It was all blacked out and looked pretty great!

Screen Shot 2022-06-01 at 11.30.15 AM.png
 
Yea, I was lucky to find an 87 TBird for a donor car, low mileage and I drove it on the trailer. Having a complete, running car, has made the swap process easier, but it’s still hard work, especially the ECU harness and creating a fuel system return line. I also relocated the battery to the trunk, so all of that additional complication, but I’m kinda proud I’m taking my time and learning so much by doing this. I suspect you’ll find your issue real soon, good luck. Steve
 
Yea, I was lucky to find an 87 TBird for a donor car, low mileage and I drove it on the trailer. Having a complete, running car, has made the swap process easier, but it’s still hard work, especially the ECU harness and creating a fuel system return line. I also relocated the battery to the trunk, so all of that additional complication, but I’m kinda proud I’m taking my time and learning so much by doing this. I suspect you’ll find your issue real soon, good luck. Steve
If you got pictures or a link to a project page lemme know - would love to look
 
Try this, it’s my Build Thread; I laugh, I cry, I learn stuff lol.

 
I got everything in yesterday and turned it over today.

When I turned the key nothing happened. no fuel pressure and when I checked with a multi-meter there wasn't anything to the pump. I had used the coil hot as the ignition source (since I moved the coil to the side and used a CD box that line was open)but the connection wasn't great. Once I found my mistake the fuel pump came alive and sprayed some gas all over. I had one bad fuel line connection that needed to be tightened and I didn't realize the return line wasn't plugged.

(Note: The return line is needed if using an out of tank fuel pump. Since I switched to the intake Holley pump I didn't need to plumb a return line. A 6an cap is all I needed)

Once it turned over it was super lumpy. I didn't program it in the panel first so I needed to set the carb, ignition and timing. I went with WOT of 34, and idle of 470 to start. Once I get it a bit more dialed in I will put up the numbers.

I turned it over again and it ran great. Smooth and pretty strong. it got up to temp and it went into Self-Learn mode.

I still need to wrap the wires running along the firewall to keep it neat and looking sharp.

Some overall notes - If you read the directions it's actually not too bad a job. Took me time as parts came in slowly and the bulk of things came in Nov. My garage isn't heated so I started in early march. It could have been done in a long weekend if I had ANY idea at all what I was doing.

The wiring took time. a lot of time. So just going through it and making sure you have the right connections is super important.

Making the spark plug wires sucked. What an annoying job that is. And I didn't realize I had too so that was a surprise. The MSD kit is good and gives you the job you need. It's just a tedious job.

They don't require a fuel pressure gauge but it's definitely worth it.

I went with Holley everything so it all matched well and was easy to work with.

Don't forget to cap the mechanical fuel pump hole!

I saw a bunch of things I want to upgrade now that I have been through every inch. Even the pic below - I need to clean up this engine bay.

Next comes the disc brake conversion!!!!!!


1653005262818.png
Heyo... I'm in the middle of this conversion myself, I've been using your post as my blueprint... Thank you Soo much. Pump, electrical, lines, distributor all went in today... I have everything but the TBI in house. (Still waiting on it.) I'm going to put the rest in just as you have in the pics... Did you run into any issues after driving for a while... Heat or water or anything??