Building mine now, forged Eagle crank and rods, JE domed nitrous pistons. Should be able to handle 7500rpm and still be reliable. And cost is still somewhat in check at right around the $4k mark.

 

Few things....

1. Assembly and checking clearances/tolerances goes a long way to making things live. The problem is on "Chinese" stuff that the parts usually need more tweaking to work. Then again the best pistons I've ever used are imported, but thats from across the other ocean, not the pacific.

2. Mass and piston speed are two things that need to be thought about for long term durability. You can run a weaker crank and block with lighter parts and less piston speed. If you put more stroke or more RPM in a motor it beats up on cranks and blocks, so you need stronger cranks, lighter parts and better block prep (4 bolt etc..)

3. Good Chinese parts = Eagle, Scat. If the pin bores are tight on the rods, they need to be fixed. You need to measure and set bearing clearances on the rods and mains and use different size bearings to get them right if need be. There are varied reasons to use and not use them, but most times they are on the more affordable side of the scale.

4. Good American parts = Crower, Manley, Lunati, Callies, Howards. There are a lot more but that's the more budget orinented stuff. These guys make some good cranks and rods, same assembly procedures apply.

5. Pistons = Diamond, Mahle would be my top two favorites. JE/SRP is on my **** list, Weisco, Ross, CP, BME, Lunati, Manley, Probe are not something I use commonly but they are all good as well. I know Weisco and Diamond are in Pro Stock motors with the Professor and KB Racing (Anderson/Line), Mahle is a big time NASCAR and Sports Car racing supplier.

Bret

 

Speaking of clearances, I have a crank that has been cut .010/.010". What is there to do if I can't get my clearances where I need them? Unlike the standard crank where you can get +/- bearings.

 

I've been to 7000 plenty of times on a cast SCAT crank, SCAT Pro Series I-beams (6.125) and Cosworth pistons. Its still a two bolt block, and its taken the abuse of a 250 shot many times.

Jason

 

i turn mine 7k regularly with 4340 eagle crank, h-beam rods and forged srp pistons runs like a top. As said before though the clearances really need to be watched some of my wrist pin bores were too tight and needed to be honed.

Scott

 

That's one of the reasons I don't like undersize stuff unless you measure your main journals with the bearings in them and grind the crank accordingly.

Bret

 

So who makes a better opti??
AL

 

True...makes sense.