Author Topic: 426 Hemi EFI Build Thread  (Read 545 times)

Offline MopSquad

  • Jr. Member
  • **
  • Posts: 167
426 Hemi EFI Build Thread
« on: April 11, 2017 - 07:23:24 pm »
Hello all!  I'm starting an EFI conversion on my 426 Hemi Cuda.  I've amassed some parts and will be documenting the whole process on here from the engine bay work to the complete fuel system.  This is not a bolt-in conversion and requires some modifications, ingenuity and most of all, a good supply of cash LOL.  I've searched and taken ideas from other members on this forum and worked with Rich at fastmanefi for some of the supplies, computer and programming

Here is the parts list purchased:

Intake manifold:  Edelbrock 75245 EFI Dual TB
Throttle Bodies:  Holley 112-588 (2)
Fuel Rails: Edelbrock EDL-3660
Injectors:  42lb Delphi

To be purchased:

Computer:  Holley HP
Distributor: Holley 565-103
Ignition: MSD 6AL
Fuel pressure regulator: Aeromotive 13129
Return line: Stock steel piggy backing the other stock line
Tank and pump: Tanks inc EFI E-body
Various fittings and lines

« Last Edit: April 26, 2017 - 08:38:17 pm by MopSquad »




Offline MopSquad

  • Jr. Member
  • **
  • Posts: 167
Re: 426 EFI Hemi Build Thread
« Reply #1 on: April 11, 2017 - 08:14:50 pm »
Test fitting baseplate to intake and throttle bodies.  The good news is that the Edelbrock 75245 intake is stock height and spacing.  Thats where it ends LOL.  The Carter AFB's have a smaller base circle then the typical 5 1/4" 4150 style carbs and TB's.  Also, the rear TB idle motor hits the shaker baseplate.  So, I will be putting in 1/2" spacers to raise the TB's (as they are about 1" shorter in ht. than the AFB's and possibly a 1" spacer ring on top of the TB's to clear the idle motor and possibly work to seat against the shaker baseplate.  If there is no decrease in the air inlet, I may not have to cut the shaker baseplate opening to accommodate the bigger opening of the TB.



« Last Edit: April 19, 2017 - 02:20:15 pm by MopSquad »

Offline Flatdad

  • Jr. Member
  • **
  • Posts: 42
Re: 426 EFI Hemi Build Thread
« Reply #2 on: April 12, 2017 - 11:20:42 am »
The stinger fiberglass shaker base 1121BP is listed at $125 on AAR Fiberglass's website. The air-grabber style one that I used did NOT come with the holes cut in it, so they can be modified to suit your application.

It might be a cheap alternative if you don't want to cut up your steel plate.

I forget where I ordered it but the final cost after shipping it was exactly $170.82

Watching your thread with interest, cool project!

(P.S. I also had to make spacers, and cut up a couple plastic funnels from a farm store to get a tapered inlet at the right carb throat diameter. Cost of the funnels was about $4 each.)
'70 Road Runner-B7 383 Auto, now with more cubes
'97 Ram 1500 Sport 4x4-Bright Red 318 magnum
'67 Belvedere II-Dark Blue 318 Auto, now owned by my brother
'73 Challenger Rallye-B5 318 Auto, had a 360 in it, SOLD :(
'42 Harley Davidson 42WLA-U.S. army green 45ci flathead
'71 Challenger R/T-B5 383 Auto, now 400 powered and rusty!
'86 W100-Yellow 318-2bbl 4x4 4spd, off road toy


Offline MopSquad

  • Jr. Member
  • **
  • Posts: 167
Re: 426 EFI Hemi Build Thread
« Reply #3 on: April 12, 2017 - 12:27:14 pm »
The stinger fiberglass shaker base 1121BP is listed at $125 on AAR Fiberglass's website. The air-grabber style one that I used did NOT come with the holes cut in it, so they can be modified to suit your application.

It might be a cheap alternative if you don't want to cut up your steel plate.

I forget where I ordered it but the final cost after shipping it was exactly $170.82

Watching your thread with interest, cool project!

(P.S. I also had to make spacers, and cut up a couple plastic funnels from a farm store to get a tapered inlet at the right carb throat diameter. Cost of the funnels was about $4 each.)


Cool!  Thx for the ideas!

