Engine GT40 Heads + Cam Help

Tancalhan

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Apr 11, 2020
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Frederic WI
So I’m about ready to start modding my new to me 89 GT. So far I’ve only put 3.27’s in it, shorty’s, off-road h pipe, flowmaster American thunder catback, and that’s about it “performance wise” Last year I got some gt40 heads with the trickflow valve spring kit, cobra 1.7 RR’s, and a new in box b303 cam, I paid around 200 for it all and sent the heads out to get the spring kit installed and checked, they did a valve job and replaced the guides, among some other stuff. I want to put all this on my 89, I also have an explorer upper/lower I got from Junkyard Doggs, if you know of him or not. My questions are - will I need a bigger fuel pump and 24# injectors, is it necessary to get a chip tune from like SCT, or will the A9L adjust itself accordingly?, I’m new to the EFI foxes, only ever dealt with/built carb’d ones. The car only has 62K miles but I’ve always wanted to do the “almighty b cam” and gt40’s, and I want to modify this car the “period correct” way, in a sense. I’m fine leaving it almost bone stock but I just want a little more power for cruising. The 3.27’s helped a lot, I didn’t go 3.55’s for 3.73’s because I drive on the highway/freeway atleast 6+ hours a week. TLDR: do I need bigger injectors and do I need a tune? Local dyno shop only charges $150 to mount up and $100 for 3 pulls + final results, I’m not sure if they do custom tunes or what not. Thanks.
0329F5BB-5B81-4BAE-BAF0-965B221BA281.jpeg
 
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Mustang5L5

Put lubricant all over the balls
Mod Dude
Feb 18, 2001
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What fuel pump is in there now?

Most likely you do not need a new fuel pump or injectors. You might be maxing out your injector duty cycle, and might run lean at the top of a 3-gear WOT run, but until you put the combo together you won't really know.

24# injectors would allow you to be closer to the 80% duty cycle rate, and if your pump is an original 88lph pump, a 110lph or 155lph pump would work for you. I'm not one to recommend putting in a huge pump regardless of the fuel demand needs because it can over circulate the fuel (which can cause boiling) and increasing the flow rate in stock lines can lead to fuel pressure creeping up a little higher than desired depending on the orifice size in the regulator. If this is a "forever combo" than i'd stick to 155 max.

The A9L might be able to handle this combo without tuning. You'll need a "calibrated" maf for the 24's however. But i've seen your exact combo done a bunch of times, with no tuning, and it runs great. The B303 cam tends to like higher RPM. Over 3000 it pulls.
 

General karthief

wonder how much it would cost to ship you a pair
Mod Dude
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My experience with the 'B cam' was a bucking problem at low rpms, didn't seem to like to schlep along in low gear at 1500 rpms like moving through a parking lot or slow traffic other than that ran great,
I think with 3.27 gear it should be fun to drive.
 
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Tancalhan

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Apr 11, 2020
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Frederic WI
Ok, thanks for the information. Yes it is the original fuel pump, from what I’ve been told it’s Ok to use the 19#, but they’ll be maxed on their duty cycle. Even tho they’re low mileage, they’re still 32 years old, so I think I’ll run the 19# to start and if I have issues with the A/F, I’ll switch to 24# and most likely change the fuel pump. But I do know the stock pump is a ticking time bomb, every single fox I’ve owned has needed a fuel pump at one point in its lifetime.
 

KRUISR

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Apr 16, 2015
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My combo is similar. I have a Crower 15512 (2400-5800 operating range) instead of the B-cam. I ran Explorer 19s until just recently I switched in some 24s. In all iterations of my combo so far I just used a C&L MAF with appropriate flow tube (calibration tube), no other tuning (first had a 73 with 19s, then a 76 with 19s and now 76 with 24s). I only switched to 24s because at higher RPM 4500+, I was starting to see 90-95% duty cycle on the injectors. Air/Fuel Ratios were great still but it was a high duty cycle.

I have a fuel pump from a Lincoln LS (factory 340 lph) and adjustable FPR.
 

limp

wrap a little cheese around it and its a done
Oct 4, 2020
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My experience with the 'B cam' was a bucking problem at low rpms, didn't seem to like to schlep along in low gear at 1500 rpms like moving through a parking lot or slow traffic other than that ran great,
That would have been perfect when we were 18....LOL
 

Tancalhan

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Apr 11, 2020
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Frederic WI
Ok, I appreciate it. Is it necessary to upgrade my throttle body? It has a BBK fenderwell cold-air as well, stock MAF. I know eventually when I switch to 24#, I’ll have to get the calibrated MAF. Another 400 or so isn’t in the budget yet for said TB, MAF, and injector upgrades
 

Mustang5L5

Put lubricant all over the balls
Mod Dude
Feb 18, 2001
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find an early explorer throttle body off eBay or junkyard and convert it. 65mm will be plenty for what you are doing.

but you can run the stocker in the meantime.
 

