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Old 05/17/18, 08:05 PM   #1
MidwestTexan
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351W Swap

I know this has been asked a hundred times. I found some good threads but couldnít find some answers to questions I have.

I have a 1970 with a fairly stock 302. It has an Edelbrock 1405 carb, performance intake and some long tube headers (not sure what brand as they were installed when I bought it).

Questions:
Will any of the above work on a 351?

What other things will I need to consider when making the swap? The 351 is in great condition so just needing advice on the things Iíll need/mod when putting the 351 in since itís physically a bigger motor. Iím a total newb when it comes to this so any advice, constructive criticism, etc. Is appreciated.
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Old 05/17/18, 08:14 PM   #2
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The carb will probably work, unless it is barely big enough for the 302, 50 more cubic inches needs more air and fuel.

The intake will not work, the 351 is a taller block so the heads are farther apart.

The long tube headers may work, depending on the extra width and height of the block and heads.

... I've got skills, ingenuity and no regard for maintaining any kind of historical preservation or authenticity...My Dad called that sick and wrong
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Old 05/17/18, 08:50 PM   #3
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My Dufflong tube headers worked but I had to put a 1 inch body lift cause they were so close to the passenger side floorboard that my wife wouldn't ride in it because of heat.

"The test of the morality of a society is what it does for its children" Dietrich Bonhoeffer
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Old 05/17/18, 09:33 PM   #4
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You will need a rear sump oil pan. Or enough sup. Lift to clear front differential.

76 SPORT 351W C4 PDB
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Old 05/17/18, 09:41 PM   #5
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Quote:
Originally Posted by half cab View Post
You will need a rear sump oil pan. Or enough sup. Lift to clear front differential.
The Ford (Racing? Performance?) M6675A58 is the oil pan to use.
It is the Crown Vic 351W cop car oil pan that has been sold for 351W swaps into Fox body Mustangs for many years, but you also need the pickup and stud and the dip stick.
Summit Racing sells it for the lowest price, and it costs enough that you get free shipping.

... I've got skills, ingenuity and no regard for maintaining any kind of historical preservation or authenticity...My Dad called that sick and wrong
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Old 05/17/18, 10:11 PM   #6
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Quote:
Originally Posted by MidwestTexan View Post
I know this has been asked a hundred times. I found some good threads but couldn’t find some answers to questions I have.

I have a 1970 with a fairly stock 302. It has an Edelbrock 1405 carb, performance intake and some long tube headers (not sure what brand as they were installed when I bought it).

Questions:
Will any of the above work on a 351?

What other things will I need to consider when making the swap? The 351 is in great condition so just needing advice on the things I’ll need/mod when putting the 351 in since it’s physically a bigger motor. I’m a total newb when it comes to this so any advice, constructive criticism, etc. Is appreciated.

Your carb looks to be 600 CFM. That will work just fine on a 351W. Even a mildly built 351W turning 6000 rpm barely pulls over 500 CFM. (84% VE)

I had Duff long tube headers with a body lift, they fit fine, but I preferred shorties.

You will need a new intake. The 351W has a wider valley due to the taller deck height.

Valve cover clearance may be tight depending on your configuration. Previous owner of my rig added a hood scoop and body lift in order to clear the air cleaner on the 351W, but mine sits up a bit higher and has a taller intake. Just be aware of hood clearances.

Megasquirt EFI 351W, ZF5, AtlasII, full widths, ARBs, frequency-tuned linked suspension, 37" KO2s, full cage, bumpers, etc.
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Old 05/17/18, 10:11 PM   #7
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You will also need a 351W distributor as the 302 dizzy won't work.

'74 U151 Bronco Explorer, WH 2.5"SL, C4, 33's, 4.11's, Aussie locker up front, factory LS in back, 351W Edelbrock intake, Summit 600 CFM carb, stock hood no BL no problem, Flowmaster 50's.
'99 F250 V10 ridin' on 35's. '97 Explorer 5.0
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Old 05/17/18, 11:16 PM   #8
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Thanks guys, I sure appreciate it! As far as installing the motor, is it a direct drop in? Any need to fab mounts, frame work, etc to make it fit? I’m planning on a 2” body lift as I plan to mate it to a zf5.
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Old 05/17/18, 11:19 PM   #9
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Engine mounts and bell housing bolt pattern are identical between the two.

Paul

'71 Wagon, 3.5" WH, F150 disc brakes and steering, 4.11 33x11.50 Thornbirds, Kayline soft top, Hanson bumpers. "Built, not bought"

'68 LUBR, 2.5 + 1 WH, 31x10.50, 4.56, Explorer and 4R70w by EFI Guy, WH disc brakes, Hanson front bumper, Warn winch. "Bought, not built"

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Old 05/17/18, 11:35 PM   #10
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Some other similarities/differences:

