What fuel pump for 42lb injectors?

Daryl · Feb 27, 2025

I’m branching off of my earlier thread “fuel rail and vacuum help” to ask about injectors and fuel pumps. A little refresher about my motor and driveline: 347 stroker; Scat rotating assembly; Crane E-cam; AFR 165 heads; BBK 75mm throttle body; fender well cold air intake. Currently running Accel 24lb injectors; stock fuel pump/fuel rails/ fuel pressure regulator/ fuel filter. Stock gas tank. Tremec TKX 5-speed with Ford Performance 3.55 rear gears.

Keeping in mind that I live in CA and have to pass smog every other year, if I go to 42lb injectors, what brands and type? What fuel pump, brands and flow? Different fuel filter needed or recommended? And what about fuel rails? Is stock ok, or ???

Remember: I live in CA so gotta be creative &/or sneaky smart to pull this off ;-)
Upgrades, if visible @ smog inspection, have to appear stock.

Thanks everyone!

duh09 · Feb 27, 2025

Ford 42# is what I'd be hunting for. EV1 style so will physically be identical to your 24# besides a different color top. Like these:

https://lmr.com/item/LTP-CM5256/motorcraft-f-150-svt-lightning-fuel-injectors-ev1-42?utm_source=google&utm_medium=cpc&adpos=&scid=scplp&sc_intid=&gad_source=1&gclid=CjwKCAiAt4C-BhBcEiwA8Kp0CeZUGPnlZbP-QS6VrFacQOUPW4Dt5VBekZJvRbEyrK0tDaMjOHz4pxoCupkQAvD_BwE

I believe a Walbro 255lph would likely fuel them enough. Like this: https://lmr.com/item/LRS-9350D-K/1986-97-Mustang-Walbro-255-Lhp-High-Pressure-Fuel-Pump-Kit

No other changes needed besides an update to the tune.

Daryl · Feb 27, 2025

Is Walbro a good/reliable product? Or is it kind of middle of the road?

duh09 · Feb 27, 2025

I have had a Walbro / TI Automotive in almost every car build I've put together. The new fuel pump sitting in the new hangar for my car is another Walbro/TI E85.

95opal · Mar 1, 2025

Daryl said:
Is Walbro a good/reliable product? Or is it kind of middle of the road?

Walbro makes very good pumps.
Just a side note. A gt40 explorer intake would help you out and it's carb legal. Might want to add that to your list before you go back in for a dyno. Just a thought.

duh09 · Mar 1, 2025

95opal said:
Walbro makes very good pumps.
Just a side note. A gt40 explorer intake would help you out and it's carb legal. Might want to add that to your list before you go back in for a dyno. Just a thought.

His car is a Cobra, so should be covered there.

Daryl · Mar 1, 2025

95opal said:
Walbro makes very good pumps.
Just a side note. A gt40 explorer intake would help you out and it's carb legal. Might want to add that to your list before you go back in for a dyno. Just a thought.

Thanks for the tip! What year(s) Explorer/GT40 intake? Estimated price? Any ancillaries needed or straight swap?

Daryl · Mar 1, 2025

Google Product Result

Like this? And then clean it inside and out? Maybe ceramic coated?

ttocs · Mar 1, 2025

cobra's already have a version of that intake on them unless you are doing the fox body conversion as the one shown is. If so you will need the throat/bend as well as a new TB cable

Daryl · Mar 1, 2025

Huh. Interesting. If there’s not much difference I’m thinking “what’s the point?” Just the injectors and pump then…

ttocs · Mar 1, 2025

he was assuming you had the stock gt intake and there are some gains to be made switching its intake for a gt40/cobra intake, but in your case it will not do anything unless someone mentions that it effects the throttle control with the fox body version. I hear people say it makes it quicker to react but I think they are justifying the work done to it.

Daryl · Mar 15, 2025

I’m learning that there’s a lot more to know before pulling the trigger here!

What combo of pump & injectors? Deatschwerks? Walbro? Bosch? Accel? Internal or external pump? High or low impedance injectors? Stock fuel rail ok? Stock fuel filter ok? And who’s buried in Grants tomb?! And what is the cube root of Pi r squared?! ROFLMFAO!

( sorry, couldn’t resist adding a little levity)

P.S.- if Walbro, WHICH 255lph pump? They show 3 on their website and I don’t know the difference!

Musturd · Mar 16, 2025

if you’re on a stock ecu and not doing a blower there’s no need to go to 42’s the 24’s you have are more then enough for your combo

ttocs · Mar 16, 2025

I thought his tuner told him he was maxing out the 24s but I get people confused.

Daryl · Mar 16, 2025

ttocs said:
I thought his tuner told him he was maxing out the 24s but I get people confused.

Yes, he said I was running lean basically across the entire band. I believe what initiated him mentioning it was the low hp # given my setup.

I do have a Vortec Supercharger gnawing at me in the back of my head though ;-)
SC+42lb’rs+255lph pump+a retune should get me pretty much maxed out for a CA car that will still pass smog.

Are the 3.55 rear gears that I have good for my dreamscape?!

Daryl · Mar 16, 2025

These???

Musturd · Mar 16, 2025

People have made 350whp with 24’s and not went lean . I find that strange your tooner said it wouldn’t keep up . There’s no way that combo makes near that being smog legal .