What is the diffrence (talking engines)
Thread Starter
|
Elder User
Joined: Nov 2005
Posts: 575
Likes: 1
What is the diffrence (talking engines)
Is there any diffrence between the heads on an EFI 300 and a carb'd 300. I know the intake manifold is diffrent (obviously), but how diffrent are the heads? Also, are there any diffrences between the two blocks (i.e. tranny bolt patterns, location of engine mounts, etc)? The reason I ask is because there is a guy who has a 300 out of a late 70's truck that he is willing to sell me for $125. He swapped it out for a 351, and doesn't need it anymore. It ran when he pulled it, and its been under a tarp in his barn for a while. Am planning on building up my '94 EFI 300, but if the heads and block are the same, then I will just buy the engine he has, build it up, and drop it in with the EFI intake and exhaust manifold and all that. I'm not really concerned about the computer working, because I'm switching to Megasquirt II, I'm mostly concerned about the head and block diffrences. Also, do ya'll think I could swap the pulleys so that I can still run a serpentine belt?
Senior User
Joined: May 2004
Posts: 347
Likes: 0
the blocks and the internals of the engine are exactly the same. the head is different. just use the head off of your efi engine or get a remaned one. also you will want to use the mechanical fuel pump block off plate off of the efi motor. when they went to fuel tank mounted pump in 87 they just put a block off plate on the block, the cam still has the provisions for a mechanical fuel pump after 1987. you will also not want to forget the efi motors used a serpentine belt, but i think that is obvious.
Posting Guru
Joined: Jun 2002
Posts: 1,288
Likes: 1
From: redding U.S.A.
If you are planning megasquirt, i would use the carb head. From what i hear on these forums the carb heads flow a bit better.
The EFI head also has a different combustion chamber, which calls for different spark curves.
When I pulled off the head to my 1995 300, i was suprised by how small the ports were, both intake and exhaust, to be feeding a 50ci cylinder.
The EFI head also has a different combustion chamber, which calls for different spark curves.
When I pulled off the head to my 1995 300, i was suprised by how small the ports were, both intake and exhaust, to be feeding a 50ci cylinder.
Thread Starter
|
Elder User
Joined: Nov 2005
Posts: 575
Likes: 1
So the combustion chambers are different... ok, now, will the EFI intake manifold bolt up to the carb head? I mean, are the bolt holes any different, ports located slightly different, etc.? What I had originally planned to do was either get a junkyard head in good condition and get it ported, polished and indexed, or get one of the blueprinted heads from Crane, which ever was cheaper. But since I'm getting the block bored .060 over (among other things), when he offered the whole engine for $125, and I can not have too much down time on this project, I started formulating the idea of just building a drop in 300.
Thread Starter
|
Elder User
Joined: Nov 2005
Posts: 575
Likes: 1
Ok, when I finally get around to cleaning up my engine here in a week or so, I'll just measure the distance between some of the bolts and have somebody with a carb'd head do the same. I would do it sooner, but it is still too cold outside to use the hose, and the whole engine compartment is caked with mud.
Post Fiend
Joined: May 2004
Posts: 5,277
Likes: 0
From: St George, SC I-95
Rhetor,
the efi head is missing 2 bolt holes....IIRC. They will need to be drilled and tapped if going from EFI to carbed intake, but if going from carbed to efi I dont think there will be a problem.
the efi head is missing 2 bolt holes....IIRC. They will need to be drilled and tapped if going from EFI to carbed intake, but if going from carbed to efi I dont think there will be a problem.
Trending Topics
Postmaster
Joined: Mar 2002
Posts: 3,545
Likes: 4
From: Coal Region
u dont wanna hear from me because i dont know anything about anything but the EFI head has a "fast burn, swirl" design and something about the timing and not running smooth with swapping a carb head to the EFI block.
heres more reading on the subject...but why are u still going .060 over? u said u werent anymore...but again, what do i know.
heres more reading on the subject...but why are u still going .060 over? u said u werent anymore...but again, what do i know.
FTE Stories
Ford Trucks for Ford Truck Enthusiasts
Top 10 Fords at 2026 Carlisle Ford Nationals
Joe Kucinski
3 Best / 3 Worst Parts of Modern Ford Ownership
Brett Foote
10 Amazing Upgrades That Solve Common Ford Truck Owner Headaches
Pouria Savadkouei
Every 2026 Ford Engine Explained
Brett Foote
10 Ugly Ford Trucks That We Still Kinda Love
Joe Kucinski
10 Things Every Truck Owner NEEDS (2026 Edition)
Michael S. Palmer
Rezvani's Latest Post-Apocalyptic Monster Is a Ford F-150 Raptor Underneath
Verdad Gallardo
Top 10 Most Expensive Ford Trucks Ever Sold on Bring a Trailer
Joe Kucinski
2027 Ford Super Duty Buyer's Guide (Every Model, Engine, & Package)
Brett Foote
Thread Starter
|
Elder User
Joined: Nov 2005
Posts: 575
Likes: 1
optikal, why do you have this preconcieved notion that I hate you? LOL. Dude seriously, this is a forum. Sometimes people get $#!++y with each other, sometimes people talk $#!+, but that doesn't discredit everything you have to say! I said I wasn't going to go .080 over, because it was too much work (and my machinist didn't wanna do it 
). The reason I asked this is because there is a guy who has a 300 out of a late 70's truck that he is willing to sell me for $125. I am planning on building up my '94 EFI 300, but if the heads and block are the same, then I will just buy the engine he has, build it up, and drop it in with the EFI intake and exhaust manifold and all that. If they aren't compatable, then I will just get a junkyard head in good condition and get it ported, polished and indexed, or get one of the blueprinted heads from Crane, which ever was cheaper in the long run.
). The reason I asked this is because there is a guy who has a 300 out of a late 70's truck that he is willing to sell me for $125. I am planning on building up my '94 EFI 300, but if the heads and block are the same, then I will just buy the engine he has, build it up, and drop it in with the EFI intake and exhaust manifold and all that. If they aren't compatable, then I will just get a junkyard head in good condition and get it ported, polished and indexed, or get one of the blueprinted heads from Crane, which ever was cheaper in the long run.
Postmaster
Joined: Mar 2002
Posts: 3,545
Likes: 4
From: Coal Region
ya where did my link go? i posted two links and they went POOF! nice job moderators.
ill dig up several articles i have on where to work the stock head and the reasons why a head swap isnt ideal (efi - carb or carb- efi).
i dont hate ya man, just bustin ur ***** ;-)
ill dig up several articles i have on where to work the stock head and the reasons why a head swap isnt ideal (efi - carb or carb- efi).
i dont hate ya man, just bustin ur ***** ;-)