-Same overall length. Just the different height already mentioned.
-Same engine family, so many of the same characteristics.
-Cylinder heads almost cross over. The 351 uses larger bolts, but otherwise the dimensions are so close that they will bolt to one or the other block. That's why the headers will likely work.
-One exception to the headers is the type that wrap around the passenger engine mount. Those will usually not rise up enough to fit the taller engine.
-The main bearings are larger, to strengthen things for the longer stroke engine's higher torque.
-Firing order is 13726548 vs your stock 302's 15426378. This was is accommodated with a camshaft where the four cylinders are swapped around. Modern 302/5.0 engines now use the same pattern. So whichever cam is in the engine is the firing order you go by.
-The engine block is wider at the pan rail, due to the larger bearings and longer stroke. Hence the need for a 351w-specific oil pan.
-The main bearing bolt w/stud that they mentioned is needed for any rear-sump pan because the oil pump in in the front (under the distributor as they share the same drive) so the 4wd rear-sump pan requires the rear oriented oil pickup tube, with long neck and support brace bolted to the main bolt stud.
-Bronco engine uses the same item, but with the new pan it's best to get the rear pickup for the pan specifically. Unless someone can tell us if they're the same part number as the one on your Bronco's 302 that is.
-The crankshaft uses the 28oz imbalance factor, so all the same flywheels and harmonic dampers would work in a pinch. But best to source a 351 specific damper (if it doesn't have one already.
-The aluminum front timing cover will fit either engine. So if the 351 was out of a car with a driver's side water pump inlet, you could swap your Bronco front cover and pump and accessory belt drive stuff to the 351 for a clean installation. Unless you're going with a modern serpentine setup.
-Fuel pumps are the same, but if you have a newer engine block (EFI style) you may need an electric pump since it does not have the drive for it.
-If it's a newer block you may not have the threaded hole for the clutch mechanism. The vendors sell adapters for that though.
-Engine mounts are the same for both engines.
-A Windsor will fit without a body lift, but only just. So the body lift will help ease the transition.

Is this an unmolested 351? The Windsors tend to have a higher instance of running hot if they're over-bored too far. So try to avoid one that's already .040" or especially .060" bored out. It's a well known phenomenon, but less so on the later roller motors it seems. But perhaps that's because fewer of them have been bored out? Hard to say.

Probably some other small details, but externally I think we've covered most of them.

Good luck.

Paul

'71 Wagon, 3.5" WH, F150 disc brakes and steering, 4.11 33x11.50 Thornbirds, Kayline soft top, Hanson bumpers. "Built, not bought"

'68 LUBR, 2.5 + 1 WH, 31x10.50, 4.56, Explorer and 4R70w by EFI Guy, WH disc brakes, Hanson front bumper, Warn winch. "Bought, not built"

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Old 05/18/18, 06:21 AM   #11
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great list of stuff from everyone above. One thing I am running into now (put my 351 in last weekend), the drivers side head is basically touching the firewall. I had to cut the extra threads off one of the bolts for the gas pedal, and its still close.

I can shim the transfer case up, but not too far as the Serp Setup lower pulley gets close to the frame crossmember. And don't want to change driveshaft angle too much from transfer case to rear end.

Going to spend a few more hours loosening and tightening bolts tomorrow to see how I can adjust the fit.


Good luck with the swap
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Old 05/18/18, 07:50 AM   #12
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Quote:
Originally Posted by Dlish View Post
I had to cut the extra threads off one of the bolts for the gas pedal, and its still close.
Yup, forgot about that.

'74 U151 Bronco Explorer, WH 2.5"SL, C4, 33's, 4.11's, Aussie locker up front, factory LS in back, 351W Edelbrock intake, Summit 600 CFM carb, stock hood no BL no problem, Flowmaster 50's.
'99 F250 V10 ridin' on 35's. '97 Explorer 5.0
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Old 05/18/18, 10:57 AM   #13
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Me too. But I don't think we've heard of an interference there for awhile now. Either everyone's install was before their time, or they got lucky and their's was shifted enough not to matter, or they just never mentioned it.

Friend installed his late model 351 into a '69 and the only issue he had in that regard was forgetting he had an unplugged port on the back of the head! Yeah, good luck getting that little threaded plug into that one!
I forget if he was one of the ones that drilled a hole into the floor for access, or just pulled the engine out to deal with it.

Paul

'71 Wagon, 3.5" WH, F150 disc brakes and steering, 4.11 33x11.50 Thornbirds, Kayline soft top, Hanson bumpers. "Built, not bought"

'68 LUBR, 2.5 + 1 WH, 31x10.50, 4.56, Explorer and 4R70w by EFI Guy, WH disc brakes, Hanson front bumper, Warn winch. "Bought, not built"

www.wildhorses4x4.com
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Old 05/18/18, 10:58 AM   #14
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Oh, and your idea of loosening bolts and seeing what you can gain is a good place to start.
And don't forget the body bolts too, just in case there's a 1/4" of movement there too.

Good luck.

Paul

'71 Wagon, 3.5" WH, F150 disc brakes and steering, 4.11 33x11.50 Thornbirds, Kayline soft top, Hanson bumpers. "Built, not bought"

'68 LUBR, 2.5 + 1 WH, 31x10.50, 4.56, Explorer and 4R70w by EFI Guy, WH disc brakes, Hanson front bumper, Warn winch. "Bought, not built"

www.wildhorses4x4.com
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Old 05/18/18, 08:53 PM   #15
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made that swap many years ago and at that time it was either K bar S or Duff that offered a "shorten" gas petal bracket. Too bad someone hasn't manufactured that again. With as many swaps that are out there ...... some of you engineers???
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