BBC block help

Over the weekend I knocked half of me crank out the bottom of the block. I don't have it apart yet but in appears the crank broke at the #2 main. My question is with the mild tune up I run can I still get use a stock GM block?

The motor in the car was a 477 4" stroke Callies crank, GM gen VI block billet caps, filled. 871 28% making 20 pounds with 12:1 static compression. It is a clutch car, 2200 puonds running 7.40's @ 185 with a fairly fat tune up.

I am in the process of building a new car with a TFX but I don't think it will be ready for next season. I have a back up Chevy that I will use for next season in the old car.

Thoughts????

Thanks
Steve Timoszyk
Doran Chevrolet
BB/FC

 

We run a 4 bolt main chevy in the altered its a 468, aluminum rod motor with 13:1 and 671 on top, I ahve spun it 50% over before and had no problems with a pretty lean tune in it, it runs 7.30@190 in the quarter and 4.50 170 in the 1/8, again not many problem on than the usual stuff and parts just getting old and what not. My guess is that it would be okay as long as you are smart with the tune and dont go too lean and pop it. There are a few better opinions on here that I hope will chime in. There is another altered in Kc that is running in the 6.90 @190 and 4.40 @ 175 with a standard chevy with iron rods that doesnt have many issues either.

Sean what is your combo on the metal mafia car???

Hope this helps man.

Bob

 

How much ignition timing?
What heads?
What ignition?
What fuel pump size and orifice sizes?

 

Mid 7's. All day long for years to come. I Like an old crusty tall deck truck block, if you can find one. Fill it to the deck so the holes stay round.
Jeff

 

i run truck block tall deck camaro 2700pound 10.5 to 1 iron head bme rod 20psi 7.75 179 5 year never broke

 

With the price of a good CNC bowtie, or the like, why not just spend a few more dollars and get a solid piece. Then you won't have to fill it and hurt the ring life.

 

Many years ago I used a iron BBC truck block (BB/FC and AA/DA) as a back up to a Rodeck; but with compression closer to what iron468 uses. 1/2 inch head studs help as does filling the block (especially if bored big). 4 inch stroke .090 over bore (472") 40% OD 6-71.

 

Timing @32, Heads are Bowtie water, Mallory SM V, Pump is an Enderle 110. Block is filled.

Thanks for all the reply's. I understand buying an aftermarket block would be the way to go, but I have a back up motor with a GM block already, I will just have to fill it.

Thanks

Steve

 

I would also be interested to know if you have your blower set back any....this would help to distribute horse power more evenly among the cyliners. If you are making all of your power in the front of the motor while the back cylinders are "along for the ride" this will cause stress on the crank.

 

Most of my experience is with motors very similiar to what you're listed, but its been in tractor pulling.

When we were breaking cranks, it was because we were too lean around that 4500 RPM area. It seemed like no big deal since we rarely ran that slow of RPM.

We would fill our blocks to the top of the deck. We would crack the deck starting at one of the stud holes, it would travel into the cylinder wall. We never liked the fact that 1/2" studs made the weak spot weaker, although we tried it, and it cracked also.

Tell us about your fuel system.
Main Pill
Hat Nozzle sizes
Port Nozzle sizes
etc

 

We just went through the same problem back in aug, cracked it right between 4 and 6 then took out the cylinders and then at some point 2 as well.

 

chevy block

Steve i ran the same factory block in my car for ten years, i found that running a billet crank helped reduce cap walk. other than a little cap walk i had good luck with the factory unit.
i'd be interested in seeing what you find when you pull that motor down. seeing those piston rings coming out the pan got me to wondering if maybe the piston pins were the weak link, if they were flexing and broke the piston and then wedged the rod in the bore and possibly that broke the crank?

that's another weak link in the chevy the factory size 990 pins. did you have hemi size pins in that setup? if

 

Scott you may be right on about the pin. They are/were factory size pins. The rod/pin pulled out of the #2 piston.

Thanks for the input.

Steve