351W 408 Stroker Kit

69Tool · Jun 13, 2007

Hello,

I am looking at rebuilding my stock 1969 351W. I am trying to go straight stock or put in a 408 stroker kit. I do not know much about a stroker kit, so please bear with me.

I love bottem end torque and take off, but I am not worried about racing this car, I simply am after a fun driver with lots of bottem end power.

If I choose to go with a stroker kit, will I need to replace cam, heads or anything else? Currently I have a mild cam in the car that is brand new, along with stock heads, magnaflow headers and exhaust.

I have a fresh rebuild on my FMX transmission, will it handle the power of the stroker kit if I choose to go that route?

Is a stroker kit overkill for a weekend driver with a desire to go fast off the line?

Thanks for the help...

rbohm · Jun 14, 2007

69Tool said:
Hello,

I am looking at rebuilding my stock 1969 351W. I am trying to go straight stock or put in a 408 stroker kit. I do not know much about a stroker kit, so please bear with me.

oh lord give me strength to deal with NOOBS JK

69Tool said:
I love bottem end torque and take off, but I am not worried about racing this car, I simply am after a fun driver with lots of bottem end power.

stroking an engine is an excellent way to increase low end torque.

69Tool said:
If I choose to go with a stroker kit, will I need to replace cam, heads or anything else? Currently I have a mild cam in the car that is brand new, along with stock heads, magnaflow headers and exhaust.

the simple answer is no. the better answer is, while not necessary, aftermarket heads, and a cam matched to the rpm range the engine is being built for, and that also includes an intake and headers also designed for the engines rpm, will maximize the engines output. however these items can be added when you have the money for such items.

69Tool said:
I have a fresh rebuild on my FMX transmission, will it handle the power of the stroker kit if I choose to go that route?

the stock FMX is one tough customer. in fact the AOD and its decendants are based off the FMX. as long as you are not making more than about 450hp, and you wont be based on what you want, your trans will be just fine.

69Tool said:
Is a stroker kit overkill for a weekend driver with a desire to go fast off the line?

that depend on your attitude. for me "if some is good, more is better, and too much is still not enough"

done right a stroker engine can be a daily driver, which means that for your application it will be perfect.

69Tool · Jun 14, 2007

Thank you for your input. I am actually not a Noob, but I have been on a long LOA, I bought this car about a year ago and have not done much work on it, hence no posting. I used to spend a lot of time on here when I had my previous car, a 67 GT fastback, which I was formerly known as also.

So if I add the stroker kit for now while using a mild cam (mine is brand new), 3.25 limited slip diff, FMX tranny, and the stock heads, I can generate more power as a good daily driver, and then modify components if I choose to later on? Thanks again.

SoCalCruising · Jun 14, 2007

Yes, to your last Qs. Without changing the heads/intake/cam, you will make much more torque, a little more power and do it at a lower RPM. When you add heads/cam/intake the power will greatly increase, and do so into a higher RPM range. Get the short block right, then the rest can be added as $$ becomes available. Of course, this is much more work (tearing down top of the engine later) than doing it all at once, but it spreads out the cost. I would also consider a long-rod (i.e., not the stock-length rod) 393 kit, if I were you.

69Tool · Jun 14, 2007

Sounds great, thanks again for the advice.

ratio411 · Jun 14, 2007

If you are just doing a straight rebuild for the street, the most economical way to go is the 393 crank alone.
Doing it this way only adds a trivial amount to the cost of a 351 rebuild.
The crank can be had inexpensive, you then use all the stock components except substituting 302 pistons rather than going back with 351w pistons.
Then, when you take your heads apart to rebuild them, port the exhaust while they are bare. The engine you have really has excellent heads once they have been opened up a bit! With porting they outflow or match many aftermarket heads.
The 393 crank, .030" over 302 pistons, and a little grinding on the heads will have you crusing strong.

69Tool · Jun 14, 2007

ratio411 said:
If you are just doing a straight rebuild for the street, the most economical way to go is the 393 crank alone.
Doing it this way only adds a trivial amount to the cost of a 351 rebuild.
The crank can be had inexpensive, you then use all the stock components except substituting 302 pistons rather than going back with 351w pistons.
Then, when you take your heads apart to rebuild them, port the exhaust while they are bare. The engine you have really has excellent heads once they have been opened up a bit! With porting they outflow or match many aftermarket heads.
The 393 crank, .030" over 302 pistons, and a little grinding on the heads will have you crusing strong.

