This weekend at Morris Mtn I blew up my 351w. Still haven't torn it apart, but there are holes in the oil pan which leads me to believe it threw a rod/something fatal. It happened while I was trying to avoid a rollover (which I was unable to do). The motor is a '72 block, and from what I've researched, this block is favorable because it has some extra meat.

My questions is what's the best way to build a reliable propane-injected 351w that puts out ~325hp. I'm limited by my impco 425 which puts out ~460cfm. If my block is salvagable, I was toying with the idea of stroking it to 393 or 408. I plan on re-using all of my accessories and my Weiand Stealth intake. The max I would like to spend is $3000. If the block is or isn't salvagable, what are some recommendations?

I'm not sure about the propane system, but I'm building a 95 block labeled F4TE which is a stock roller motor. Very nice revving engines. Find one of those with your propane, etc. and it should be a sweet setup. Just my advice.

I don't see you getting 325hp with the Impco 425, especially on a 393 or 408W.
There is an adapter that would allow you to run dual Impco 425s . . .

If you're going to up the displacement, I would recommend upgrading the heads, intake and camshaft.

Something in the 400 CID range can easily handle .500" lift and 260*+ duration without too much fuss.

On your block however, I give it a very low possibilty that it made it out as economically salvagable. Typically the damage you see on the outside is double that on the inside, so it wouldn't surprise me to see the bottom of the stock bore broken off along with many other instances of internal carnage. I would strongly advise buying a new block.

Your number one purchase should be an oil accumulator. That prevents a lot of oil starvation at extreme angles.

X2 on the roller block. They will withstand 400hp all day and are becoming more reasonably priced. Look for 94 and later truck engines for these blocks. You can use the Mustang roller cams in these engines. They rev nice and make more/better power than a flat tappet. X2 on the accumulator as well, i've seen them save several engines when the rubber goes up!

A 351W is a fairly tough engine in my experiences. If you HAD to pick a weak link on them, it would be the rods. ARP rod bolts and a rev limiter have always been part of my Windsor builds. If you are looking for maximum airflow, you need to seriously look into aftermarket heads- I like my Twisted Wedge heads on my stroker mill.

I think I've decided to hold off on stroking it (since I'm only pushing 460cfm). ~325hp should be plenty in my mind (for now). I was looking at some 165cc AFR heads, and then just building everything else fairly mild. Thoughts? How much is a roller block?

x3 on the accumulator, i hit 8000+rpm in mine and spun #3 rod bearing. now adding one to hopefully prevent that a second time!!!

Well, I'm not sure how much I can help you since your running propane (a BIG power killer IMO), but here's the specs on my 351W build:

-'78 351w block, .060 over
-Stock crank, rods, caps, all ARP fasteners
-Speedpro hypereutectic pistons, 9.25:1CR
-E7TE heads, ported, polished, bowl blended
-Crane roller rockers, 1.6 ratio
-Comp Extreme 4x4 cam, 250/258 duration, .477/.493 lift
-Edelbrock Performer intake
-topped off with Q-jet, Shorty headers, Proform HEI

300hp, 410lb-ft

$2300 including machine work.

Well, I'm not sure how much I can help you since your running propane (a BIG power killer IMO), but here's the specs on my 351W build:

-'78 351w block, .060 over
-Stock crank, rods, caps, all ARP fasteners
-Speedpro hypereutectic pistons, 9.25:1CR
-E7TE heads, ported, polished, bowl blended
-Crane roller rockers, 1.6 ratio
-Comp Extreme 4x4 cam, 250/258 duration, .477/.493 lift
-Edelbrock Performer intake
-topped off with Q-jet, Shorty headers, Proform HEI

300hp, 410lb-ft

$2300 including machine work.

Is that dyno #'s? Or are you still throwing out the DD #'s?

Is that dyno #'s? Or are you still throwing out the DD #'s?

DD, its the best I got. There are no dynos within 100mi from here. Honestly, numbers don't mean much as they are only a means of reference, seat of the pants performance where its at. With that being said, and for those that don't care about numbers:

This motor hits harder than the stock 460 in my other truck, which gives me an idea its making decent power. It crawls the truck anywhere I want it to go, at 500rpms, and spools up the tires almost instantly off road. Its fun to drive on road, provides nice acceleration, and turns over the tires at will. However, it lays down at 4500rpms due to the cam, so its no screamer, just a good low end torque motor. That's my best description for those that doubt numbers, or those that realize numbers don't always equal reality.

