How would you build a strong 351W

Post by **Gunnibronco** » Wed Jun 06, 2012 7:43 pm

Well, instead of throwing random questions into other people's threads I started my own.

My longish term plan is to rebuild my 351w from a 96 F250. I bought it on Craigslist, cheap, it had a cracked exhaust manifold. I've only pulled the valve covers & intake, but I'm assuming its getting rebuilt. I'm fine with that, my 302 is good, so I'm in no hurry.

I need schooled on some of the finer points of choosing engine parts. I want to build a reliable, but VERY strong 351. Don't think I'm ready for a stroker, Airbur, I'll save that for Phase III, got to build a stronger driveline for that.

I have:
351w roller block- assuming rods, crank, etc are good, if not, stroker becomes an option.
E7? heads- haven't pulled to check, but read that they are E7's -ready to replace with high end/alluminum heads
GT40 lower manifold- need upper, fuel rails, etc

Are 19lb injectors going to be too small? Should I just plan on bumping to 24lb? I have read that 19lb is marginal for a 351, but that may just be the "go fast" guys talking.

I think I want this cam & 1.6 roller rockers, but know jack squat about cam specs:

http://www.summitracing.com/parts/CCA-35-308-8/

Tell me what you'd change & why.

I want to run aluminum heads, Edelbrock, GT40 aluminum, TFS, AFR. I think the advantages of the aluminum heads outweigh the cost advantage, once you spend the money to rebuild/upgrade iron heads. Some of you guys may say stay stock/cast iron heads. You can state your case, but I pretty much have decided to go pretty big on this build.

What combo of heads/pistons would you use, and what compression ratio would you want? The stock motor was around 8.8:1. If the pistons and bores are alright would you reuse the old pistons?

What size runner is necessary for a 351w? I know a 351 can only use so much air. Does anyone know the airflow specs on the GT40 351 intake?

I was reading about quench and keeping the piston top nearly flush with the top of the block. I guess at that point, my brain tied itself in knots and I stopped processing info.

How do you start planning a motor? Choose a piston first, then a head, or vice versa. Wait to buy a head until after the block has been fully checked, machined, and pistons are chosen? I'd like to start looking for deals on heads and other parts but don't want to buy a part today, that I don't end up using in a year or so.

Post by **ZOSO** » Wed Jun 06, 2012 8:03 pm

For starters that cam is pretty small duration wise. Great for low range. Big power not so much. A compromise is look for a 220-230 duration at 0.050" compression would work great around 10:1. That would require 91oct. Bigger Maf, throttle body, injectors. Then top it off with a good custom tune. Nice afr heads. I'd think around 200cc would work killer. Get the upper and lower ported and matched to the heads.

Post by **ZOSO** » Wed Jun 06, 2012 8:10 pm

This cam would be pretty hot. Would have a nice lope to it.

http://www.summitracing.com/parts/CCA-35-426-8/

One a little mellower. I think this would be a nice match.

http://www.summitracing.com/parts/CCA-35-425-8/

Post by **ZOSO** » Wed Jun 06, 2012 8:13 pm

The heart of a motor is the cam. But its an overall package. Don't build a hot high compression with a little bump stick. And vice versa.

Viperwolf1 · Post by **Viperwolf1** » Wed Jun 06, 2012 8:24 pm

X2. Everything needs to work together to produce power where you want it. 1st step is to figure out how much power you want and where in the rpm range you want it. Then select parts that support those plans. An engine is a compromise. You can't have massive low-end torque and high rpm horsepower. If you put the torque range in between you can have some of each.

Post by **Gunnibronco** » Wed Jun 06, 2012 8:39 pm

Thanks, I understand that everything needs planned out, and balanced. I know enough, to know I don't know enough. I really didn't know where to start sizing a head.

I'm shooting for a crawler motor, as much low end torque as possible. I hope this truck will become less of a dog hauler/hunting rig and more of a dedicated trail/crawler in the long run.

For example, the AFR 205 comes in 58cc & 72cc how do you choose a piston & head to achieve a 10.0:1 compression ratio?

How much detuning would it take to run lower octane fuel? What kind of compression ratio/cam would run low octane? If I see a comparison of cams it would help. Forget the upgraded heads & cam if I stick with 87 or 89? or just go with smaller cam & heads?

