scouttrooper

I've been curious for a while now. How do they feel? Great low end, or better high end or both? Sacrifices? What do you lose when you stroke a motor? Start OK? Idle just fine? Do they require cams that make them lopey? Are their reasons we don't all stoke motors when we do a complete rebuild? I'm sure the mileage sucks. My 302 is a lot of fun, and I'm probably not changing anything anytime soon, but the devil over my right shoulder keeps chanting "more-more-more."

ldollar

haha, that devil will never leave you alone!

all i have ever had was a 347 stroker and i LOVE it. but I bought the car like this so I cant say what the difference is. Yes the mileage is not good but if its not a commuter car, who cares? The power is pretty incredible as far as I am concerned. Of course there are more powerful cars around but this thing has a lot of torque and so far I have not had anyone beat me off the line on the street. But I dont go out looking for races either. That is a good way to get shot around here.

I guess from what I can tell, if all your numbers are matching, I probably would not stroke. If you are restomodding and you have the cash to stroke it, i would do it if you are going to rebuild anyways. This engine is a LOT of fun. Big block power in a lightweight small block. Just make sure it is done right. The P/O of my car spent over $8k on the stroker and rebuild and everything was done right. It was done at an engine rebuilders company in San Francisco. I am sure you could probably do it cheaper but I would talk it up with your local pals who have done this before and make sure it is done right so you dont F up your perfectly good 302.

And to answer your questions... Mine starts perfect every time. At idle, she purrs like an angry cat and turns heads without even revving the engine. She just itches to drive fast. Hopefully some folks on here with a little more experience of the pros/cons will chip in since I can only tell you one side of the story.

Daze

As far as drivability a stroked motor is effected by all the same things as any other motor build up like fuel delivery and came size. How you build it effects how streetable it is and at what RPM it functions best. Stroking a motor has two main negative side effects, the first is a lower redline RPM. Think of it like this if a piston normally travels 4� per stroke and you add .5� to said stroke, the extra stroke is extra distance the piston has to travel both directions every single rotation of the motor. (These numbers are made up to illustrate) If the normal stroke of a piston is 4" and the max RPM in 6000 the piston travels 8" per full stroke or 4000 feet per minute if you increase the stroke by .5" that 8" becomes a 9 (4.5" up and the same back down) which calculates out to 4500" per minute and in theory would be 500' per minute over the theoretical max. If you calculate it backwards if a 4" stroke had a max RPM of 6000 than the 4.5" stroke would have a max RPM of 5333. The second problem with stroking a motor is reduced life, that extra distance in stroke causes the rings to were faster. A .5" increase of a 4" stroke is a 12.5% increase, and translates to the rings wearing 12.5% faster, so if rings are normally good for 100,000 miles than with that increase the rings will be good for 88,900 miles. To add to this problem the extra stroke happens at the bottom of the cylinder and typically part of the piston comes out of the cylinder, as this happens the piston can more easily move side to side which wares the piston walls faster at the bottom. All that said you shave off at least 25% of a 302’s life by stroking it. This is not true for all motors. The 302 started out as a 221 and then changed to a 260, 289, and 302 by increasing both bore and stroke. In the pursuit of minting normal motor life the 302 motor was maxed out for bore and stroke by Ford and that is why the block got a little bigger for them to make the 351. On the flip side the 351 never had any other increases in size that is why a 351 can be stroked out to a 393 with out causing any shortening of the blocks life. It is when you stroke a 351 out to a 427 or 460 that you run in to the same pit falls a stroking a 302 out to a 347. Now don’t get me wrong I am not saying don't stroke out a 302, I am simply telling you that the extra power comes at the price of a shorter motor life. If the car is simply a weekend warrior than why not stroke it out because it will take forever to get any miles on the car, but for a daily driver you will be racking up miles and will need to be replacing the motor sooner if it was stroked.

ldollar

+1

Personally I dont expect to put more than 5-7000 miles/year and my stroker has about 18k on it now. I figure with relatively conservative driving and excellent maintenance, I should be able to get at least 100k out of my 347. (I have heard of some people getting over 150k out of their 347...I dont expect that kind of mileage because I don't drive like Grandpa but hey, it CAN be done.)
Even if I drive 7000 miles/year, it would take me over ten years to get my odometer to 90k miles, starting at my current 18k.
That is not too bad.
If it goes sooner, oh well. It was fun while it lasted!
I will just have to buy another one!!!

Daze

I agree, how you drive it and how you maintin it will make all the difference in the world Bottom line is that if you dont change the oil and run a 302 hard and then treat a 347 the same way the 347 will need to be replaced sooner, sme applies with a well maintained motor if you can get a max life of 200,000 miles out of a well maintained 302 in theory you will ony get a max life of 150,000 out of a well maintained 347.

