Suggestions for 351 Build

1strodeo · Mar 20, 2019

I've built a few engines in my day, the biggest a 302, but they were always complete engines to begin with; not this one.

I have a machined 1990 351W block .030 over, polished 2M crank, E7 heads with valve job, assembled rods/pistons that were balanced with 28 oz harmonic balancer and flexplate.

My main concerns are cam selection - including lifters, push rods and rockers - and flywheel. I have a cam I was told was stock for the engine, but thinking I should get a new/upgraded cam.

I have the larger bell housing that will accommodate either 157 or 164 tooth flywheel. Does it matter which one I go with? Other than being 28 oz does it only need to be compatible with the starter?

As for the cam I've always loved the rumble of a big cam but this will not be a racing engine obviously, and I have no desire to go fast in an EB. But I'd love to have some good torque, have a little rumble and 300HP would be plenty.

Push rods and rockers are a big concern as well, will i be ok just ordering stock rods and rockers for a 90 351W, or should i take some measurements?

Oh and I'll be running a carb for now.

Thanks for any insight and suggestions.

Broncobowsher · Mar 20, 2019

Since that is a flat tappet block, summit house brand cam kit. .448/.472 lift one.
Considered a typical RV cam. Just a hint of a cam at idle that clears up the moment you give it any throttle. Nice flat broad torque curve that will pull until the heads choke up. 300 HP at the crank is very doable.

Bellhousing dictates flywheel size Stock Bronco bellhousing you can only use the 164 tooth. No starter made will work with the 157 tooth flywheel in a Bronco bellhousing.

1strodeo · Mar 20, 2019

Thanks this is a 65 stamped bell housing I’m guessing more than likely not from a Bronco if it matters. Here are some pics

68ford · Mar 20, 2019

110 lobe separation. Lift and duration something close to an edlebrock performer. The tighter than average lobe sep will give you more overlap/lope at idle but always will make more midrage torque due to scavenging. Also puts the torque peak at a lower rpm even though at an idle, it sounds like a bigger cam. Best of both worlds.

SteveL · Mar 20, 2019

If you opt for nonstock rockers or that require the tall valve covers it can give you clearance issues with vacuum or hydroboost brake setups. Its do-able but tight.

1strodeo · Mar 21, 2019

Thanks guys, really appreciate it.

So the 351W push rods are all a standard length?

Broncobowsher · Mar 21, 2019

Push rod lengths are all over the place. The big difference is when a roller cam is used. But even with flat tappet cam there were changes over the years. There were a couple changes is rocker arm engineering. And how ford adjusted valve lash was to use longer or shorter pushrods. So not any 351 pushrod will always be right. But it sounds like all the engine parts are from the same engine. Pushrods for a '90 should fit just fine. All 16 should be the same length. But depending on how parts are machined (decking the block, skimming the heads, grinding the valves) you may need non-stock length.

Timmy390 · Mar 21, 2019

Pushrods.....I went through this with my build. I think there are 3 sizes for non adjustable rockers and another size for adjustable. Early, mid, roller then the adjustable stuff.

Measure the ones you have. All of them. I found a coupe of mine I removed from the running engine were shorter than the rest and bought a new set. Wasn't a huge difference but enough that I was uncomfortable.

As stated lots of factors go into the length you need. I ordered a length checker from AlexParts.com and verified stock would work with my setup.

I had minimum decking done to my block and heads. I also had new springs installed on my heads and shimmed to the correct height.

Tim

1strodeo · Mar 21, 2019

Thanks again, one thing I've discovered with a little research is that the 2M crank is for a 302?? ?:?

I'll measure the rods tonight, plan to assemble this weekend, just want to make sure I shouldn't have a 3M crank

Timmy390 · Mar 21, 2019

1strodeo said:
Thanks again, one thing I've discovered with a little research is that the 2M crank is for a 302?? ?:?

I'll measure the rods tonight, plan to assemble this weekend, just want to make sure I shouldn't have a 3M crank

I missed that......as far as I know early 351w cranks are 3M or 3C and later cranks are 3M A

That 2M should be a 302....

Tim

1strodeo · Mar 21, 2019

Timmy390 said:
I missed that......as far as I know early 351w cranks are 3M or 3C and later cranks are 3M A

That 2M should be a 302....

Tim

Well shit....

1strodeo · Mar 21, 2019

Guy said its the original crank out of the engine he pulled from a 92 F150

Timmy390 · Mar 21, 2019

You need a 7M or 7M A which is the 1 piece rear main seal design

The 351 Windsor’s nodular iron crankshaft has a 3.500-inch stroke and 3.000-inch main journals with a “3M” in the forwardmost counter-weight/journal. A forged steel crank-shaft was never available from the factory for the 351W. The 351W’s “3M” cranks are extremely durable and can take a lot of punishment given ample oil supply and commonsense engine tuning. When the 351W engine was upgraded to a onepiece rear main seal in 1985, its revised nodular iron crankshaft received a revised “7M” identification code. Later in production, it was identified as “7MA.”

Tim

1strodeo · Mar 21, 2019

Thanks again Tim

Timmy390 · Mar 21, 2019

What are the casting numbers on that block?

Might what to verify 1 or 2 piece rear main before getting a crank.

Check any local machine shops as they might have a crank....

Tim

1strodeo · Mar 21, 2019

F0..........

73azbronco · Mar 21, 2019

If your head/valvetrain/block is not standard, use an adjustable pushrod checker to make sure you buy a set of correct rods. For $14 its good insurance.

1strodeo · Mar 21, 2019

here are some measurements i took the other day, I dunno maybe I'm mistaken or had a beer too many and it says 3M I'll have to look %)

B RON CO · Mar 21, 2019

Hi, you have a 351 crank, with a main journal diameter of @ 3".
The small Ford crank mains are @ 2 1/4".
Good luck, of course

1strodeo · Mar 21, 2019

Thanks Ron, it appears I mistook the 2M4 date stamp on my crank for 2MA %) my bad. So I’ve concluded it is a ‘92 crank made on Dec 4th, because it was pulled from a 92 truck and the connecting rods are stamped F2.

Tim the rods all measure within 1/16” and they have cross hatching and each rod has 2 numbers written on it...this among other things leads me to believe quality machine work has been done ;D.

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