If a certain capacity is desired - a big bore is the best way to get it if you want an engine you can lean on hard all day. Despite all the theories out there, reality is the big bore engine will make more power than the long stroke engine of the same size and have increased rpm capability without dropping off power like the stroker ultimately will as pumping losses, piston speed and friction take over. The big bore engine will also make similar torque.
Now that will confuse a lot of people and goes against what the magazines print - sorry about that.
The reason people go for the big strokes is simple - it allows you to make the engine even bigger when the bore size is at its largest safe size.
The mountain motors use huge strokes to get huge engine sizes - and while the math ***** - they make enormous power due to their sheer size and the strength on the parts used to hold it all together.
Would you see a mountain motor last in a 24 hour endurance event - NO FRIGGEN WAY!!!
Can a big stroker last on the street?
YES. Because they seldom see the redline, and when they do - it is for a short moment in time.
If you want to see the inside of a Viper block - build a 550 engine, rpm it to 7000rpm and sit on that over the Silverstate Classic 90 mile race. Chances are you'll have a see through engine not too far from the start line.
But if you keep it under 6000rpm and drive it like most Vipers get driven, and shift at 5500-5800rpm - a well built stroker should last for years and be very reliable in its reduced lifespan. It can't last as long as the stock engine does because the side loadings will wear the bores faster - but we are splitting hairs because the stroker could outlast most ownership cycles. Let's face it, when you start reaching 600+hp you can expect rebuilds/refreshes sooner than the 100,000+ miles a stocker might last.
The problem with the Viper is that as mentioned - boring it out is not an option. It will safely take 0.030" which is too small an increase to justitfy the exercise unless you have worn bores that need it.
Therefore stroking is the ONLY safe way to go big on the Viper.
510 can be very strong if you re-treat the crank after it has been offset. If not re-treated it's limits are likely to be less than the stock crank... but that leaves room for plenty of power - because people have made 1200rwtq+ on a stock crank.
542-550 is possible with custom cranks and builds lots of power, and can be a great street/weekend strip motor if you keep the rpms to a sensible level. If you want 7000rpm however - it can be done - but it ain't going to be a 10 year 50,000 engine.
For naturally aspirated Viper engines - bigger is better up until around 550 cubes. After that (which could be done) piston speed and rod side angles will start reaching extremes, but someone will be sure to try it, and it'll work on a dyno, and possibly at the track.... but it will not be good for long 5th gear roll outs to the fuel cut off.... lol
For a BOOSTED V10 engine - a stroker will increase power at any boost level.... however a stronger engine could be built with a smaller stroke. The smaller engine could be built to hold together at high rpm all day, and the power loss from the size reduction more than overcome by adding more boost. In other words - at the limits - a stock sized or destroked Viper engine will have more power potential than a bigger long stroke engine that will simply not tolerate the boost levels and rpms the smaller engine can take.
In a dyno competition and for 1/4 mile runs - a long stroke engine can pull the numbers, but a square or an oversquare engine makes a better high performance engine as they love to rev and will do it with more dependability.
Somebody making a 1500hp stroker 550 twin turbo will prove nothing - because well over 2000hp can be made from a smaller than stock engine. People are getting over 1500hp out of factory iron block small block Chevy's, even on a hydraulic cam.
A good street engine can tolerate rod/stroke ratios in the mid to high 1.4's - but rpms under 6k are advised if you want any kind of engine life. They are hand grenades under 1.5:1 held together only by the integrity of the parts and the quality of the build. Like I said - it can be done, but it isn't good math.
The best high performance engines that you can lean on with confidence anytime anywhere and that could take high rpm for extended periods - like around 1.75:1 or better rod/stroke ratios.