Post by **airbur** » Thu Jun 07, 2012 4:50 am

http://www.gtsparkplugs.com/CompRatioCalc.html

For the price of those off-the-shelf cams, you can have a custom billet cam ground by Woody at Ford Strokers. Talk to him about what you're building and he will recommend a cam.

www.fordstrokers.com

Post by **ZOSO** » Thu Jun 07, 2012 5:26 am

You don't even have to go out of state for a custom grind cam. You can get one here in denver. I think the name is cam research.

Post by **Gunnibronco** » Thu Jun 07, 2012 6:23 am

Yeah, I've been thinking that if I go all out, with heads and ported intake, a custom cam might be the way to go. Not too much more expensive, figuring the overall build cost. And then you have a cam built for your set up, not some generic cam for some generic motor. I was at Woody's site last night, looking at stuff. Looks like tmoss from the Mustang sites is the guy to port a manifold.

Thanks, I have a starting point and a lot to think about. Figure the next steps are to tear the block apart and get it cleaned & checked. Go from there.

Chad

Post by **airbur** » Thu Jun 07, 2012 12:36 pm

ZOSO wrote:You don't even have to go out of state for a custom grind cam. You can get one here in denver. I think the name is cam research.

Correct, I had mine done my CAM Research...but....he doesn't use billet.

Post by **RJLougee** » Mon Jun 11, 2012 2:27 pm

airbur wrote: For the price of those off-the-shelf cams, you can have a custom billet cam ground by Woody at Ford Strokers.

My whole engine was built by Woody, 408, custom cam, built on a '95 roller block, AFR185 heads, Crane roller rockers, etc.... $4200 shipped, no core. Of all the local (COS) machine shops I talked to, I couldn't even get a simple answer to questions about clearancing the block on a 393 stroker, I really didn't trust any of the monkeys to build it for me.

So then you decide to build it yourself, run the numbers, can you actually buy all the parts, pay for machine work and get the right tools for that price? I couldn't.

Next question, why decide you are NOT going to do a stroker this go round, when you could do it pretty cheap. I bet if you ran the numbers, it would cost you less to:

A: Stroke it in addition to the existing build, and add upgrade parts.
VS.
B: Rebuild it/stroke it later AND add upgrade parts.
My $.02, Joe

Post by **Gunnibronco** » Mon Jun 11, 2012 4:03 pm

Good advice.

I agree that doing a stroker now would be cheaper than upgrading now and strokering later. When I was considering it I looked at Woody's prices, and thought they were reasonable, especially considering the extra work to clearance for the stroker. I honestly don't expect to ever do the stroker. And if I do, I'd probably have to upgrade my driveline to handle the power. Since I just swapped my f/w D44 & 9" last year, I don't expect to change them again anytime soon. I think if I build my 351 right, it will all I need in the forseeable future, and I'll have a driveline that won't blow itself up.

I don't think I'll go over 35"s. I'll save 37"s, 408's, upgraded axles, tranny, and t-case for down the road.

Is a billet camshaft really needed for our low rpm application. I read that billet camshafts are stiffer, and stay true at higher rpm. But we really don't use camshafts that way.

Tmoss expected that the GT40 5.8 manifold wouldn't need porting. It flows very well, in stock configuration, much better than the GT40 5.0 manifold. It flows better than the 5.0 manifold because the extra width helps lengthen & straighten the runners. If I go bigger than stock, then he said to consider porting.

Post by **kcfeist** » Sat Jun 16, 2012 7:29 am

Personally I would start any build by talking to Scott (CamResearch/MPG heads). He is one of the most knowledgable engine builders out there, and knows all the details of the total package. However far you decide to go with the build he can do it all (block prep, intake porting, head porting/flowing,...). You stated that you are not in a big hurry, which is good, because he is usually quite busy.

Post by **landshark** » Mon Jun 18, 2012 9:56 am

kcfeist wrote:Personally I would start any build by talking to Scott (CamResearch/MPG heads). He is one of the most knowledgable engine builders out there, and knows all the details of the total package. However far you decide to go with the build he can do it all (block prep, intake porting, head porting/flowing,...). You stated that you are not in a big hurry, which is good, because he is usually quite busy.

i second scott at MPG.. he worked with me on my heads and my engine rebuild that i just got back together and iam excited i followed his advice.. he was very knowledgeable, fast and professional.

