is this true about a 350 sbc vs a sbm

[nothingface5384]

Its not a crap argument.I will let Smoky explain it. Read and learn.Smokey yunick was perhaps the greatest exponent of long rods and he was the one who made the categorical statement " run the longest rod you can stick in the motor"
Smokey explained that w/ a 5.7 rod the piston would be within .001 inch from tdc for 5-6 degrees (on a 3.48 stroke) going up too 6 inches on the rod the piston would "dwell" within .001 thou for 10-12 degrees . This slow turnaround makes life easier on the rod on the deadstroke when tensile strains can break rods.
So i,m thinking a long rod motor will last longer.

yes I know about this, I just ment no one really builds an engine to a magic bore to stroke ratio, nor is there a universal onw otherwise every engine would be built with w/e the ratio is

just about every engine is within the 1.5 to 1.7 range regarding bore/stroke ratio

my buick 350 has a stock bore/stroke ratio of 1.65
stroke it to a 373 with same length rod (6.380)and i'm only down to 1.6..nothing to make it preform worse nor piston slap
bore stroke ratio isnt really important when building an engine
but yeah if youre able to stuff a longer rod combo in there then go ahead

 

[daredevil]

My point was a mopar sb will outlive a chevy sb due to less rod stress with the longer dwell time. Answering the original question.

 

[teringer]

having owned ford ,chevy and mopar stock cars, all were small blocks the main difference between them all is mopars were the fastest but required a lot of extra block ($) advantage 18deg head, chevy's, with there 4 bolt blocks, main bearing having there own oil galley, and 5 head bolts, you can run higher compression and both mopar and chevy have good flowing stock heads, there nothing you can say good about the 351w engine ,poor stock heads, bottom end to heavy .we won 6 champions ,took 2nd 7 times and 2 times finished8/9 in 15 years of racing .we one all the championships with the chevy's, mopar took home 5 seconds, ford 8/9. these were 25 races per year and we used only one motor per year with a well used one as back up. we fielded 30/35 cars per night with only 22 making the grade. so for hp the mopar won ,for higher compression, lighter rotating weight chevy won, the only good thing I could say about the ford is the dist is in the front.just my 2 cents

 

[Dartnut]

having owned ford ,chevy and mopar stock cars, all were small blocks the main difference between them all is mopars were the fastest but required a lot of extra block ($) advantage 18deg head, chevy's, with there 4 bolt blocks, main bearing having there own oil galley, and 5 head bolts, you can run higher compression and both mopar and chevy have good flowing stock heads, there nothing you can say good about the 351w engine ,poor stock heads, bottom end to heavy .we won 6 champions ,took 2nd 7 times and 2 times finished8/9 in 15 years of racing .we one all the championships with the chevy's, mopar took home 5 seconds, ford 8/9. these were 25 races per year and we used only one motor per year with a well used one as back up. we fielded 30/35 cars per night with only 22 making the grade. so for hp the mopar won ,for higher compression, lighter rotating weight chevy won, the only good thing I could say about the ford is the dist is in the front.just my 2 cents

This post speaks volumes on real world results, not theories.

 

[66fs]

In the real world, daily driver on the street, sbm was better in HP and durability than a sbc, until the 80's, when I stopped rebuilding engines. As far as I was concerned high performance was nearly nonexistent past the mid 70's. The sbm did not need 4 bolt mains, nor did it have oiling problems. Ask anyone with a 340 and a 3 or 4 speed. As for compression, we were all limited by pump and unleaded gas soon enough. The sbc did not have a good intake or exhaust manifolds. Chevrolet had an uncanny habit of snatching defeat from the jaws of victory by being too cheap. 4 bolts to try and seal flimsy valve covers, cheap timing sets that were all but shot after 50,000 miles, small diameter lifters that failed and chewed up cams, 11/16 valve stems with no stem seals, small diameter valve springs that lost rate all too quickly, and a filter bypass that could recirculate debris throughout the engine, and the cheapest hardware available. Who else used shims to correctly locate their starters, because of poor machine tolerances??? In racing you can throw all that away and use only the good stuff, bringing sbc and sbm closer in performance. I rebuilt enough sbc in my day and they always showed more wear that a similar sbm and always had hardware break, unlike Mopar and Ford. In stock form, daily driver, there is no contest. The sbc is the least factored motor in NHRA and NASCAR. It is the least competitive and least durable. How many times was the 340 factored to higher HP to make the sbc competitive? How many times did NHRA defactor sbc to a lower hp because they over estimated hp numbers? How many times were Ford and Chrysler punished by adding weight or changing body lines to make Chevrolet more competitive? You can't have it both ways, crying that the other guy is too fast and then claim you are the best. Give me a break!