"If it goes sooner, oh well. It was fun while it lasted! " Good attitude I have always lived by the idea of it you have it drive it and have fun, and if it brakes fix it, and have fun

Starfury

Well, I bought my 67fb with a rebuilt (80k mi on the rebuild) C code in it. No real problems with it initially, but upping to a 4V carb helped throttle response and high end power a little. Then after it started running rough and fighting with it a little, I discovered it was running on 6 cylinders, so time for a rebuild.

I went almost all-out on the rebuild, 331 stroker lots of other go fast goodies.As Daze mentioned, stroke (or more importantly rod ratio/angle) can affect ring life, so I chose the 331 over the 347 to reduce rod angle and increase reliability. I completely overbuilt the bottom end though, ARP bolts everywhere, main studs and stud girdle (although I recommend against a stud girdle unless you're pushing >450hp; mine's pointless and a pain in the ***), forged rods w/cap screws, hypereutectic pistons (lighter and cheaper than forged), full floating wrist pins, etc.

This is what I'm running with right now:
Edelbrock 600CFM carb
MSD ready-to-run distributor (no box)
Comp Cams Magnum 280H cam
Rhoads lifters
Exhaust port-matched '68 heads (9.3:1 CR w/63cc chambers)
1.90/1.54 valves
Screw-in studs
Roller rockers
Comp Cams double valve springs and pushrodguideplates
Full length headers, dual 2-1/4" pipes w/H-pipe, Flowmaster Hushpower II mufflers
3sp m/t, 3.25:1 open rear
Guesstimated 320hp, 330ft-lbs net at the flywheel

I absolutely love it. I'd really like to have a 4 or 5sp and some shorter gears, but it still takes off like a rocket as is. The Rhoads lifters provide goodtorque from 1500 to 3k, and the cam takes over from there and winds all the way to 6k+. It's much more torquey down low than it used to be, even with the aggressive cam. With a Powermaster mini-torque starter and modern ignition it fires up the first time, every time. It has a very mild lope at idle thanks to the Rhoads lifters (it would be downright mean with standard hydraulic lifters). It pushes about 12mpg city, ~15mpg freeway (guess, haven't calculated yet), which is up from 8/14 with the XE268H and standard lifters I yanked out a couple months back.

As Daze said, a lot is just how you build it. If I wanted to build mine into a 450hp unstreetable monster, I could have. But I have to drive my car every day, so I built it streetable, but aggressive. I could've done the same with a 289, butit was much easier to make a streetable 300+hp with the stroker. And I like to overdo things, and 40 more cubes sounds like a good way to do that

67mustang302

Yeah, all good info. Other disadvantages to a stroker are they tend to have worse rod ratios(the length of the rod divided by the stroke). It causes the piston to be pushed harder against the cylinder wall, especially at the bottom of the stroke, causing the cylinder to wear out of round faster, and also increasing ring wear along with the increased stroke length. It also reduces piston dwell which has a negative effect on combustion, so they burn fuel less efficiently than an engine with a longer rod ratio. Strokers generally tend to make more power at a lower rpm(all things being equal of course) but do so at the cost of reliability and efficiency. Also, because the crankshaftstroke is longer, it places greater stress on the crankshaft and main webs(the weak point of a 302). All things being equal, a 302 will take more power before breaking than a 347(in most cases).A lot of it is really in the build and the maintenence though. A 347built with high quality parts that's well maintained will last longer than a cheap 302 that gets no maintenence.

To give an example of shorter stroke efficiency, Formula 1 engines are about 145 cubic inches, and have a rod ratio of around 2.2 or longerI think(VERY long rods for the engine, which is completely obscene) and they turn 19,000rpm at peak, producing around 700-750hp NATURALLY ASPIRATED!!! That's around 5hp per cubic inch, all engine. They have less than a 2" stroke. Several years ago with less restrictions they had 180cid V10's making over 900hp.

Strokers have advantages, but they also have disadvantages. Stuff to consider before you build one. Shorter stroke enginesare also easier to keep compression down onand more forgiving of supercharging and turbocharging

superdavid

I love strokers, and my 408 is still driveable enough that I drove if from Texas to Califiornia and back. Torque is EVERYWEHRE!!!! Its so much fun! Just make sure the rest of your drivetrain can take a real thrashing...
[sm=burnout.gif]

66JameStang

+1
There is nothing like the torque i have felt from my strokers and you can bark the tires an any gear

JMD

How do strokers differ from non-strokers in terms of feel?

My son's 408 feels like a wolf in sheep's clothing....

Or as it is, a big block in a small block package....