I have a 1986 F-150 4x4 with a 302 efi. I'm considering building an engine but cant descide what to put into it. I know that the 302 is not a real torque monster but my questoin is will the troque improve very significantly if i turn it into a 347 stroker, or would i be better off building up a 351w? I know that i would end up with more torque with a 351w and that it will bolt up inplace of my 302 but would i need to replace my headers?

 

Decisions, desicisions. First off, yes, torque will go up quite a bit since you're lengthening the stroke. One word of warning about the 347- the piston pin is raised on the piston, placing the pin in the oil groove, which can lead to blow-by problems. I'm doing a stroker also, but only going to 331, which keeps the pin lower on the piston, and uses a shorter rod than the 347. Like they say, there's no replacement for displacement. A built 351 would be nice, but if you're on a budget, look at it this way- if you stick with building the 302, you've already got most of the motor to work with. If you go 351, you're starting from scratch. I'm not sure about the headers being the same, but long tubes are the way to go for torque.

 

ok thanks for the info. Can you give me more info on a 331 stroker? I have heard of 331 but just dont know alot about that setup and what kind of power it can produce.

 

Headers arn't interchangeable between a 302 and 351.

Personally, I wouldn't go for a 347. The 351 would be a great swap, a 351 stroker even better.

The 351 strokers are better than the 347 for the reason petes brought up. The piston pin is so high in the piston that it creates instability problems between the piston and the bore. They've got a bad reputation because it took awhile for the 347 kits to become good, solid, and reliable. They make good kits now but it's still not a superb build.

A 393ci motor uses stock type 351 rods, stock type 302 pistons, and a 3.85 stroker crank that can be had for 200-300 bucks. They're cheap to put a bottom end together but you'll need a good head, cam, intake combo to finish it off.

Since you'd run a carbed motor, a 393 could be pretty cheap. It wouldn't be too hard to put together a 450hp 500tq 393 w/ about 6000 bucks.

 

thanks that helps alot. Because right now I'm in the process of trying to budget out how much this build up will cost me. My budget is slightly limited right now since I'm still in school. But I'm still curious about a 331. I have never heard much about before.

 

IMO the 331 would be more of a reliable motor than the 347 if you are going the 302 route. The 347's are great on the drag strip in mustangs but not for a daily driver. The 302 blocks are not as strong as the 351 blocks as stated above. As much as you are going to spend on a stroker crank and rods and the posibility of additional machine work for clearance to take a 302 to a 331 or a 347 you can build a 351.

 

The 331 is a good stroker, but most likely you could build a 393 for less.

All depends on your budget and what you want the from the engine.

The engine itself isn't a lot different, the bore is the same its just a longer stroke. The longer stroke will provide more torque and a more flat torque curve so it'll have more tq throughout the RPM range.

I went with the 393 because a 331 just isn't enough for my heavy truck. My truck is heavier but a 393 puts out about 420-480 ft-lbs of torque. You'll need a drivetrain that is up to the task.

 

Thanks alot. I will do some more research and let yall know what i chose.

 

There are some good books out there too, check out your local book store.

Barnes and Noble has some HPBooks that are good...

Let us know what else you're thinkin'....

 

I used probe piston's on my 347 stroker & have 15000 miles on it and it has no oil blow by if you use cheep parts on your build you will have problem's !! Yes I ganed major tourqe. It can easyly out pull a 351w !!! That is stock.

Don

 

How well is the computer going to work with the 302 if he strokes it to a 331 or 347. The 1986 is speed density. How would the ECC react to the modified engine?

yomow- What cam did you use in your 347? What year truck is the engine in?

 

the stock ecu wont take it at all. thats why either going mass air or going with a tweecer to tune the ecu.

 

Comp.camshaft, roller it has ford mass air , right now its cyl heads are stock trying to find what heads & intake to useto finish build !!! PART # 35-000-8 FW FORD 351W/302HO HR/SR
CORE C35-8J FW FORD 302 H.O STEEL *** REORDER C35-8I
Special Grind
GRIND # FW 3342B/3343B HR112+3
DURATION @ .050 INTAKE 212 ROCKER
ARM RATIO
VALVE ADJ INTAKE .000 DURATION @ .050 EXHAUST 218
INTAKE 1.60
VALVE ADJ EXHAUST .000 LOBE LIFT INTAKE .3010
EXHAUST 1.60
VALVE LIFT INTAKE .480 LOBE LIFT EXHAUST .3010
VALVE LIFT EXHAUST .480 LOBE SEPARATION 112.0
DURATION .006 INTAKE C/L 109.0
TAPPET LIFT INTAKE 264 CAM ADVANCE 3
TAPPET LIFT EXHAUST 270 HYDRAULIC Y
VALVE TIMING .050 OVERHEAD CAM N
VALVE OPEN INTAKE 3- RECOMMEND VALE SPRINGS
VALVE OPEN EXHAUST 44 DEPARTMENT P
VALVE CLOSED INTAKE 35
VALVE CLOSED EXHAUST 6- SPC INSTR FOR CUSTOMER
LARGE BASE CIRCLE
1.300-1.350
INTAKE LOBE ID 3342B GRIND INSTR FOR CAM SHOP
EXHAUST LOBE ID 3343B FW 3342B/3343B HR112+3
DATE SETUP 02/11/2003 LARGE BASE CIRCLE

Don

 

whatever I would build, it would most likely be carburated.

 

I would definitely go carb in your situation.

Going EFI would be another 2 grand or more.

There is also a better selection of intake manifolds w/ a carb.