Mach 5's TGP 3.1 big numbers build

[Xnke]

I don't think they are. They are offset beams anyway-would be too much work to make them fit. Grind the crank to BBC size and get some BBC 5.7" rods, bush the pins down, and it'll break just the same, be it a stock cast, forged steel, or crower billet.

[Guest]

eagle makes an H beam with a 2.25 big end designed for a floating pin. You could have pistons made for a floating pin instead of press. designed for 750 hp. only $430 from summit

Crower makes an I beam that I know of so maybe they make an H beam for the 4.3 as well. a phone call or website might have details.

You can get the 4.3 rod in a 5.7 in length as well as 6.0 I think.

some specs listed here on the eagle rods. gonna have to know the specs on the factory lx9 rods to know if they will work with the lx9 crank. http://www.importpartspro.com/crs570063d.html

[Mach 5]

crank with the larger 2.250" rod journal wont clear 3.1 gen 2 lg5 blocks. but this info is definitely interesting at one point I was considering using a larger rod to increase dwell but at the other hand I was thinking detonation may be an issue.. although prob not..

[Guest]

I can't fathom why you want to limit yourself to the gen2 block. You're being counterproductive to your end goal. A larger pin crank will be able to hold up to the power and torque you want to produce much more easily than the smaller crank pins required by the gen2 block. Also the oiling is vastly improved in Gen3 blocks along with even more strengthening through the intake valley, cross bolted mains that I suspect will be an issue at the power levels you want to achieve.

The only "gain" you get with the smaller pin crank is a lower bearing surface speed, which with the newer lubricants and bearing materials is less of an issue than it used to be years ago.

[Mach 5]

I will be modifying the oiling system in the gen 2 block. 2inch journals will be ok as long as the crank is made with 4340 with hollow journals.. A common trend with sbc used to be turning down journals to 1.88" for the exact reasoning you provided to reduce bearing loss and weight.

I have my reasons for using a gen 2 block. I will be increasing its strength in many ways along with the ProGram billet main caps which will help towards main cap flex.

[Xnke]

You are having problems with crank breakages....so you are removing material from the crank in the area which it commonly breaks...

Best of luck buddy, you've got your work cut out for you.

[Mach 5]

well I was wrong.. the crank didn't break this time. I just guess since I was frustrated. realized something else was going on when I started pulling it apart and found coolant in my header. This time I broke a valve head off on cyl #5. I gotta continue tearing it done. we believe the valve broke due to a combination of my short runner header for that cyl and excessively worn valve guides for the exhaust.