Post by **Gunnibronco** » Mon Jun 18, 2012 12:02 pm

Cool, I think I'm going to work with someone who can help organize my build and probably sell me a set of heads & a custom cam to match. Its a long way off, so I appreciate the advice. Woody @ Fordstrokers and some other have been recommended. But if there is someone closer to home who is good, I'll look into working with them.

Post by **Shawns Fords** » Wed Jun 20, 2012 7:49 pm

Woody (havent seen him in ages), Scott @ MPG Cylinder heads, or the guys at AMS automotive machine. I cant think of anyone on the western side that does engine work.

Post by **Gunnibronco** » Wed Jun 20, 2012 8:42 pm

I doubt there is anyone out here building custom engines. We have a decent machine shop here, and I can have the basics done here, but rely on someone else to help me pick the right parts to get what I need. I don't want anything radical, just something set up right, to get the most out of a motor.

Post by **Shawns Fords** » Wed Jun 20, 2012 9:17 pm

To me, the easiest way would be to run an overhauled engine and not put a bunch of updated internals, and spend the money on a supercharger. you can have a good solid and strong engine with a little it of boost without the risk of extreme catastrophic failure. Instant throttle response with the Supercharger/Blower and it can run like its at sea level.

Post by **Booger** » Fri Jun 22, 2012 7:18 pm

Shawns Fords wrote:To me, the easiest way would be to run an overhauled engine and not put a bunch of updated internals, and spend the money on a supercharger. you can have a good solid and strong engine with a little it of boost without the risk of extreme catastrophic failure. Instant throttle response with the Supercharger/Blower and it can run like its at sea level.

As they used to say in the old days "Injection is nice but I'd rather be blown". :laughing2:

Post by **Shawns Fords** » Fri Jun 22, 2012 11:07 pm

Booger wrote:
Shawns Fords wrote:To me, the easiest way would be to run an overhauled engine and not put a bunch of updated internals, and spend the money on a supercharger. you can have a good solid and strong engine with a little it of boost without the risk of extreme catastrophic failure. Instant throttle response with the Supercharger/Blower and it can run like its at sea level.

As they used to say in the old days "Injection is nice but I'd rather be blown".

I had an old T shirt I wore out that said "Injection is neat, nitrous is hard to beat, but when its time to gt going, id rather be BLOWN" lmao

Post by **Gunnibronco** » Sat Jun 23, 2012 7:12 am

You guys are bringing back memories of National Trails Raceway, outside Columbus.

Interesting idea with a supercharger.

Thanks
Chad

Post by **Gunnibronco** » Sun Jan 06, 2013 9:56 pm

I'm going to start moving forward with this very soon. I want to tear everything off the block and have it checked out at my local machine shop to see what I've got to work with. I got a set of AFR 185s, and will contact MPG heads/Camshaft Research about a custom cam this week. The AFRs have a large combustion chamber 72cc(maybe too big) I need to choose pistons and maybe some machine work to get to a mid 9 compression ratio, I think. I'll see what the cam guys think I should do to get there.

I'm wondering how to gear the truck. Right now I've got a NP435 & 33's and am running about 2300 rpm @65 mph. My next set of tires will be 35's, that will put the r's under 2200. I'd think this will be fine with a built 351.

In the long run, I'm set on an OD 5 speed trans, and may have just sourced one. I know this will require a regear of the axles.

With the ZF trans, 4.10s & 35's it would run about 1950 rpm @ 65. Is that too low to expect to run this motor? Just wondering what to expect from a 351. I'll need to tell the cam designer what my expectations are. Maybe he'll have ideas too. 4.56 puts me back about 2150 rpm @ 65. I'd like to keep my rpms as low as possible, without lugging on the motor.

Thoughts?

Thanks
Chad

Post by **aaah1** » Wed Jan 09, 2013 4:19 pm

I run a bored with 351W with 4.1,Zf, and 35s. I have no problem cruising at 65 in Od. I cant really put in 5th though till about 50 to 55 or else Im luggging it a bit. Power is not a problem though even that low for me with a simple RV cam. I have even considered gearing it lower so it revs less at like 75-85. especially since I have the Zf first gear.

