Hello all I am a new owner of a '84 F150 4x4 with the stock 4.9L 300 and a 4speed manual transmission, I'm looking to replace the intake manifold and carb along with swapping in a 5 speed transmission. any advice/input is very much appreciated.

- I'm unsure weather a 2 brl or 4 brl is better and with what manifolds/carb combo produces the best performance and reliability?

-what cfm is most compatible with the truck?

-and which (if any) 5 speed transmission would be the easiest to swap in?

this truck is my daily driver as well as my hunting/fishing rig. I'm looking to improve my over all performance without compromising it's drive ability or gas mileage to much. Any further suggestions on parts or resources again would be much appreciated.

-James-

 

Welcome to FTE!
You say the truck is an 84 with the mighty 6. This could have either style carb/ignition setup on it. If it has the non-feedback system, swapping the intake/carb is much simpler than on a feedback (computer controled) system.
First thing, find out if it's feedback or not. Carb have 2-3 wires going to it, or 50 bazzillion (slight overstatement)? Distributor have a vacuum advance on it, or big box with several wires?
Lots of wires to the carb, and the dist with the box on it = feedback.
Carb with 2-3 wires, and dist with vac advance = non-feedback.
Either system can be converted, but if you have feedback, you will need to convert to the non feedback ignition to get the best results from a carb/intake swap.

Now, for the 5 speed question. Either the F150/Bronco light duty 5 speed (Mazda trans) of the F250/350+ heavy duty 5 speed (ZF trans) will fit, with a few notes. The clutch is hyraulic on both trans, and you should have a hydraulic clutch currently, making it simpler. You will need the trans of your choice from another 4wd, so the transfer case will fit. 2wd trans are different.
Also, you *may* need different driveshafts, as the 5 speed may be longer than the 4speed, so the TC will sit further back.
The Mazda trans will bolt up to the 300, since it was used behind the 6 and small block V8's only. The ZF, on the other hand, was available with several bellhousing patterns, so you must find one from a small block 4wd to fit your 300.

As for carb choices, most use a 390-500 CFM Holley 4bbl, or 500 CFM edelbrock, and give rave reviews about the improvement.

 

Thank you very much for the info, it was very helpful, it does have a non feedback system. I have been looking online for a couple of days now and have found a places that carry parts for my truck but there is little or no selection to choose from. Any further suggestions on where to began my search for my intake and carb? know of any reputable sites that carry a good selection of parts for my truck?

thanks again for the input again its much appreciated

-James-

 

Summit carry's intakes and carbs, usually has them in stock. Prices are reasonable. Ebay can be a goldmine for used intakes, but used carbs are always a crapshoot.
It's good that you have a non feedback system, as the ignition system is already about the best stock system ever devised.
Offy makes 2 styles of of intakes, a single plane, and a dual plane. The offy DP is very highly reviewed by people that have them. Clifford is another manufacturer, but they're quite proud of their parts.

 

thanks again I checked out the above mentions intakes and will have to read a little further before I make a decision, now I do have another question and am hoping someone can fill me in on how it works. I have what the previous owner of the the truck refers to as a "clutch bypass" it allows me to start my truck in gear. Now I really don't like the idea behind it and I cant start my truck unless the bypass in engaged regardless if I have the clutch is pushed in or not. Any idea why someone would do this? Is there any advantages to have the bypass?

Again much thanks for the info I can use all the help I can get

-James-

 

So there is a button or something you have to push/pull/flip to start your truck???

Sounds like a cheapskates way of fixing the NSS ...

Personally, I would put it back factory.

Now, I could understand a bypass toggle so in one position it worked normal and in the other it was bypassed and there was a push button at the rear of the truck that powered the starter solenoid, I could see the use for that!

-Enjoy
fh : )_~

 

It is really hard to explain without a picture (will post first thing tomorrow) it hangs below my dash to the left of the steering wheel. It feels like a wire with a plastic piece in the middle covered in lairs of duct tape, I have to what feels like make contact with the wire and the plastic piece to get my truck to start.

Thanks for the input

-James-

 

If I understand correctly, you squeeze the layers of duct tape to start it ... Wow!

I just love peeps that do crap like that, Self Proclaimed Auto Electricians ... HACKS!

-Enjoy
fh : )_~

 

YES! That is exactly it! and believe me I would love nothing more to just tear it apart and rewire it right now, but its got to wait till Friday, it is reliable as is and I cant risk it not starting as I leave for work right now, but Friday it has my full attention any idea what I might be getting into?

-James-

 

Before doing anything, ensure the NSS works, I suspect it doesn't, thats why it's bypassed.

Follow your clutch pedal up under the dash, you cannot miss the NSS, it's a pretty big.

-Enjoy
fh : )_~

 

Just went and looked and there is a plastic lever that looks like it at one time connected to a bracket on the back of my clutch pedal. The end of the lever runs into a gray wiring harness and is covered in layers of duct tape. Out of the gray wiring harness is another harness that only has two red wires with black stripes. Those two run into a bundle that break up into my fuse box.

I am wondering if it was bypassed due to the plastic lever or due to the gray box it runs into?
And how would I check to see if the NSS is still working?

 

Sounds the the clutch safety switch failed. Being plastic, it's pretty common.
Either a new one would need to acquuired and installed, or simply find the 2 wires that originally went to the switch, and connect them together.
One way is more original, and won't allow the truck to start without pressing the clutch. The other way is how many of these trucks were rigged after that plastic part broke, but you have to use care to insure that either the clutch is pressed, or the trans is out of gear before starting.
Before the late 70's/early 80's, there wasn't any kind of "Safety switch", and everyone knew to push the clutch or put the trans in nuetral, but the feds decided that common sense wasn't good enough......

 

ok see now it make sense I could see the plastic piece failing often, I am going to rewire to bypass the lever. I am the only one driving my truck and I already start in neutral now so come Friday I'll get under the tape and do the job right this time. Thanks for all the help I'll let yall know how it goes.

 

Yeah, the plastic ends usually break off the switch. The switch itself doesn't go bad nearly as often.
FWIW, I have 3 cars with sticks, 2x83 and an 84. None have one of these safety switches. My Nissan truck and my son's 95 mazda badged ranger, both have them. If either ever fail, I'll just bypass them. At least my Nissan has a button type switch that the pedal pushes, much less prone to breaking.

 

So do you think it would be better to just bypass the lever or should I just bypass the whole unit?