wadda ya think

[megaladon6]

dished pistons create a tight quench area. this prevents pre-detonation. you don't have to do this when using a blower but the higher the static compression and the higher the boost the more it helps. i wouldn't use cast pistons with a blower anyway. they won't take the abuse. hypereutectic pistons can take the higher compression, seal better, are lighter, and stay cooler than cast.

 

[Silent viewer]

is he going to even be able to get even close to good compression running dished pistons though??

 

[megaladon6]

took a quick look through kb pistons--chevy 350 hyper 12cc d-dish piston with 64cc heads=9.6 compression. not bad, allows for pump gas, decent timing. to go higher you could deck the heads. but since the d-dished piston squeezes the gasses into a very small area around the plug it ensures a faster burn and more power because the air/fuel mix is better and the flame front doesn't have to waste time and energy spreading out.

 

[Silent viewer]

interesting......

 

[megaladon6]

heres a good article on cylinder dynamics.


http://www.popularhotrodding.com/tech/0606phr_understanding_compression_ratio/

 

[83cut350chev]

took a quick look through kb pistons--chevy 350 hyper 12cc d-dish piston with 64cc heads=9.6 compression. not bad, allows for pump gas, decent timing. to go higher you could deck the heads. but since the d-dished piston squeezes the gasses into a very small area around the plug it ensures a faster burn and more power because the air/fuel mix is better and the flame front doesn't have to waste time and energy spreading out.

so 64cc chambers would be a good idea? what size cam do u think would work best with that

 

[megaladon6]

seeing as i don't know how far you're willing to go, here are some general recommendations to get you 400hp. convert to a 383ci. this will also allow you to raise your compression some. i would use vortec 64cc heads either way.
for a cam you should go to a few manufacturers web sites and ask them. i am not a cam expert. i read up alot on the physics of cams and asked around before i made my choice. just remember that (this applies to carbs too) bigger is not always better. staying with a 350ci---unless you want to build a top end only engine stay within .500 lift and 240deg duration at .050 . i would use a roller cam. if your block is not originally a roller block and you can't afford the conversion lifters, i'd use a compcams xe series cam. they have extremely fast ramps and perform like rollers. the xe268 and 262 cams should be good. if you go with a 383 you can go larger. my cam (xe274) is a bit large for a 350 but would work. in my 383 it has a smooth idle, high vacuum, and power through 5k. actually i wish i went 1 size larger.

 

[85 Cutlass Brougham]

Well, you say you wish to have 400hp, but what characteristics does the engine need to have? 400hp from a 350 can be done a number of ways and the parts you need differ by what you wish the final engine to do. Is a smooth idle desirable or do you prefer a rough idle? Does fuel economy matter to you? What fuel do you wish to use-87? 93? If you want a streetable combination, I would suggest the XE268 cam from Comp Cams or the GMPP Hot cam, 10:1 compression-using 4 eyebrow flat top pistons and the proper chamber size instead of popup pistons, a set of the Patriot heads ( low buck) or a good set of 170-185cc heads from another manufacturer, Edelbrock Performer RPM intake, a properly set up Quadrajet and a MSD HEI distributor. This should be a good idling street engine with tons of torque. It will possibly lope but be useable. You do not need a stroker engine to reach 400hp, but it would have better torque and idle smoother as compared to a 355 given the same components and specifications in each engine.

 

[83cut350chev]

Well, you say you wish to have 400hp, but what characteristics does the engine need to have? 400hp from a 350 can be done a number of ways and the parts you need differ by what you wish the final engine to do. Is a smooth idle desirable or do you prefer a rough idle? Does fuel economy matter to you? What fuel do you wish to use-87? 93? If you want a streetable combination, I would suggest the XE268 cam from Comp Cams or the GMPP Hot cam, 10:1 compression-using 4 eyebrow flat top pistons and the proper chamber size instead of popup pistons, a set of the Patriot heads ( low buck) or a good set of 170-185cc heads from another manufacturer, Edelbrock Performer RPM intake, a properly set up Quadrajet and a MSD HEI distributor. This should be a good idling street engine with tons of torque. It will possibly lope but be useable. You do not need a stroker engine to reach 400hp, but it would have better torque and idle smoother as compared to a 355 given the same components and specifications in each engine.

idle smooth or rough doesnt really matter to me, im already at about 10-12mpg anyway so that doesnt really matter either,i would still like to uses 87 octane. i will look into the new pistons u were saying,as wells as the others

thanks

 

[megaladon6]

i just remembered something about hypereutectic pistons, especially KB and Silvolite. they have a much tighter fit in the bore so the block will need a machine shop to set it up right. you'll probably want to bore the cylinders anyway, depending on how old the block is.