I'm running some mild L35's with 2.02 x 1.60 Ferrea Valves. My nest engine with have either Vortec's or more effort L35's. Flowing heads as we speak!
If I was building a MAX effort 4.3 to run 9's I'd get a BOWTIE block. I'd run NO shaft.
That being said, I have little issue with the balance shaft engine for daily use up to ~600 hp. Being that a turbocharged engine is kind to a shortblock under cruise and off the pedal conditions it's not THAT big of a deal if we think the block is weaker here or there.
Now, I DO have Billet Main Caps, a FULL LINE bore and PRECISION balancing on an $80,000 balancing machine in my shortblock. It is VERY smooth up to the 5,800 shift points and combined with the Ported L35's that came on the engine makes for an alltogether different running engine that the a stock SYTY drivetrain. The L2441's are VERY noisy at .0045 piston to wall for about the 1st 20 minutes of driving, but other than this it might as well be a stocker!
A few Kettering, (GMI) engineers and I were bench racing the other night and the topic of RIP THE BALANCE SHAFT OUT came up. My 3800 customers on ClubGp do this in the 10 and 11 second cars. The shaft does INDEED work at all speeds and keeps some nasty 1st, 2nd and 3rd order harmonics at bay. Being that the 3.8 Grand Nationals and the Stock 4.3 V6's were designed to rev to about 5,200 MAX in NON balance shaft configuration we can partially see why GM went to the expense of installing a balance shaft in the 4.3 V6's and the 88 and newer 3800 engines. The balance shaft DOES work even after idle. Mercedes Benz and the REST of the world uses them as well. This isn't JUST ANOTHER GM band aid! Although it's easy to think that!
90& of the reason for a balance shaft is customer perception and satisfaction especially at idle and that last 10% may indeed help engine longevity at higher RPM's.
BOWTIE blocks are NON balance shaft. For ALL OUT racing no one is going to use a shaft!
But most of the SYTY builds I see are in fact street trucks. If I had a FREE 4.3 L35 I'd use it for sure! I would certainly use BILLET MAIN CAPS, EAGLE or OLIVER RODS, FORGED PISTONS, and PROBABLY one of Mike's Billet cranks.
True this seems like overkill on the street especially for a supposedly weaker block but I encourage anyone in the DETROIT area to come by for a quick ride.
