Stroker Block Questions

[4barrel]

Ok, so I'm new to the Ford scene. I have a few questions about building a naturally asperated stroker engine that will have a carb and it will be used for the street and the strip. On to the questions. Will a stock 302 block be strong enough? What prep does the block need to be ready for a 347 rotating assembly? What prep for a 331? I have heard simply boring the block thirty over will do the job, but I have also heard the crank will rub unless you notch the block. Help me out with any information that you can about building a stroker, I appreciate it.

[Fat0eknee]

bottom of the cylinder sleeves will need to be notched to clear the rod bolts ...id also go with a 331 over a 347

[~The Jester~]

Funny you should ask that, I just built my 347 shortblock today. A stock 302 block will be strong enough if you don't get to crazy with it. There's alot more weight swinging around in there, and it's swinging alot farther to boot! I HIGHLY recommend a stud girdle. In fact I wouldn't build a stroker without one.

Block need notched at the bottom of the cylinder bore to clear the rod bolts, so does the girdle. For both the 331 and the 347. You would not believe HOW CLOSE the crank throws are to the bottom of the pistons!!!! Also, now that I've had one apart, DO NOT buy stroker pistons that have the wrist pin down in the oil control ringland. Could give a poop about burning oil, but that situation causes some serious problems that I just found out about today. Stay away from those.

331 vs. 347? I'd go with the 331 given a choice. Less weight/arm/strain on that block that was only supposed to have 255 hp from the factory. 331's absolutely SCREAM, and we have one making 550 (flywheel) ponies, although it's in an SVO block.

Good luck, and let us know how it goes!

[4barrel]

I suppose any machine shop can take care of notching my block for me. Thanks. I always heard a 331 would make just as much power as a 347. I don't understand how that's possible, but I'm new to the Ford world. I appreciate the quick replies.

[Ieatcamaros]

A hand grinder will take care of the block notching for you. Just do it and then clean it out before you assemble your motor.

[~The Jester~]

.060" MINIMUM on the block clearance. .080" MAXIMUM Then tear her apart, clean the shyt outta her, put her back together!

Watch the cam lobe clearances too. You'll see what I mean when you put it together. Big Nasty cam lobes hanging down, whilst big nasty crank lobes are pointing UP, could be a problem. Watch the rods here, rod BOLTS down below. Watch the bottom of the pistons at the bottom of the stroke too, they are SOOOOOO close to the crank throws, it's not even funny. Kinda scary actually. When ya put all the big nasty shyt in a small block, it get's REALLY close all the way around. Watch for stupid stuff, things you never thought would hit, ARE GONNA.

Don't be scared. Noones lookin. Stroke it.

We'll help you out along the way bro, just build the darn thing.

If you build it, they will come!

[andy669]

When comparing 2 engines that are identical, with the exception of 16 more cubes via stroke, the bigger one will make more power. Of course compression height is going to change if you were to use the same rod for each, but going from 1.100 to 1.175 would make no noticeable difference. The HP gain would be strictly from more cubes.

Andy

[~The Jester~]

1 STROKE cube is worth 2 in the bore.

[4barrel]

Ok I have another question or two. What are the possible combinations for the 347 and the 331 as far as poke and stroke go...less stroke, more over bore...short rods, tall pistons...etc? Which would be best for a 331 and for a 347? Sorry for the trouble. I really like to research this stuff before I start into things. Who better to ask than the Mustang Works gang...

[procharge94]

4barrel, I have a question for you. Are you planning on stroking a 302 block you currently have possession of or purchasing a block to stroke? If you are purchasing a block, my preference would be to step up to a 351 block. The 351 has larger main journals and is a stronger block all around. I'm sure I will be stepping on some toes by recommending a 351, but its worth considering if you are going to be starting from scratch. And if you really have the itch to stroke a motor, stroke the 351 to a 392, or even a 408.

[andy669]

The most common 347 is a 3.4 crank with a 4.030 bore. The most common 331 is a 3.25 crank with a 4.030 bore. Most companies use a 5.400 rod, but I have seen some use a 5.315. On a normal street motor, it will make no difference.

If you want a 331, I have a 3.25 4340 forged crank for sale. Its in excellent condition.

Andy

[4barrel]

Well that was a thought also. There are some stock 302 blocks around the shop that I can get for free and are in great shape. If I go with a 351 block I'd have to buy a block. I've looked around and they're not easy to find around here, but I'm guessing I haven't looked hard enough. I would like to stay with a 302 for a few other reasons too. Would a 408 be overkill for a street/strip car? Also, not that cost is too much of the issue, is a 302 less expensive, easier to find parts for, and alot easier to work with? I still have a 408 or a 410 in the back of my mind. Before I bought a Mustang, I had said that it would get a 408 but my "stang gang" have talked me out of that.

Not to ask dumb questions, but what height pistons and what wrist pin positions would go into a motor with the most common stroker set ups?

[rwhite65]

The 351 Block is gonna be heavier and stronger. Parts are about the same for the two, since a lot of it does interchange. The question here is how fast do you really want to go?

Andy669, if you still have that crank and no one else wants it, that may find a nice home in my garage......
Ryan

[procharge94]

I would not say that a 408 is too much for a street car. If you build the rest of the car accordingly, the extra power will just make driving more enjoyable. Its like rwhite65 said, "how fast do you really want to go?"

Parts are interchangable and costs are roughly the same as well. Cost, part availability, and interchangability are not going to be an issue with a 351. Finding parts for a 351 stroker motor as just as easy as finding parts for a 302 stroker motor.

[4barrel]

Well since I am in the planning stage still, lets talk 351 based engines. I hear a mid 90's Lightning roller block was very good. How true is that? How hard are they to come by. If it's not worth it, what block should I get? What cubic inch do you recomend and what would the block need to be prepped for that? Thanks for the time fellers.

[rwhite65]

Well, I personally would like a newer 351w block out of a mid 90's bronco or something, cause they are suppose to have roller cams in them. though the new blocks are not as heavy as the old ones, they are also said not to be as strong as the old ones. But, throw a main girdle on it, and most durability issues are solved.

I believe one of the stroker combinations (392..or maybe a 396??) uses ford parts except for the crank. Truck rods and 302 h.o. pistons are used in the combo if I remmeber correctly. The car sitting in my garage has a 408 in it, and even though we are ironing out some timing issues, the thing screams. It is fast enough it has me thinking of putting one in a 89-93 next summer.

hope this helps,
Ryan

[Dark_5.0]

Originally Posted by andy669

The most common 347 is a 3.4 crank with a 4.030 bore. The most common 331 is a 3.25 crank with a 4.030 bore. Most companies use a 5.400 rod, but I have seen some use a 5.315. On a normal street motor, it will make no difference.

If you want a 331, I have a 3.25 4340 forged crank for sale. Its in excellent condition.

Andy

How much????

[4barrel]

Back to the 331...Will a stock flywheel and balancer do the trick or will that need to be upgraded too?

[andy669]

$300 plus shipping. Lemme know I can get you some pics. I have the balance info too.

Yes, the stock flywheel and balancer would work fine for the 331.

Andy

[4barrel]

What are you guy's opinion on Scat brand internals? I've found a pretty good deal on a forged stroker kit from Scat. Also, a stock flywheel will work, but what would the advantage of an aluminum flywheel be, and would it be worth the price or just a waste of money that can be spent on other "go fast" parts?