Vertical hit upon something with the propane-

If you a re FOR SHURE going to run propane, and NEVER go back to pump gas, then build the engine with a higher compression to regain the power loss from running propane, and run ignition timing that has faster advance.

DD, its the best I got. There are no dynos within 100mi from here. Honestly, numbers don't mean much as they are only a means of reference, seat of the pants performance where its at. With that being said, and for those that don't care about numbers:

This motor hits harder than the stock 460 in my other truck, which gives me an idea its making decent power. It crawls the truck anywhere I want it to go, at 500rpms, and spools up the tires almost instantly off road. Its fun to drive on road, provides nice acceleration, and turns over the tires at will. However, it lays down at 4500rpms due to the cam, so its no screamer, just a good low end torque motor. That's my best description for those that doubt numbers, or those that realize numbers don't always equal reality.

I wasn't trying to be an ass (for once), was just curious if you had gotten it dyno'd.

Propane is 110 octane so a compression ratio in the 10-1 to 12-1 range will gain back some of the power vert mentioned losing. Also your dizzy needs to be curved for pane, it's much different. Research different cam grinds especially for propane. I believe if you do your homework and build it right it will have more power than comparable gas engine and run upside down at 300 rpms :D.

Vertical hit upon something with the propane-

If you a re FOR SHURE going to run propane, and NEVER go back to pump gas, then build the engine with a higher compression to regain the power loss from running propane, and run ignition timing that has faster advance.

Anyone recommend a place to buy a short block? I plan on re-using all of my accessories and my dizzy. I was thinking about tracking down some GT-40 heads to go with it. I know Jasper may be a little pricier than others, but anyone have any good leads?

I had a jasper in an 86 f-250 I had. I beat the living shit out of it and never had a problem. The again I only put 9K on it before it lit on fire.......

Anyone recommend a place to buy a short block? I plan on re-using all of my accessories and my dizzy. I was thinking about tracking down some GT-40 heads to go with it. I know Jasper may be a little pricier than others, but anyone have any good leads?

I'm assuming you mean a stock short block, in which case you are throwing your money away. You will be stuck with cast pistons likely of lesser quality than OEM, a compression ratio of between 8.5 to 8.8:1, and probably a poor quality assembly overall. Buy a junkyard long block for $200-300 or so, and build it yourself, a lot more bang for your buck.

As for the GT 40 heads, good luck. I spent at least two months scouring every source I knew trying to find a set, to no avail. OEM GT 40 and GT 40 P heads are getting very hard to find, and as such people are charging more than they are worth for them. If you know what your doing, you can take a stock head and work it over to make good power for very little coin. There are a couple stock castings that are better than others for heads, but like the GT 40's, the good ones are getting hard to find. I purchased several OEM castings to compare and decided to go with the E7TE truck heads. There are better ones out there if you can find them, such as the early Boss heads (C9 casting IIRC), but I couldn't find a set. Some people like the E5AE heads, but I with a little touch up I saw no advantage of these over the E7TE truck heads (which are cheaper and more common.) If you want to spend a little money and not do as much work yourself, try a set of World Jr 180 iron heads, about $800 a pair assembled.

I've considered going the self-build route, but I'd prefer to have some sort of warranty. I know Jasper offers a 3-yr. Since I'm only running a single impco 425, I'm not going to build a 350+hp motor. I'm looking for something around 300-350hp. Going to limit it at 6000rpm. I figured I could achieve that with a basic short block and decent heads.

I am anxious to see what you decide and how it works out for you. Here is one I found that sounds about right:http://www.mustang50magazine.com/techarticles/86598_central_coast_mustang_high_performance_engin es/index.html
High compression, decent price, sounds good but I have never heard of the company.
Really I am looking for someone to build my HO 302 in trade for kitchen cabinets(thats what I do) but no such luck locally.
Check with the mustang sites, there are a ton of classifieds mustang specific it is just a matter of finding something not to far away.

Little bit off topic, and not to hijack, but rather than starting a whole new thread......maybe one of ya can help me and maybe some others real quick.....whats the max. you can safely bore and stroke the 351W engine? By safely I mean, to the point where you're not weakening the block, etc. Reason I ask is because I just picked up an 87 F350 with a running 351W in it and am considering maybe buildin a stroker out of it in the future. Also, anyone know if this is a decent block to start with for a stroker build....the one out of an 87? Sorry if I hijacked it, but maybe this'll help the poster too....idk.

Zach

I'm assuming you mean a stock short block, in which case you are throwing your money away. You will be stuck with cast pistons likely of lesser quality than OEM, a compression ratio of between 8.5 to 8.8:1, and probably a poor quality assembly overall. Buy a junkyard long block for $200-300 or so, and build it yourself, a lot more bang for your buck.

