Engine swap 302 or 351?

[JB]

I have just about pulled my motor out and am not really sure what I should do. I think that rebuilding it myself would be harder and more expensive that simply purchasing a reman long block. What do you think?

If I decided to go up from the EFI 302 to a EFI 351, what all would need to change? Would I need a different computer for the 351? and would all the plugs and wiring harness and crap work with the 351? motor mounts are the same right?

If you were going to purchase a reman 302, does it come with a cam and crank? If not, what would be good ones to buy?

What is the difference in speed density and mass air?

What it the difference in the fuel injection between Broncos and the older 5.0 Stangs?

I am really trying to learn here as I have never done an engine swap before. I just want a semi-reliable, smooth running motor. Its does not need gob and gobs of HP, but a little extra would be nice. I guess what I am asking is , what would you do if you had a choice between the 302 and 351, keeping in mind money is a factor.(I can use the 302 as a core and save)

[Chadnutz]

If I were you I would rebuild the motor. It will take you more time, but you will learn a lot about engines themselves. You will also save money. It would be good to have a friend that has done it before to guide you. Reman motors are built quickly and cheaply. When you rebuild it yourself you can be sure that it was done correctly. The tools are all cheap except the torque wrenches.

Nutz

[Krawler68]

Go with a ford motorsports GT-40 motor... pretty sweet setup really...you can convert to mustange SEFI fuel injection at the same time... **** rebuilding it... Nutz still wonders if he did everything right and it's almost 2 years after he rebuilt it the first time...

[robertf03]

during my ongoing fuel injection search I've found that the mustang 302 has a different firing order than other 302's.

if you mix and match the components you'll have to do a cam swap. or maybe try to move the wiring harness around to change which injector fires when , but thats canadian.

[fbronco86]

Hey i have done the mustang fuel injection swap in my bronco. I have an 86 bronco with a mass air SEFI. It runs really well. If you wanna put in a 351 your really dont have to change alot new intake and a few other things. I would like to change mine over to a SEFI 351 someday but the 302 is easier to do. You can find all the parts in a junkyard.

[Chadnutz]

Doug thinks I am wondering if I did everything right.

My one regret is that I didn't have the block and head checked
for cracks before I put it all back together. As far as assembly, it is perfect (except for a small oil leak, oops)

Nutz

[Krawler68]

Originally posted by Chadnutz
My one regfet is that I didn't have the blocked and head checked
for cracks before I put it all back together. As far as assemply, it is perfect (except for a small oil leak, oops)

Nutz

Quo Erat Demonstrandum

[Chadnutz]

If I had it to do over again I would do it again. If I found any cracks I would buy a crate motor from Mazda.

How well does the Bronco run Doug? Did you have anything to do with it?

[Krawler68]

It runs OK...but I don't really brag about the work I did to get it going, and yes I did do most of the work... If it blows up I'll most definetley be replacing it with a crate motor or a long block...

[StevenAg03]

i would not go witht he 351. they do not put out much more torque and HP then the 302. also, if im not mistaken, you would have to get all new upper and lower plennums, new computer, and possibly a new wiring harness.

depending on what kind of remaned motor you want, dictates its state of completion. when i replaced my motor i went with a Premium Longblock. it comes with everything from oil pan to heads. i had to use the exhaust and intake off my old motor on them. i personally would not listen to what chadnutz says when he tells you to build it yourself. unless you want to run a modified motor then i dont see how its worth it to buy a shortblock.

i think that i paid somewhere in the neighborhood of $700 for my motor after the core was returned. i have not had any problems with it that were not caused by me. i did burn up two valves but thats cause when we put the headers on and took off the smog crap, i forgot to plug one of the wholes on the back of the heads.

[Krawler68]

If you use mustang plenums and computer you will be cool, as they use the 351W firing order... if you want SEFI on a truck 302 you'll need to change the cam out...

I say FOMOCO racing longblock.

[JB]

The more I think about it, the more I realize that I do not really know what I am doing. The only real problems with the motor is a bad crankshaft bearing, rear main seal, and it was running kinda sluggish every since a half-drunken mud outing so I think I might have got some dirt up in the motor. It is at the point know where I can easily get it out. What I think I will clean it up once it is out. What would you guys do if you had a motor out? New heads? upper, lower intakes? Are all intakes the same, or are the aftermarket ones better?

Sorry, I really know jack **** about motors, trying to learn more.

And what does the S in SEFI mean? And what is GT40?

I want to get it down kinda fast as I am itching to wheel again.

[Krawler68]

Synchronized Electronic Fuel Injection

GT40 is a kind of souped up head designation for Ford mustang Iron Heads...their not aluminum, but they're better than stock.

I say you jusst use that motor as a core on a ho'reilly's motor...it will be easier and prolly' cheaper in the long run.

EDIT: From the sound of it you just need to stay on the street. Wheeling kills your trucks pretty fast.

[mark]

Originally posted by Krawler68
Synchronized Electronic Fuel Injection

Ya sure its not sequential?

-Mark

[Fredo]

Synchronized .....
BWHAHAHAHAHA

Funniest thing I've heard all day.