I have a chevy 400 block and crank with a set of 64cc vortec heads. im in the process of beginning my build. I am shooting for 450hp to 500hp. I would like to run it on high grade pump gas and i need to know the best pistons for this application.
A street 400SBC that runs on 92 octane pump gas needs a dished piston when using a 64cc cylinder head.mlmcmahan42 said:I have a chevy 400 block and crank with a set of 64cc vortec heads. im in the process of beginning my build. I am shooting for 450hp to 500hp. I would like to run it on high grade pump gas and i need to know the best pistons for this application.
Although you are correct about picking up HP by a little port work. You still have small valves and small runners. These heads work very well to 5000RPM and maybe a bit further with the right combination. But I think it's hard to get 450-500HP when restricted to about 5000RPM. Put on a better set of heads and a cam to match and I think the 400 will do what you want. You better have a good bottom end also.ap72 said:If you spend about an hour on each port cleaning it up those Vortecs can get you to your goal pretty easily. You can pick up 30hp just by doing a good job cleaning up your castings.
Hey Ap,you told Dencouch he couldn't make that kinda HP with vortecs on his engine build. What gives?ap72 said:If you spend about an hour on each port cleaning it up those Vortecs can get you to your goal pretty easily. You can pick up 30hp just by doing a good job cleaning up your castings.
if you're looking for max hp I'd just run the 6" rods.454C10 said:here is the first impersonator part.
you will need to use 5.7 inch rods, as the piston selection is much larger with longer rods.
http://www.chevyhiperformance.com/techarticles/148_0306_chevrolet_406_big_block_torque/index.html
My apologies. :drunk: I re-read all 7 pages of the original post,lol.Memories not what it used to be.ap72 said:I said he was limited to about 475 hp as cast. With an additional 30 hp from port work that's over 500.
Its perfectly fine, I'm still relatively young and my memory ain't what it used to be.TroyBoy said:My apologies. :drunk: I re-read all 7 pages of the original post,lol.Memories not what it used to be.![]()
longer rods are much to do about nothing.ap72 said:if you're looking for max hp I'd just run the 6" rods.
Not true.mlmcmahan42 said:Is it true the 400SBC was always a two bolt main? I was told they never made a four bolt block and the conversion kits offered today actually weaken the block?
ap72 said:That, and on enignes where you have a relatively small runner volume (say 180cc's for ported 062 Vortecs) on a larger displacement (400ci) the longer rods will produce more power.
True, the difference will only be about 3-5% but on a 500hp engine that's around 20hp.
Joe Sherman tells me he sees a 30hp gain on a 383 by going to longer rods every time. "Everytime" Is a pretty convincing argument. Also, if you just plot it out short rods for low end and long rods for top end makes sense, circle track guys have known that for years.
Did you actaully read that? There was no argument made that I could see, just that they felt it didn't matter. Njo solid reasoning, just taht there are differen lengths and they all connect a piston to a crank... Duh!454C10 said:
ap72 said:Did you actaully read that? There was no argument made that I could see, just that they felt it didn't matter. Njo solid reasoning, just taht there are differen lengths and they all connect a piston to a crank... Duh!
Plot the piston acceleration rates against the cam timing, and contemplate how a larger runner may affect the airflow in relation to the piston acceleration rates. Keep in mind what you're shooting for in relation to your maximum air velocity and when it might peak.
Its really not that hard to see if you just plot it all out.
ap, you knew dam good and well what this post would result in. Are you taking on the mantle of a flamer now? :mwink:ap72 said:if you're looking for max hp I'd just run the 6" rods.
They did make both styles 2 and 4. From what i have read the 4 bolt version is weaker due to the 400 having larger main journals which makes the bolts closer to the pan rails. Splayed caps is always stronger than the conventional 4 bolt but you need to machine for the caps and then do a line bore which always costs $$$$$.mlmcmahan42 said:Thanks for all the help guys. I really appreciate it. I have two more questions. Is it true the 400SBC was always a two bolt main? I was told they never made a four bolt block and the conversion kits offered today actually weaken the block? And also how extreme of a cam would be best? Im wanting it to be a bad street car and mild drag car.