As for the GT 40 heads, good luck. I spent at least two months scouring every source I knew trying to find a set, to no avail. OEM GT 40 and GT 40 P heads are getting very hard to find, and as such people are charging more than they are worth for them. If you know what your doing, you can take a stock head and work it over to make good power for very little coin. There are a couple stock castings that are better than others for heads, but like the GT 40's, the good ones are getting hard to find. I purchased several OEM castings to compare and decided to go with the E7TE truck heads. There are better ones out there if you can find them, such as the early Boss heads (C9 casting IIRC), but I couldn't find a set. Some people like the E5AE heads, but I with a little touch up I saw no advantage of these over the E7TE truck heads (which are cheaper and more common.) If you want to spend a little money and not do as much work yourself, try a set of World Jr 180 iron heads, about $800 a pair assembled.

the Gt40s are harder to find, but they are out there. Look for '96 and later Ford Explorers with the 5.0s in them. From '96 to mid '97, GT40s were used, from mid '97 to the end of the 5.0 GT40ps were used. I found a set for a buddy a few months ago still on a wrecked exploder. He paid $100 for the pair. Slap on a Trick Flow valve spring upgrade kit from Summit, some roller rockers, and drill the bolt holes out to accept the larger 351w head bolts and you are done. The Ps are the best factory flowing iron heads available. No granted, they are not going to flow like a set of AFRs or TrickFlows, but they are right up there with a set of Eddy Performers.

I've considered going the self-build route, but I'd prefer to have some sort of warranty. I know Jasper offers a 3-yr. Since I'm only running a single impco 425, I'm not going to build a 350+hp motor. I'm looking for something around 300-350hp. Going to limit it at 6000rpm. I figured I could achieve that with a basic short block and decent heads.

Lets say you find a good factory short block for the price you want (which you know comes with the pistons, rotation assy, and cam), and put on the best set of SBF heads out there, along with your propane setup. You can't change anything in the bottom end, because that would void the warranty you wanted. This leaves you with stock pistons and a stock cam. I would bet good money that you will only be making about 270hp or less, and it probably will only spin 4500-5000rpms max.

Here's why, a good running motor needs to have all of its components matched to the intended application. With the setup you suggest, you will be limiting the intake to 460cfm, then inducting it into a set of heads that are meant to flow huge CFM #'s, thereby killing your port velocity. The stock cam is also working against you here, as is the low CR, propane, etc. Hmmm, that sounds an awful lot like a stock 351M...and we all know the beastly hp numbers they put out stock, lol.

Go ahead and spend big $$$ on a set of heads if you want, but you will be getting no where near the power numbers you want. Spend the money on a well matched setup, build it yourself, and forget about the warranty, and you'll be much happier in the long run. That's my advice, take it or leave it.

Little bit off topic, and not to hijack, but rather than starting a whole new thread......maybe one of ya can help me and maybe some others real quick.....whats the max. you can safely bore and stroke the 351W engine? By safely I mean, to the point where you're not weakening the block, etc. Reason I ask is because I just picked up an 87 F350 with a running 351W in it and am considering maybe buildin a stroker out of it in the future. Also, anyone know if this is a decent block to start with for a stroker build....the one out of an 87? Sorry if I hijacked it, but maybe this'll help the poster too....idk.

Zach

.060" overbore, 3.85" is pretty safe on the stroke IMO, but you can go bigger.

I hear ya. Since I'm only gonna flow 460cfm, I'm not going to spend a hell of a lot of money on free-flowing heads. What do you think about this spec sheet?

http://www.jasperengines.com/pdf/Class-II-Ford-351-305-hp05.pdf

I hear ya. Since I'm only gonna flow 460cfm, I'm not going to spend a hell of a lot of money on free-flowing heads. What do you think about this spec sheet?

http://www.jasperengines.com/pdf/Class-II-Ford-351-305-hp05.pdf

Looks like a decent setup, if you go that route I would swap on a set of roller rockers, they'll free up a little more power and keep the oil temp down.

Looks like a decent setup, if you go that route I would swap on a set of roller rockers, they'll free up a little more power and keep the oil temp down.

Vert will vouch for this: SPEND THE MONEY TO HAVE THE HEADS DRILLED FOR SCREW IN STUDS INSTEAD OF USING PEDISTOOL MOUNT ROCKERS!!!! It makes valve adjusting/maintenance much easier and will save you some coin when it comes to buying the rockers.