Tancalhan

Member
Apr 11, 2020
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Frederic WI
One more question - my state (WI) doesn’t do emission testing. My explorer intake is the early internal EGR one, is it worth going thru the hassle to run EGR, or just delete it? I’ve been told deleting it causes issues with the ECU and negatively affects gas mileage.
 

Mustang5L5

Put lubricant all over the balls
Mod Dude
Feb 18, 2001
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If your goal is to avoid doing any sort of ECU tuning then just retain it. Folks like to think it adds 50HP by deleting it. It doesn’t.

You’ll need to run an EGR spacer anyway to mount the throttle cable bracket and for proper spacing for air induction.
 

Tancalhan

Member
Apr 11, 2020
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Frederic WI
If your goal is to avoid doing any sort of ECU tuning then just retain it. Folks like to think it adds 50HP by deleting it. It doesn’t.

You’ll need to run an EGR spacer anyway to mount the throttle cable bracket and for proper spacing for air induction.
Perfect. Thanks
 

mikestang63

SN Certified Technician
Aug 27, 2012
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yes on the fuel pump
no on injectors
forget the B cam and just install 1.7 rockers, you will get about the same lift with better manners and driveability
if you want to put a cam in do it right and put an N41 in it
no tune neede
get a 70 MM MAF from a 94 to 95 gt and the 65mm Throttle Body off an explorer and do the conversion to make it work
 
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Tancalhan

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Apr 11, 2020
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Frederic WI
I don’t want to hear “throw away the b cam” I basically got it new in box for free, it’s what I want to run. I’m asking for advice on my current setup and plans. Thanks for the other advice tho. I appreciate it
 

Willybill32

But at least it's tight!
Jul 16, 2019
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My experience with the 'B cam' was a bucking problem at low rpms, didn't seem to like to schlep along in low gear at 1500 rpms like moving through a parking lot or slow traffic other than that ran great,
I think with 3.27 gear it should be fun to drive.
@General karthief: I have the bucking issue on my ‘86 with the E303 cam. My tuner says it’s likely the cam…any solution?
 

General karthief

wonder how much it would cost to ship you a pair
Mod Dude
Aug 25, 2016
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@General karthief: I have the bucking issue on my ‘86 with the E303 cam. My tuner says it’s likely the cam…any solution?
Not really, my understanding is the computer don't like low rpm overlap in the cam, it can be 'tuned' out but I think it takes something like an aftermarket ecu.
You will find, as you already know with the 86 and E cam, you just have to avoid the low rpm schlepping around.
Mine got so bad that I beat up the u joints really bad. It's hard on the trans, clutch, rear end gears, and the engine itself.
The stock cam and 1.7 rockers is really some good advice along with the N41 cam.
One could live with the B cam I suppose, they sound soooo cool at idle.
Burple burple burple
Another thing to keep in mind is that cam works between 2500 and 6000+ rpms so that is a narrow window, and you loose some low end grunt that is important on the street.
JMO
 
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Willybill32

But at least it's tight!
Jul 16, 2019
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Not really, my understanding is the computer don't like low rpm overlap in the cam, it can be 'tuned' out but I think it takes something like an aftermarket ecu.
You will find, as you already know with the 86 and E cam, you just have to avoid the low rpm schlepping around.
Mine got so bad that I beat up the u joints really bad. It's hard on the trans, clutch, rear end gears, and the engine itself.
The stock cam and 1.7 rockers is really some good advice along with the N41 cam.
One could live with the B cam I suppose, they sound soooo cool at idle.
Burple burple burple
Another thing to keep in mind is that cam works between 2500 and 6000+ rpms so that is a narrow window, and you loose some low end grunt that is important on the street.
JMO
Do you think the N41 cam is a help? I love the sound of my ‘86 with the E cam, but it’s not a lot of fun driving in town and parking lots, as you already know.
 

mikestang63

SN Certified Technician
Aug 27, 2012
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Do you think the N41 cam is a help? I love the sound of my ‘86 with the E cam, but it’s not a lot of fun driving in town and parking lots, as you already know.
your 86 has flat top pistons with no valve reliefs. You will need to check for PTV clearance with any cam that has a longer than stock duration. I csnnot remember off the top of my head but there are cams that will work with those pistons. If you had TW heads that would allow for a more aggressive cam vs. the stock style inline valve heads like GT40, AFR, etc. IMO the best option is to reach out to Ed Curtis and have him grind you a custom cam for your specs. It may cost a little more, but you will be smiling every time you drive it thanks to better manners and power.