I seen a set of Le3 Lt4 heads, have the 2.08/1.62 valves.. I had the crank polished, rods reconditioned, balanced and speed pro forged pistons flat top w/ 4 relief valves.. Will these heads fit alright as far as valve to piston clearance? And will my bottom end handle a 6800? I currently have the 306 cam and run 6500.. Any info would be greatly appreciated..

 

not sure on the pistons but the stock rods may not be too happy with the le3 setup. The scat I-beams are pretty cheap insurance, under 300 i think. Or maybe even step up to a h-beam design, still under 400 bucks i would say.

 

Alright, I wanted to avoid tearing it back apart if possible, could I do my 306 cam and just run them to 6500 and still get good results?

 

Not really sure there, i'm turning my cc306 to 7k on the stock lower end, i'm not expecting it to last forever though, hahaha. I think you would prolly be ok for a while i guess, maybe do a search for the limits of stock rods, i think around the 400 rwhp mark and a lot of rpms they are close to what they can stand up to.

 

alright, i just want it to last from this spring till next winter, then im gonna build a 383.. I also run nitrous.. So I dont want it to gernade.. I was more worried about buying the heads and have the valves hit..

 

Not sure if the 2.08 intake valves will clear the small valve notches in the "4 eye brow" pistons. Probably depends on the cam used, etc.

A piston with larger intake valve notch will work fine but not sure with those pistons.

 

alright, Im using the cc306 cam.. does that change anything.. The motor has very low miles on it, Id hate to tear it all apart and replace everything already..

 

the stock rods are rated at 450hp. Many guys with blower setups run them, guys spin the bottom end to 6800rpms. But if your building a street motor you want to build it stronger than what you will need. Unless you plan to take it apart in the winter and inspect the parts. For 300-450 you can get a few different forged rods, do it once and be done with it. You would be real angry if you throw a rod once the motors done. I don't really know about the clearence issues, sorry can't help you there. good luck

 

as far as the valve-piston clearance goes i almost wonder if a calculator exists where you enter all of the information, haha. I guess the only way i can think of is to fully assemble everything and put some grease or something on the piston to see how far the valve smashes it down when you turn it over by hand, If the valve hits i'm not really sure if you could tell though, lol

 

Somarao, you mentioned 450 hp... is that Bhp or Rwhp?

One way to check for piston to valve clearance is with putty. Put a few pieces on the valve reliefs on the pistons and turn the engine over a few times by hand (you only need one head on with a crushed head gasket). Remove the head and measure the thickness.

You'll want some clearance for heat expansion as well as high RPM use.

 

I went through this problem with my buildup. I wasnt getting enough piston to valve clearance and had to go with a thicker head gasket to get the clearance which killed quench in the end.

My advice to you is to invest in a nice set of mahle pistons with the correct reliefs and probably a set of those scat rods with the good hardware. Better to do it right the first time. You will not regret the extra money spent.

Steve