Stupid question but must ask...
10-12-2007, 03:15 PM
#1
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Stupid question but must ask... Been around forever on this site...just out of curiousity I want to ask the following:
After reading zillions of threads about what engine size to go with i.e. 346,370, 383, 402, 408...
I am having a hard time understanding why go up in size when I see people running similiar track times, dynoing similiar etc. when they have modded a 346 compared to a 402.
I understand maybe a H/C 346 might produce less rwhp than a h/c 402 but is it really work it?
I just find it strange that someone with a forged 346-347 with H/C, Nitrous, or FI runs faster with similiar weight than someone running a 402 or 370 or 383?
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After reading zillions of threads about what engine size to go with i.e. 346,370, 383, 402, 408...
I am having a hard time understanding why go up in size when I see people running similiar track times, dynoing similiar etc. when they have modded a 346 compared to a 402.
I understand maybe a H/C 346 might produce less rwhp than a h/c 402 but is it really work it?
I just find it strange that someone with a forged 346-347 with H/C, Nitrous, or FI runs faster with similiar weight than someone running a 402 or 370 or 383?
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10-12-2007, 03:30 PM
#3
in the end, its just a different way of going about it.
ex) a forged 346 with FI can easily see 550-600rwhp, no sweat...a 427 could do the same with the right H/C (maybe not quite as high as 600 hp, i've seen it but its less common. the similarity in ETs is due the greater torque down low, a big cube car will mostly likely pull a small cube FI car off the line simply due to torque advantage). BUT chances are, the 427 will have better street manners and a much fatter torque curve. if the 346 is s/c then it will likely use more fuel than a stroker (assuming the stroker has a high CR) and it probably won't make as much low end torque. a turbo 346 would make plenty of power, still not as much low end (or probably overall) torque - not to mention the motor will be hampered by the "wipsaw" effect of the turbo on the street, which will only worsen as the turbo gets bigger and boost gets higher, and will never see its real potential for throttle response and fuel economy due to the lower compression ratio nessecary for running boost. additionally, boost and nitrous shorten engine life and accelerate part fatiuge significantly compared to a n/a motor.
furthermore, once you forge a 346, it can only - realistically - take you so far, especially on the street. 800rwhp is breathing right down the neck of a streetable 346's power ceiling, but it's not uncommon, as far as FI strokers go, to see 900-1000+rwhp on a moderatly boosted 408 or 427. basically, going bigger leaves you more room to improve and lifts your power limitations which, again realistically speaking, most people will never acheive anyway.
ex) a forged 346 with FI can easily see 550-600rwhp, no sweat...a 427 could do the same with the right H/C (maybe not quite as high as 600 hp, i've seen it but its less common. the similarity in ETs is due the greater torque down low, a big cube car will mostly likely pull a small cube FI car off the line simply due to torque advantage). BUT chances are, the 427 will have better street manners and a much fatter torque curve. if the 346 is s/c then it will likely use more fuel than a stroker (assuming the stroker has a high CR) and it probably won't make as much low end torque. a turbo 346 would make plenty of power, still not as much low end (or probably overall) torque - not to mention the motor will be hampered by the "wipsaw" effect of the turbo on the street, which will only worsen as the turbo gets bigger and boost gets higher, and will never see its real potential for throttle response and fuel economy due to the lower compression ratio nessecary for running boost. additionally, boost and nitrous shorten engine life and accelerate part fatiuge significantly compared to a n/a motor.
furthermore, once you forge a 346, it can only - realistically - take you so far, especially on the street. 800rwhp is breathing right down the neck of a streetable 346's power ceiling, but it's not uncommon, as far as FI strokers go, to see 900-1000+rwhp on a moderatly boosted 408 or 427. basically, going bigger leaves you more room to improve and lifts your power limitations which, again realistically speaking, most people will never acheive anyway.
10-12-2007, 07:52 PM
#4
it all depends on your set up. some people do 408 iron blocks b/c they are stong as **** but then again so are a lot of other blocks.. it all depends on what you want out of the car and personal prefernce. this winter ill be doing a 408 w/ a big turbo set up b/c i like how strong they are and one more thing THERES NO REPLACEMENT FOR DISPLACEMENT!!!! (talking in n/a set ups... forced induction is a different subject)