Post by **aaah1** » Wed Jan 09, 2013 4:20 pm

+1 on the supercharger. I love a supercharger whine, would love to supercharge mine.

Post by **Gunnibronco** » Wed Jan 09, 2013 5:24 pm

Thanks for the 1st hand info. JD/Jesus_Man has the same kind of thing to say. He mentioned that he does have to downshift to pass.

I don't run much over 65 in my Bronco w/33's now, and I don't really do much highway passing. So those concerns are minimal. But I do need to keep it able to do 65 up & down our roads.

I've spoken to Camshaft Research, and my local machine shop about how I'm going to get close to a 9.5:1 CR. With the large chamber AFR heads it will be a trick. I want to minimize milling the head & block, because it could lead to intake/head/block misalignment problems, and then need sent out of town to fix. My local machine shop can do basic stuff, but does not have the capability to do some of the finer processes.

I've spent a bunch of hours in front of CR calculators & piston catalogs and I'm starting to understand how to end up where I want. I need to tear the motor down, and have it all measured for real next. Then I can move from my "best guesses" to "actual".

Right now I see 2 ways to get to my goals.

#1 KB flat top pistons, w/4.0 cc- this piston is affordable, but is very specific to require a .040 quench. So my block would have to be decked (sent out of town) for this.
Advantages- affordable pistons, small quench height
Disadvantages- cost of decking block, possible head/intake/block alignment issues

#2 find another piston, probably forged, more expensive that is not as "picky" about quench, use an expensive low volume headgasket
Advantages- no block to deck, avoid possible alignment issues
Disadvantages- larger quench, expensive pistons & headgaskets

I'm currently leaning towards option #1, it will probably be the same price as option #2. But, I'm putting the money towards decreasing quench height, a good thing, instead of sinking money into a forged piston I don't need, and ignoring quench.

Post by **75DBE** » Wed Jan 09, 2013 10:46 pm

So if anyone was going to do a supercharger, what are the options out there? Anyone familiar with them enough to put down some basics?

Post by **Gunnibronco** » Wed Jan 09, 2013 10:55 pm

I did a little reading on it, but am no expert. The options I saw were serpentine belt mounted Paxton (I think). Somewhat generic, you'd have to route the intake/supercharger yourself. Also, you would have to build/mount/route an intercooler to get the most from it.

It negates our altitude, and is a cool option.

Its too expensive for me to consider. I wouldn't use the 351 motor I have without rebuilding it. So I'd be doing everything I'm doing now, and adding the supercharger. And I think you'd want to build a different motor with CR, cam specs, etc. So I'd want to do it now, not wait and add it later.

Post by **Justin** » Thu Jan 10, 2013 12:05 am

75DBE wrote:So if anyone was going to do a supercharger, what are the options out there? Anyone familiar with them enough to put down some basics?

You might track down Coby Hughey. I can't remember his username here or on CB, but he was building a supercharged uber-Bronco. I'm guessing he'd have some insight for ya.

Post by **ZOSO** » Fri Jan 11, 2013 7:09 am

you'd want a roots style. KenneBell used to make kits for the 5.0 mustangs that would work perfect in a bronco. A roots gives you instant boost which means instant torque/power. A paxton/vortech/procharger are based on rpm. they wont give you any bottom end and gobs of power in the upper rpms. They are like a turbo.

Post by **Gunnibronco** » Tue Jan 29, 2013 8:46 pm

This motor is going on the back burner. My 302 & EFI are running great and my D20 is probably original. I'm also tired of my old NP435, its not a great shifting transmission. Think rowing a boat. I got a good deal on what appears to be a nice ZF5. Knock on wood bangtard

I'm going to move forward on an Atlas transfer case instead of this motor now. I have a line on a used one, but I think he wants too much, and I'm waiting on prices for new ones.

I'm considering axle gearing right now. I'll probably run with my stock set up for a little while after installing the ZF & Atlas. I just won't use 5th gear. Leaning towards 4.86s.

Thanks for the input.

www.ColoradoClassicBroncos.com