Offline gyman98

  • Jr. Member
  • **
  • Posts: 182
Re: 426 EFI Hemi Build Thread
« Reply #4 on: April 12, 2017 - 04:04:04 pm »
Sub'd for updates!  Did the similar project to mine last fall, excited to get out and drive it now
1970 hemicuda convertible clone 426/727 3.23 8 3/4 suregrip

Offline MopSquad

  • Jr. Member
  • **
  • Posts: 167
Re: 426 EFI Hemi Build Thread
« Reply #5 on: April 12, 2017 - 05:34:47 pm »
Sub'd for updates!  Did the similar project to mine last fall, excited to get out and drive it now

Do you have a thread I could check out?  What was the foundation? Intake, TB, computer.  Was it a shaker?

TIA

Offline gyman98

  • Jr. Member
  • **
  • Posts: 182
Re: 426 EFI Hemi Build Thread
« Reply #6 on: April 12, 2017 - 07:00:07 pm »
I didn't do a thread on it but I used the fitech dual quad set up with the sump. The intake is the factory mopar piece.  The biggest challenge was getting the shaker base to fit properly. 




1970 hemicuda convertible clone 426/727 3.23 8 3/4 suregrip

Offline xtopfuel

  • Jr. Member
  • **
  • Posts: 256
Re: 426 EFI Hemi Build Thread
« Reply #7 on: April 12, 2017 - 08:29:11 pm »
Good stuff

Offline MopSquad

  • Jr. Member
  • **
  • Posts: 167
Re: 426 EFI Hemi Build Thread
« Reply #8 on: April 12, 2017 - 08:42:54 pm »
I didn't do a thread on it but I used the fitech dual quad set up with the sump. The intake is the factory mopar piece.  The biggest challenge was getting the shaker base to fit properly. 




Cool, I saw that you kept the shaker AFB diameter opening and had spacers. That's ultimately what I want to do.  Hope that there is no restriction in air flow.

Offline gyman98

  • Jr. Member
  • **
  • Posts: 182
Re: 426 EFI Hemi Build Thread
« Reply #9 on: April 12, 2017 - 11:01:25 pm »
I think with the dual quads there isn't going to be a airflow restriction issue.  It worked with the carters and proper A/F ratio is the same whether it's carb'd or EFI
1970 hemicuda convertible clone 426/727 3.23 8 3/4 suregrip

Offline MopSquad

  • Jr. Member
  • **
  • Posts: 167
Re: 426 EFI Hemi Build Thread
« Reply #10 on: April 15, 2017 - 10:21:53 pm »
Here's a few more shots and an update.   The stock distance between the floor of the intake and the flush top of the carter AFB carbs is 8 1/8".  I placed 1" ring spacers on top of the Holley TBs.  the measurement is approx 8.42".  This was needed for clearance of the idle motor on the TB and the fuel rail hose in the front. At a difference of .295" (.42-.125), hopefully the shaker bubble will still fit. I won't know until the intake is on the motor.  I can have the the ring spacers milled down but then I'll have to cut into the baseplate to clear the rear idle motor.

Minor bit, the carters use a 1/4" center stud and the Holley TBs use a 5/16" stud.  The shaker baseplate holes are big enough to coax a 5/16 bolt thru.

Spacer part number:  Keyser    100-68827-10
« Last Edit: April 18, 2017 - 01:04:45 pm by MopSquad »

Offline MopSquad

  • Jr. Member
  • **
  • Posts: 167
Re: 426 EFI Hemi Build Thread
« Reply #11 on: April 19, 2017 - 11:18:23 am »
Another update.  Pics of the shaker installed in the stock configuration to examine the space remaining.  With another .29" needed in height for the EFI setup, it may fit.  I may mill down the spacers .125" and percuss the baseplate slightly for a little wiggle room.

« Last Edit: April 19, 2017 - 11:45:20 am by MopSquad »

Offline MopSquad

  • Jr. Member
  • **
  • Posts: 167
Re: 426 Hemi EFI Build Thread
« Reply #12 on: August 30, 2017 - 02:04:42 pm »
Been a very hot summer here in the desert and tough to do any work.  A quick update, painted the Edelbrock intake to match the motor.  Have to modify the front TB next to block off all IAC holes.  The IAC runs off the rear TB.  I'll probably have Rich at fastmanefi.com do the TB mod.