Thread: 351w build

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Originally Posted by Dave Severson

I think I would go with a good stroker kit for the 351W. I've had a couple of the 408 ci strokers and they run very strong!!!! Hard to beat what you get in a stroker engine package if you go buying the parts individually. Last one I got was from Competition Products, all good stuff an made in the US even!!!!

Here's a link to a similar kit;

HRC, Pro Series Race Assembly, Ford SB (408), 4.030" Bore-Competition Products

Oh, yeah, had Tricflow heads on it, too

My brother has a 72 mustang and he pulled out the 289 and is in the process of building a 408 for it. So would I have to bore it .040? I think that's it right? What I am wondering is for my build what measurements should I have inside. Meaning like angle of plugs. Intake runners combustion chamber, exhaust valve, valve springs, max lift. My brother told me what sizes he is putting on his but I don't know what is best for me. I don't necesserally need exact measurements just ranges for different possibilities. He is building to put a supercharger and I am not so his build is going to be a lot different then mine.

Well, that kit is a .030 overbore on the 351 block with flat top pistons. The heads had 2.02" intakes 1.60" exhaust and if memory serves me correctly 64CC chambers and 180 runner size.

Originally Posted by Dave Severson

Well, that kit is a .030 overbore on the 351 block with flat top pistons. The heads had 2.02" intakes 1.60" exhaust and if memory serves me correctly 64CC chambers and 180 runner size.

Ok so how do you figure out which size of each of those you want for different purposes of th car. I mean, I know you can go with different sizes for different things I just don't know what the ranges are to figure them out. I don't necessarily want t be told every little thing to buy and what size id like to try to figure out some of the things myself but I would also like some help on how to determine what size of what is best for me. And by the way. I really appreciate all of the help you are giving me. I know it probably gets annoying newbies askin a lot of dumb questions all of the time

Bore and Stroke are determined by what size engine you want to run. Chamber size is one of the critical numbers in determining the Compression Ratio. Valve size and runner size I just go with what I know worked good for the street. Had it been an all out race engine then I would have used a 2.06" intake and a 200 or 210 runner. Experience and listening to the guys and companies that build racing engine is where a lot of this information comes from.

Thanks man I really appreciate everything. So do you hae a project you are working on right now

Yeah, way too many projects going at once!!!!! (As usual)

That information helps quite a bit Shawn, the one thing that is missing though is the vehicle weight.....as I mentioned I would definitely build a 351W in a Pinto a lot differently than one for a Galaxie (and it happens I have built 351s for both LOL)

To start at the basics the first priority will be building the bottom end (short block) of the engine. Regardless of what you do the bottom end is the critical end as far as the engine staying together.

The first step will be actually picking the block you will be using. Personally I think I would look for an 85-95 block as it’s already set up for roller lifters. If you use an earlier block, roller lifter can be retrofitted or a flat tappet cam used. There is nothing wrong with a flat tappet engine, however with the current oils a roller cam would likely last a bit longer and it does free up some power over the flat tappet cams. The block should be completely cleaned and checked by the machine shop. If necessary the deck surface should be milled flat and the main journals line honed. Over boring the engine is done primarily to ensure a good cylinder and for a street motor should only be done to the minimum oversize necessary. Any displacement or power gains even at .060 oversize will be minimal, and large overbores (over .060) run the risk of overheating or cracking cylinders.

For a primarily street motor that will turn no more than 6000 RPM without power adders (supercharging/ NOS etc) the stock crank and rods will do fine. If necessary the crank should be turned the minimum undersize necessary to clean up the journals. The rods should be resized. Balancing is pretty much an optional operation that can also free up some horsepower, but is not really necessary unless a lot of parts have been mixed and matched (rods from one engine, crank from another, and new pistons).

Pistons choice will be dependent on a few factors. First is piston type; Cast, Hypereutectic, and forged. Cast pistons are basically OE style and lowest cost. The Hypereutectic are a bit more pricy but are a stronger piston, however they are also more brittle, and more prone to damage from detonation. Forged is the most expensive and strongest piston, and suitable for power adders like NOS and super/turbo charging. In most street applications with a relatively stock motor and 6000 RPM limit the cast pistons will do fine. JMO but if I felt the need for a stronger piston, personally I’d skip right over the hypers and go to a forged unit. After choosing the type of piston, the next step will be to choose the part number that will provide the desired compression ratio for the heads being used.....basically you need to make the piston/head selection decision at the same time.

Now the heads, cam and intake which must all work together........ and this is where reading dyno charts comes into play.

In general terms the more compression the more power the engine is capable of making.....the limiting factor for compression will be the quality of fuel available. Generally speaking the static compression ratio for an iron head motor with premium pump gas will be limited 9-9.5:1and 10-10.5:1 for aluminum heads. But static compression is only a part of what has to be looked at.....the other part is the dynamic compression ratio. This gets into a long involved discussion involving cam profiles, bleeding off cylinder pressure, volumetric efficiency etc so rather than type it all out here I would strongly suggest you type “dynamic compression ratio” into a search engine and do some reading. It’s your pistons and cylinder heads that will determine the static compression ratio of your engine.

