OK - so I am admittedly a complete novice with motors in general and I have what should be a basic question for most people here.

I'm looking at an EFI motor out of a 90 F-250 (yes - I just bought an 86 carbed motor - but more on that in a minute). Is converting this EFI motor to a carb as easy as changing the intake manifold and putting a carb on it - or is there a lot more to it?
A buddy seems to think it's more than just the intake manifold that needs to be changed but he couldn't explain what - so I don't know whether to believe him.


Now back to that 86 I bought... I got the complete truck for a great price and was thinking of leaving it complete and maybe making a little $$ by just re-selling it. That is where this new 90 motor comes in. I might be able to sell the 86 for enough to get that 90 for free!

Is one motor more desirable than another (86 vs. 90)? Whichever one I go with will be getting long tube headers, an Edelbrock intake manifold and Holley 650 cfm carb for now. And then in a year or so it will get new heads and a cam and possibly also a TBI style injector run by a megasquirt injection system in the long run.

Should I dump the 86 truck complete if it will make enough $$ to grab this 90 motor which (supposedly - I can't verify) has less mileage?
The 86 is running, in a truck and seems to run well. The 90 is already pulled and I have to take the guys word of "it was running perfect when pulled - I just rolled the truck and therefore parted it out".

 

what are you putting the motor into again?

if the 86 is already a runner why fix something that isnt broken.

the 90 motor i would use as you wish but keep all the efi stuff because when you do go megasquirt you do not want to run a TBI efi setup, those are crap.

to make the 90 a carb motor you will need the proper distributor, intake, and different water pump unless you stay with the serp system.

 

Thanks for the input. The distributor and belts were things I hadn't thought of. Although I'd probably leave the serpentine belt if I changed to carb.

For a quick recap - whatever motor I end up building will go in a 74 F-100 supercab. The truck will see normal street driving as well as off road abuse. Compression needs to stay low as it will be run off Pemex (mexican gas) from time to time when I go down there for the Baja races.

My hopes are to get 400 HP out of it but I don't have a ton of $$ to spend so I'm trying to do it on minimal upgrades and a stock bottom end.

This is where the TBI comes in. I was wanting to use the edelbrock air gap intake manifold that I have for the carb if/when I changed to EFI. A new intake manifold for the EFI stuff is LOTS of $$ from what I have seen and the stock EFI intake manifolds aren't great from what I have heard.

What are your issues/complaints with the TBI setup?

Changing to EFI will come if (when) the carb setup gets annoying. My thoughts on this are the Baja races go from sea level (actually on the sand) up the mountains and all over. If the carb is gonna have issues with elevation changes I'll be frusterated. I think the elevation change is 4500 ft. or so as I've driven through the snow there. I just have yet to do it in a carbed vehicle - so I'm not sure if it will be a pain or not...


The reason for possibly selling the 86 motor was because I need the space. I bought the bronco for the motor and I don't really have room to keep it. I am trying to sell it less the motor which is not as easy as I thought (even at $500 for the entire truck) so I was thinking that if I could get a buyer for the thing with a motor at a bit more than I payed - then I'd end up getting the 90 motor for cheaper.

 

well the early tbi ford used was strictly in cars and never worked right and most of the chevy guys that have tbi injection hate it also.

400hp out of the 5.8 will require cam, intake and possible head work. both motors are flat tappet setups also. if you want a better runner look for an f4te block with a roller cam, this will handle higher rpms better.

the typhoon family of efi intakes on ebay ive heard work well and are cheap.

by the way a carb will suck with that kind of elevation change. possible but would need a really really good quality carb.

 

I was planning on using the chevy TBI - but mainly it is just the injector body I'm interested in. The megasquirt system would be the "brain" and my uncle uses them on all sorts of his customer cars (typically high end sports cars - like the lamborghini diablos he twin turbo charges) and loves the setup. Some people say megasquirt is a pain to tune - but he seems to have it down and says "those people don't know what the heck they are doing" - haha.
It was my idea to use the TBI vs. the later style injectors - but he seems to think it might work.

For the 400 hp - the plan was/is edelbrock air gap intake manifold, Holley 650 cfm double pumper carb, cam (to be selected), ARF or trick flow, twisted wedge heads and then long tube headers - most likely with a cross pipe and 2.5" or 3" exhaust tubing all the way out.

I have read on here that the F4TE is the desireable block, but the reality of it is - this will be a low to mid range RPM motor. Most of the stuff we do off road keeps us in a low gear to keep it in the heavy torque range. I have no issues with a motor that will have the rev limiter set at 5500 or so.
That being said - would I have used the 96 block if the other bronco I got had a 351w instead of the 302 - by all means. Is the F4TE block a big enough of a concern for me to go spend the $$ hunting one down - probably not.

As for the elevation change - I'm sure it will be a carb killer. I just don't have the $$ (or patience for the wiring) to go EFI right now - so it will come down the road. Luckily at this point - I won't see a ton of elevation change for a while to come.

 

400hp from any SBF requires a complete HCI swap, but the stock bottom end is more than capable of supporting that.. assuming it is within spec.
Aftermarket EFI systems are expen$$ive compared to everything else but even a TBI setup will compensate for altitude so it is better than a carb.. by a little bit. A system based around a mustang MAF computer and stock truck wiring would probably be the cheapest but it will take some research and parts collecting to execute.

 

Thanks for the input.

The reason for my TBI idea was to use the megasquirt. My uncle says he gets them for right about $300 and that includes the computer and wiring harness. I haven't installed one personally but he says it's quite simple.

I would think it's probably more simple than even the Mustang MAF with truck wiring that you are talking about.

