this will be my first LS venture and I want it to be a real screamer. it will be going in something light(2800lbs right now w/o drivetrain) paired w/ a TH400 and 4.56 gears which is the main reason why I want it to rev to ~7500rpm. so help me figure out my plan! so far I'm thinking something along these lines, LSx block bored to 4.125 but I was thinking about sticking w/ a 3.62 stroke? I don't need gobs of torque and this will keep it rev happy correct? I'm planning on using 6.2" c/r's, all ARP hardware, clevite coated bearings, moly rings and every things going to be forged of course. once I get the bottom end figured out and order everything and have the machine work done I'll move on to planning the top end, my wife is fine w/ letting me spend thousands over time but she would flip if I did it all at once critique my plans so far and tell me what you all think and make any suggestions you may have! thanks guys!!

 

I would say, the most important part is developing a cam that will carry the power up as high as you want. With a factoy spec'd stroke, and enough headflow on top, you should be able to spin it as high as you want.

I would probably look into a solid roller if you want to play that high consistently..

 

it will take a few $ but it can be done. something like this warrant killer heads and intake, solid roller cam, jesel valvetrain. build a large bore short stroke motor to keep the piston speed within range and at the same time as much ci as possible

 

I'm definitely going with a solid roller and shaft mounts. I realize the top end plays a major roll in high rpm applications which is another reason I'm not making any plans for it yet because I'm still trying to learn as much as I can about these engines, of course if you guys have any suggestions like what heads might be best suited for me then by all means, I'll talk to the pros when the time comes to tailor a cam for my set up. this is my winter project and I'm in no rush what so ever so theres plenty of time to learn and plan.
so you guys think I could push it higher? whats the highest revving LSx out there? I think I might only go as high as 8k so it will last for some time.. how important is the rod length to stroke ratio at these rpms? I know its nothing major but I'm trying to squeeze every ounce of power out of it where I can with out spending major $$$ for the small gains here and there. I lost my books last move so does anyone have the RL/S equation so I can crunch some numbers?
I was debating about going as big as a 4.185 on the bore but it sounds like thats pushing it a little on the LSx blocks. I beams will work fine for this build right? I want to keep the rotating mass as light as possible with out forking out some serious money but I don't want to skimp on anything either even if it takes a year or more to build this, like I said no rush. any suggestions on a strong lightweight CR and would you go longer than 6.2"? if its possible, still gotta figure out how much PTV clearence I'll have. and lunati is a pretty trusted brand for forged cranks right? what do you guys think about about cryo treating it or mikronite? I'll have it knife edged as well.

 

Sorry, no info here, I just want to learn too.

 

there out there, the quickest 6 speed car turns around 9k+

 

Don't worry about RPM, if you build the motor for power the RPM will take care of itself. I run a 4.125" stroke, wet sump and with the old sheetmetal intake my 421" used to shift at 8400rpm.

 

what intake? a normal plastic isn't gonna work. single plane or fabricated will probably be needed

 

IMO 7500rpm is not that high you should see S.A.M New engine 9600rpm
NOW THAT HIGH Also Joe from SIxSpeedInc did that too.

I've seen a couple of H/C 346ci car revving it to 7200-7400rpm.

is it possible to have PTV problems with built engine????