Vert will vouch for this: SPEND THE MONEY TO HAVE THE HEADS DRILLED FOR SCREW IN STUDS INSTEAD OF USING PEDISTOOL MOUNT ROCKERS!!!! It makes valve adjusting/maintenance much easier and will save you some coin when it comes to buying the rockers.

Ordinarily, yes, I would suggest screw in stud type, and I will go that route on my next set of heads. However, in his case (wanting to buy a crate motor due to warranty) pedestal mount roller rockers would suffice. Machining the head for the screw in type would be ideal, but I'm sure it would void the warranty, whereas the pedestal type could be taken off if there was trouble.

I keep flip-flopping back and forth. Now I'm talking to a buddy about buying a 393 or 408 rotating assembly and just getting my oem heads re-worked (due to the 460cfm carb). I could up the compression a little bit and put an rv cam in it. The engine on the spec sheet is $3000 to my door. My buddy claims we can do it for less, but I'm a little hesitant. I guess the first thing I need to do is get the motor out and see if the block is salvageable

I keep flip-flopping back and forth. Now I'm talking to a buddy about buying a 393 or 408 rotating assembly and just getting my oem heads re-worked (due to the 460cfm carb). I could up the compression a little bit and put an rv cam in it. The engine on the spec sheet is $3000 to my door. My buddy claims we can do it for less, but I'm a little hesitant. I guess the first thing I need to do is get the motor out and see if the block is salvageable

This has sortof been my plan al along after I found this roller 351w. I was planning on picking up a 393 or 408 rotating assembly and having a local builder machine the block and assemble it for me. Then I could just take aluminum heads, cam, and EFI stuff off my existing 302 and swap it on. It would be a torque monster with cam and smallish heads, but that's really all I am after at this point. I like the 302 for it's reliability and great manners on the trail, it just has ZERO torque down low and really struggles to keep things moving on the highway. Even with 5.13s, I spend a lot of time in 2nd gear just to maintain highway speed on the hills.

Heck, I don't know at this point. I just bought a set of 42in Iroks. I am going to have to up the power now. I was thinking of cramming two small T3 turbos under the hood, but tuning would be a nightmare. A low compression (so that it will run on pee gas) 393 or 408 sounds better at this point. I just want to be able to drop it in and forget about it. And it has to be easy to keep cool too.

I've said it before an I'll say it again. c-6's are too HP robbing for 302's.

I keep flip-flopping back and forth. Now I'm talking to a buddy about buying a 393 or 408 rotating assembly and just getting my oem heads re-worked (due to the 460cfm carb). I could up the compression a little bit and put an rv cam in it. The engine on the spec sheet is $3000 to my door. My buddy claims we can do it for less, but I'm a little hesitant. I guess the first thing I need to do is get the motor out and see if the block is salvageable

If your block is salvageable, build it. Here's a build you might like:

-Scat 393" rotating assembly: forged pistons, forged rods, cast crank, 12:1 CR, $925
-Machine work for bottom end, don't know how much it will need, but budget at least $900 (you'll have to get the rotating assy. balanced)
-ARP rod, main, head bolts, $150
-OEM oil pump, gaskets, cam bearings, $100
-Comp Extreme 4x4 valvetrain kit (w/ 262/270 duration, .493/.512" lift cam), $435
-Roller rockers, $200
-head machine work/valve job, have heads cut out to 1.94/1.54 valves (including SS valves), install screw in studs for rockers $500
-port, polish, bowl blend, $20 (for supplies, you do this part)

Total including a little extra for misc. stuff, $3500, you could do it for less if your thrifty.

Should be around 350hp/450lb-ft on propane, vs. probably 275hp/375lb-ft for the jasper crate motor on propane.

I've said it before an I'll say it again. c-6's are too HP robbing for 302's.

no argument there. It probably sucks up about 40hp of the 285hp my 302 makes, even with the wide ratio gears and roller thrust bearings. But running a C6 allows for room to grow power-wise, which was the plan all along. :D I built this trans to handle anything I can bolt in front of it, and I intend to take advantage of the strength in the future.

anyways, back on track.

.060" overbore, 3.85" is pretty safe on the stroke IMO, but you can go bigger.

So if ya did this stuff to a stock 351W.....what is your displacement after it's all said and done? Is it like 408? I know very little about modifying motors and whatnot....just basics. Also, I found this...

http://www.perfeng.cc/engines.html

They're all very expensive setups, but just an example....How do the 351 W blocks like the one I have out of an 87 F350 hold up to that much boring and stroking like on the setup they have that says

"427 Windsor Stroker • 565 HP"

????

Zach