Destroking an Engine

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The slant guys say their same head on different blocks could produce the same HP, but at different RPM's, 170 would have to scream to produce the power of a loafing 225. Guess it depends on what you want it for. Class racing or oval track. The 273 was always touted as a fast revving small block but the 318 is the same motor with a larger bore, 340 as well.
 
Just to answer the question, the SCCA Trans-Am class displacement limit was 5.0 liter, which is roughly 305cid. Concurrently, they ran a small displacement 2.5 liter class, which was populated mostly with Alfa Romeo GTAs and Datsun 510s.
 
426's got Destroked back in the day to a 396 C.I. , just to take power away. There was way to much power in those engines, the tracks just could not hold that much H.P..... No wrinkle walls back in them days..... LOL
 
To the OP - the right package, matched to the right transmission, will be the best in terms of economy. If you look at the modern cars they are all coming with 6,7,8, even 9 speed transmissions. That's to be able to keep the engine in it's most efficient rpm range more fo the time, rather than for a little time during the rpm ranges of 3 gears. As was mentioned - there are advantages to a shorter stroke and shorter rod ratio. Most being friction but burn time and reduced pumping losses also come to mind. The trick about rpm is no matter how big or small the engine, the more "bangs" you have in a minute, the more power will get to the tires. Period. That's why high rpm engines always make big numbrs assuming they are built to live up there.
 
X2 what moper said

Plus I don't see any reasons to stroke or destroke any Chrysler V8 (except the new hemi) they all have great bore to stroke and rod ratio. The main reason to go with a bigger engine is most people want to keep peak power around 5000-7000 rpm on most street engines. Now if you need more power than a 440 can offer and dont want to add power adders I can see stroking it out. At that point I'd rather go with power adders. As with destroking Chrysler engines are short stroke engine anyways unless your looking for a plus 9000 rpm engine or meet some class it's not needed.
 
pishta said:
The slant guys say their same head on different blocks could produce the same HP, but at different RPM's, 170 would have to scream to produce the power of a loafing 225. Guess it depends on what you want it for. Class racing or oval track. The 273 was always touted as a fast revving small block but the 318 is the same motor with a larger bore, 340 as well.
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Right you are. 273's are the same except for the bore size. The smaller (lighter) pistons may have helped the 273's rev higher but the solid lifter cam really helped. tmm
 
toolmanmike said:
Right you are. 273's are the same except for the bore size. The smaller (lighter) pistons may have helped the 273's rev higher but the solid lifter cam really helped. tmm
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I think head flow relative to displacement also help
 
273 said:
I think head flow relative to displacement also help
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My thoughts exactly with both the slant and the 2V Cleveland destroker engine. No idea about any of the others, this slant is my first Mopar powered anything.
 
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