Plus I would think the cost might be around the same. That $300 seems CHEAP for most aftermarket injection setups.

 

I have never seen any aftermarket EFI setup that cheap, that must be for a wiring harness alone... no intake, computer, etc.. Either that or they're white van specials or something.

 

From what he told me it's the computer and wiring harness.

They aren't white van specials for sure. Whether or not that is some special mechanics discount or something I do not know. He does use their stuff a lot on customer car builds.


And now to add some more confusion with another direction/question...

I have a 96 EFI 302 sitting here that is out of a bronco I parted.

I seem to remember reading that the 302 computer could support the 351w but only to a mild HP level. Since the motor isn't selling quickly or for what I want I have decided I might canabalize it if it would be worth it.
Is there anything off that motor I should grab and keep for the EFI swap later?
OR
Would the computer from the 96 302 run that 90 351w I am looking at?

 

96 is obd-II and a pain to use and wiring would suck.

your uncles experiences are with cars sounds like. a 4wd bouncing around the desert is a whole different animal you know.

Im sure you have heard us talk that you cant build a car motor and expect it to perform in a heavy truck. well same principle here. the megasquirt will work with any type of efi induction. so by going with the efi intake's available out there for Fords you should have no problems. have you been to Ford Fuel Injection and seen whats available.

i would get an 88-93 mustang 5.0 MAF harness, find an A9L or A9P ecu and be done. then run either the typhoon upper/lower or get a typoon lower and edelbrock upper. going this route isnt expensive but its not cheap either. kinda the wrong sport for cheap if you ask me haha

 

Thanks for the tip on the OBD 2. I forgot about that. After doing a california legal (smog **** land) supercharged 3.8L swap into my 89 ranger I have sworn off dealing with any project that requires a smog check. Wiring on that was a pain as well - so both of the above reasons have made me stick with the 70's type stuff which is much more simple to work on.

Yes, my uncles experiences are pretty much all car related. He builds everything from 500+ cubic inch big blocks in '39 ****** to twin turbocharging the v12 lamborghini motors.
While he does specialize in sports/street cars - he does like to hit the dirt and he understands that stuff as well.
I don't see where the dirt factor has anything to do with the EFI I go with here. As long as the computer is isolated from the nasty vibration/bumps we see - nothing else is different. The high dollar race teams pretty much all run Motec. While it's cool stuff there's no way I could afford it.

As far as Megasquirt - I understand it will work with any efi system. I was thinking the chevy TBI for simplicity because it will bolt on a carb style intake - which I have (main reason) and like. The only reason for going EFI is the elevation change deal, so if I can combat that with a simple, cheap system I will. I'm not going for a 600 hp monster here - just something simple and reliable. 400 hp at the crank would be GREAT.

I have poked around on Ford Fuel Injection site. I haven't spent a ton of time - but I've looked it over a little.

I will look around at pricing the mustang MAF harness, the ecu and then the intakes you mention. I bet they will cost a lot more than the megasquirt and TBI, but it is another setup I can look into. I would think the megasquirt would be easier to wire since it is their harness and computer and they give you instructions, but I've wired the ford computer before - so I guess I could figure it out again if I needed to

I know I may sound cheap and yes - I know this sport is ont one to be in if you have any sort of budget... but you have to remember I have a LOT more to build than the motor. Unlike a lot of street guys that buy some better tires and throw the rest at the motor I have to build a complete truck.
My shocks alone cost +/-$600 each and I have 2 per corner. Building a tranny to live in the dirt is about $3,500. Heck - the materials for just the cage in the cab alone is +/-$4 a FOOT and I need 100+ feet for just the cab. This thing is getting caged bumper to bumper. I don't even want to look at what I have spent on gathering parts ove the years...

Anyways - you get the point. This thing is a high dollar build on a budget. Kind of an oxymoron, but building it myself and finding all parts used and for great deals allow me to do so.

The motor is kind of the last piece of the puzzle. I have been collecting parts for 5+ years and $$ is still tight on this so I need to get the best bang for the buck.

Thank you all - well both of you for you input and patience with my rambling.

 

You will need a distributor with advance weights, springs, and a vacuum advance to control your timing.



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Also, there is now an excellent installation article on the D.U.I. Distributor on the Ford-Trucks.com site at:

https://www.ford-trucks.com/article/idx/0/358/article/DUI_Ignition_Installation_In_A_Ford_351W_V8.html

Ignition Lesson of the Month: Hystereses, the difference between the timing as the rpm and vacuum increases to the timing as rpm and vacuum decrease, needs to be kept to a minimum. A precise advance curve accomplishes this.

 

i don't like the HEI ones i am very happy with my msd e-curve no springs to loose or get shot across the garrage, just need to know how to read a chart and use a screwdriver to get the right advance curve

 

I'm not a huge fan of HEI distributors either...


Oh - and a slight update on my motor situation

I came across a freshly built motor that a guy on another forum I am on has. It has forged pistsons, fresh bearings, a performer intake, holley 750 carb, ported heads with a new valve job, gear drive timing gears, etc.

I was originally gonna just throw that 86 motor in and run it for a while and rebuild later, but after thinking about that (not sure how long it would last) and the cost of rebuilding it when I would for a bit I think I might just grab this other motor.

Can you tell I change my mind a lot

New motor was a EFI motor although the guy couldn't tell me what year so I will look to see if it is an FT4E and maybe I will get lucky.

 

not a fan of the gear driven timing. puts a lot of harmonics/vibrations thru the upper portion of the engine and dont provide really any benefits other then NOISE.