BigMike80

Let me first appologize for my newbie questions. I am a bit confused on what it means to stroke and bore an engine. I sort of understand what it does but what Im unsure about is the pros and cons of this. What would I gain out of a stroker engine vs a non stroker? Same question for a bored engine? How about to bore and stroke an engine?

I also keep seeing 427/454 or 429/460 when Im looking around for crate engines. Could someone explain to me what these 2 numbers mean? Also if anyone has some good resources that I could read up on to learn more about engines I would appreciate it.

Thanks for any info you guys can give.
Mike

67mustang302

Bore is the diameter of the cylinders and stroke is the length the piston travels from the top to the bottom, combined with the number of cylinders is determines displacement. A stroker changes the crank/rods/pistons so the same block can be used, with basically the same bore, but the stroke is longer, for example a 302 is a 4" bore and a 3" stroke, a 347 is a 4.030" bore and a 3.4" stroke(a 342 is the same with a 4" bore even, still people refer to it sometimes as a 347 though). The quick lowdown is this....bore size determines piston surface area, the larger the bore the larger the surface area, it's that surface area that combustion pressure pushes on, so the same pressure exerted over a larger area makes more power, but it also makes the pistons heavier when compared to a smaller bore, which can put more stress on the rotating assembly at high rpm(using good parts generally makes this a mostly non-issue). A longer stroke means there is more time for the air and fuel to burn and exert pressure on the piston, so it makes more power, but the longer stroke is better able to make power at a lower rpm, so a longer stroke engine makes more power than a shorter stroke engine, and also makes it at a lower rpm. The longer stroke also means higher piston velocity, which has a much larger impact on high rpm stress of the rotating assembly, this can be somewhat reduced by the use of high quality parts, but longer strokes put much more stress on the rotating assembly and the block, since it changes the rod ratio which effects piston side loading, and the longer stroke leads to a crank that flexes more, it aslo changes the rod angle and increases stress on the main webbing of the block. Even though all that increases stress at higher rpm, a stroker doesn't need tp turn high rpm to make power, so it's sort of a tradeoff.

As far as crate engines, when you see something like 302/331/347 that means it's a 331 stroker or a 347 stroker built of a 302 block, usually the engine is available as a 302, a 331 or a 347 option.

mat11089

Its nice because u can get higher cubes out of a small package such as 351 to 428 and what not.Big block cubes with small block weight and size

BigMike80

If this were going to be a mustang to be driven but not raced what would be the best route to go? From the description above it sounds like a bored out engine would be a better option than a stroker in terms of performance and life expectancy of the engine. Am I correct with this assumption? If not could someone please let me know the best route to go if I want a car that is a sort of weekend warrior (something that will be driven but probably not raced very often if ever).

mustanglover66

For the basic cruzer I would only do what the engine needs and only bore it if there is to much wear in it to hone standard. that way you can freshen it up again many years from now with no problems. If you bore it to something like .030 over it may not be able to clean it up again after years of wear. But if it does need to be bored you can go as much as .040 over with no issues and it should last as long as it has before the rebuild.

BigMike80

It would be a basic cruiser but I still want a car with some *****. What would be the best way to go about this? Big Block? Also are there any advantages to a small block over a big block other than the weight? Thanks for all the info so far I really appreciate it.

Also does anyone know any good books to get on the subject of muscle car engines and restoring mustangs?

mustanglover66

I have heard good things about a book called rebuilding your small block ford. To get more ***** out of it think heads, cam, intake and carb. boring it does't do much at all for power.

toolwench

Small blocks usually get better gas mileage. Also, if your car wasn't originally a big block car, there's a lot of necessary mods to make it one. When I first started, I had a 289 and as I learned more about engines, I used it as a guinea pig to try things. From 2bbl to 4, different intake, manifold to headers, different cam...some of these I changed out quite often because they're relatively cheap and easy to do.

Now, I've got a mild 302 and a crazy 347. The 302 puts out around 250hp (nearly the slowest in my collection), the 347 around 400hp (3rd fastest in my collection). And no matter which route you go, sometimes it's the tuning that makes the real difference anyway. You can't just drop in a big motor without matching the rest of the drivetrain, traction and brakes to it, either.

javier146

I have a 351w and i like it, I used to havea 302 in the stang and it was way to slow for my blood, once I get a sum of money again I will go for stroking the 351 to a 408. This of course will probably make it a horrible daily driver.

67mustang302

You can get a small block to have ***** too. It depends on how much you want to spend and how much power you want to get. But small blocks get better mileage for sure, they also rev up more quickly(generally speaking) but cost FAR less. Most big blocks can be quite expensive to build if you need a bunch of stuff for them. Big blocks can be a real pain as far as sticking them in some cars, and they get crappy mileage. The reality is you can get any small block to put out more power than you could ever possibly use on the street, provided you're willing to spend the time, effort and money to do so, and you still have the economy of small displacement.