When looking at heads you will also need to look at valve and port size, and depending on your application bigger is not always better. Larger valves and ports will allow more air/fuel mixture into the cylinders, but if the air fuel mixture is moving too slowly the fuel will fall out of suspension, and makes the engine “lazy” at lower RPM. Basically this is where you need to know what RPM you’re targeting your engine for. An engine designed to be efficient at 5500 RPM is not necessarily a lot of fun in a car driven 99% of the time at 2400 RPM.

So now we are really down to HAVING to look at the car (weight) and how it is going to be driven to really start making part selections. As I mentioned earlier I would definitely look at a different combination for a 4000 pound car than I would for a 3000 pound car. To do that I’ll make some assumptions.....the car will be driven primarily on the street and see occasional highway use at 75 MPH. Max RPM will be 5800 RPM. I want to be able to cruise on the highway between 2200 and no more than 3000 RPM (the cruise RPM will be determined by tire size and gear ratio....it is also where an overdrive transmission really helps).

Now on a 4000 pound car I would be looking to make as much torque as possible at the lower RPM range just to get the heavy toad moving. As a general rule of thumb I can get the torque in the lower RPM range, but I’m going to sacrifice power in the upper RPM range. That being the case I’ll be reading dyno charts for a combination that will produce as much torque as possible right off idle. This usually means 1200 RPM and up.......when you start looking at parts combinations with the torque being produced at this lower RPM, they generally run out of steam by 3500-4000 RPM.

In the case of a 3000 pound car, it will not take as much power to get the mass moving, so I can afford to lose a bit of bottom end torque and move the power band higher in the RPM range, basically instead of running out of steam at 4000 RPM it will pull strong to say 5500 RPM (think on ramps and the drag strip).

Of course you also get more flexibility with an overdrive transmission...but that’s a discussion for another time.

As you can see you really need to set the parameters that the engine will operate in before you start making parts selections to get the combination where it needs to be. Once you have that information then it’s simply using the dyno charts to see how different components interact with each other to get the combination where it needs to be in the RPM range.

As always, well said MikeP!

Mike - good information

(I do have to ask - are you a secretary by any chance? It would take me a week to type that )

".....are you a secretary by any chance? It would take me a week to type that....."



No but I did a lot of report writing/typing back in my military days.

Not as fast as I used to be though, or this reply would have been done yesterday.

.

Thanks a lot mike. I appreciate how you broke it down for me. I know car wise its inbetween 5 cars I'm just not sure what car I want. I'm thinkin probably a 65 to 69 mustang. I have other choices but that one is on the top of my list. I've always loved stangs. Those are pretty light compared to some of he other body styles of cars I'm looking at. If I take a 351 block to a 408 will that fit without cutting nd welding? I know some of those came with a straight 6 so I'm just hoping I can find one with a 289. I'm thinkin my engine should fit in the v8 body style but I'm not sure of the 6. Oh well I will keep looking. And once again. Thank you

Building the engine to a 408 stroker will not physically alter the the external dimensions of the engine. The 6 Cylinder engine compartments are the same physical size as the V8, just a motor mount change, but you will want ot look at suspension, brake and cooling system upgrades along with a possible rear end upgrade.

The 351 based engine should slip right in, but you will definately want to install a set of full legnth headers to get the maximum benefit from what ever engine combination you end up using.

Originally Posted by adrenaline

I know car wise its inbetween 5 cars I'm just not sure what car I want. I'm thinkin probably a 65 to 69 mustang. . I've always loved stangs. Those are pretty light compared to some of the other body styles of cars I'm looking at. I know some of those came with a straight 6 so I'm just hoping I can find one with a 289. I'm thinkin my engine should fit in the v8 body style but I'm not sure of the 6. Oh well I will keep looking.

If you find a pre 67 Mustang with a 6 cylinder, it'll have a lighter suspension and will need to be updated to a 8 cylinder setup. Not a big deal, it all bolts in. The 289 was last used in 67 also. In 68 Ford began the use of the 302, If you do find a 289 in a 68 it'll be somewhat of a rarity. They are out there but rare. In 67 Ford went to a larger Mustang to be able to use the 390 FE, so that makes getting a 351 in easier.
Hope it helps some.

Ok so I've been pricing out a lot of things for the 408 build and either I am looking at too big of a price or the 408 just isn't for me yet. I don't have a particular budget but te 408 parts I was looking at loked like around 7k for the whole motor. So what I am wondering does anyone hae some ideas for a cheaper set up without sacrificing quality or is that petty much what a 408 is going to cost me in parts? If so does any one hve some other route ideas for me? Still want to do a v8. I would rather do the 408 if I can fnd a cheaper setup

Watch sites like Racing Junk, Craigslist, Epay... sometimes you can find someone bailing out of a project and get a deal...

OH, there's an old saying, Speed costs money. How fast can you go?