Thanks ratio, what compression are the 302 pistons? Also, how hard is it to port the heads? Thanks again.

ratio411 · Jun 14, 2007

69Tool said:
Thanks ratio, what compression are the 302 pistons? Also, how hard is it to port the heads? Thanks again.

The compression ratio is a product of exactly which pistons you use...
Flat top, dome, or dish. You will have to chose a piston style and compression ratio for any piston you use in a rebuild, no matter if you are stroking it or not.

68RCodeConv · Jun 15, 2007

Head porting is easy if you know what you are doing.

If you don't know what you are doing you can: (1) ruin the heads by grinding into the water jacket, or (2) grind off a bunch of metal and not increase the airflow one bit.

If you are inexperienced in this matter then IMO you don't need to be experimenting on your original heads. Either give them to an experienced head porter or just break down and buy a good set of aluminum heads.

When you start getting into the "more power" scenario it starts a chain reaction of better valve springs, new rockers, new pushrods, new valves, etc. and you end up with serious $$$ in your "stock" heads.

Or just keep everything just like it is and build the 408 short block. Change the (likely) 3.00 gears you currently have to 3.50 and you will have all the power you need.

knifefighter · Jun 16, 2007

I don't get it.

I don't get it.

Why on earth would anyone consider doing all that work to your engine and leaving the 351W heads stock?

Those heads are dogs stock. And for what you would pay to get them upgraded you could just simply buy a set of aftermarket heads that would flow so much better.

Personally, with your setup. (And I am assuming you have actually pulled the starter and looked at the date codes on the block to verify the 1969 date.)

I would simply slap on some aftermarket heads if your bottom end is ok. (Ok, slap on is an understatement, you will probably need to get the right length pushrods also.)

If the bottom end needs a rebuild, and if you truly have a sought after 1969/70 block, then it will certainly be great for stroking. They were the best years for bottom end strength.

But I would totally forget about stroking the bottom and leaving the heads stock. Just ridiculous. (No insult intended guys, but he is not talking 289 or 5.0 here!) I mean, some used GT-40P heads would outflow stock 351W heads! (And still underperform for your current setup)

If your engine turns out to be just a plain vanilla 351W from a less desirable year, then I personally would seek out a 94-95'ish roller block for my mods . . . But hey, rebuilding the block you got is often the cheapest route. (I paid $600 for a low milage junkyard one. kinda irritating because it runs too good to mess with, gonna build up the old one instead.)

/s/ Danno

ratio411 · Jun 16, 2007

knifefighter said:
I mean, some used GT-40P heads would outflow stock 351W heads! (And still underperform for your current setup)

The early W heads are not the junk you assume!
With proper porting they outflow many aftermarket heads and on par with some others.
GT40s don't stand a chance once the W head is ported...
Plus you have the issue of making the things work if you get the Ps and their goofy plug position.

If the heads are not ported, then I agree.

Also, he is not looking for a race engine.
Ported Ws would be awesome on a street 393.
Of course if you want to really turn up the rpms, then they won't do.

knifefighter · Jun 17, 2007

Zactly

Zactly,

Gotta rework 'em. I hear you can get a backyard porting for about $150 if you take them apart yourself and put them back together. But I think just porting them will not get you where you want to go since low end torque is the goal.

A lot easier to just replace the heads with nice aluminum after-market heads. And do you still have a cast iron water pump? Amazing what those weigh.

Stock they don't flow enough for your current setup, and they certainly don't flow enough for a stroked engine.

Danno

bnickel · Jun 18, 2007

i've seen flow charts that show the ported stock 69/70 351w castings outflowing box stock E'brock heads so don't say they won't flow enough air, the main advantage of the aftermarket aluminum heads, besides weight, is that most of them have higher port velocity which the keeps the air/fuel mixture atomized better and they allow you to run more compression. actually aluminum heads need more compression than comparable iron heads to make the same power because they shed heat too quickly, but we won't go into that here.

IMO, he either needs to port the stock heads or buy some better flowing aftermarket heads, they don't have to be aluminum either, he could use a set of World Products Windsor Sr. heads or some Roush 200 heads.

69Tool · Jun 18, 2007

The heads I have currently are the stock cast iron heads. I may look for a pair of used aluminum heads, otherwise, I will be porting the cast iron heads. Thanks for the info, it has helped me learn alot.

Cheers.

Max Power · Jun 18, 2007

Porting the factory W heads is a slippery slope. With a fresh short block, you will need at minimum a fresh valve job. If you are doing the valve job, you will want to install hardened seats on the exhaust side. To run a cam that won't crap out at 4000 rpm with 400 cubic inches, you will need to convert to screw-in studs. With screw-in studs, you will want to run pushrod guide plates, and of course, hardened push rods. Of course, in this scenario, you will need a decent quality rocker now that you have converted to adjustable.

Now that you have spent $750-$1000, it time to start porting.

Seriously, I would rather have good aftermarket heads on a 351 than stock or even ported W castings on a 408.

Look at the flow requirements and valve sizes of all the other engines, regardless of MfG. on an engine of 400 cubic inches or better. I guarantee none of them will have 1.68 (or whatever it is) exhaust valves like the W castings, and all will have an exhaust port bigger than your thumb.

You might as well put a governer on the engine, as that what the W castings will be.

If money is the issue, wait and save. Or put it on a card and make payments. Don't throw money down the drain now and have to do it over two years from now. You can find used performaer RPMs or something like them for $800 if you are patient. You will never regret it.

69Tool · Jun 18, 2007

So would a set of Edelbrock RPM Performer heads be a good recommendation? If so, I will keep my eyes open for them. I have enough time before the car is ready to save for $800 to $1200 for a set of heads. Perhaps something like this? http://www.jegs.com/webapp/wcs/stores/servlet/productitem_10001_10002_744623_-1_69894?CT=999

dodgestang · Jun 18, 2007

Well....seems like I must be the only one who wants to break with forum (group) think here.

You don't need a stroker for what you want. Just build a nice 351 back to stock, maybe add a nice cam and an intake and you will have a zippy motor with more than enough power to light your life up on the weekends. You don't need to sink money into a new crank and rods and pistons just to have a strong running motor. If the motor needs to be rebuild have a good machine shop do the rebuild. Most likely all they will need to do is clean up the crank a little, maybe bore the cylinders a bit to clean them up, press on new pistons, and button it all back up.

My old 67 fb had a 351w with stock heads, a cam, 4.11 rear and a c4 and was an absolute blast to drive and to me it was fast. My 410c is obviously faster than the 351w ever was, but it hasn't been able to replace all the great memories I have of that car. I was able to get in it, and drive anywhere and time. It didn't have so much power that it was dangerous to drive it bad weather because of how easily it could overpower the tires, but at the same time it could smoke through 2nd if I wanted to.

bnickel · Jun 18, 2007

Nick, actually i did mention staying with the stock displacement on another forum he and i are both on. i think he's pretty much set on the stroker, his last mustang was a 390 GT car so i'm guessing he just wants the extra cubic inches.

69Tool · Jun 18, 2007

bnickel said:
Nick, actually i did mention staying with the stock displacement on another forum he and i are both on. i think he's pretty much set on the stroker, his last mustang was a 390 GT car so i'm guessing he just wants the extra cubic inches.

Bnickel is correct, I really want to have that extra power, but without building a race car. I want to do it since I have to have the whole thing rebuilt right now anyway, while the car is apart. Therefore, I started to think stroker. However, as people have pointed out, it is a costly endeavor, so I want to try to split the difference somehow. Ratio suggested the idea of the 393 crank with the 302 pistons and that appealed to me on a couple of fronts, 1 being it is a cheaper alternative, and 2 being that it will have more performance than a stock build. Therefore, I am trying to gather more information about the 3 options. I am currently pricing out the ideas based on feedback from everyone. I really appreciate the input from everyone, and I am doing some research on cost, machine shops, etc. Again, thank you for everyone's input.

bnickel · Jun 18, 2007

you might seriously consider using some iron Windsor Sr. heads and the 392 stroker, you'll still save money over the 408 stroker kit even with the heads and they will out flow stock or mildly ported 69 351w castings.

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