[Master Sergeant]

Have to rebuild the BBC 489. Am thinking of going to a Dart block to get the extra CIs. If I order the block from a place like Jegs or Summit how much machine work/money will be required before it is ready to be assembled? Will it make a lot of difference in HP/reliability? Money is tight

 

[Wannabe]

You were right with the increased cubic inches. That is your horsepower advantage of the new block. Reliability will be increased, but they do not come all that perfect. And I would get it from Dyno-flo rather than Jegs. You will save about 200 bones right there.
But make sure you check everything before assembly. Don't assume that just because they are cool, that they come right from the factory.

 

[David 519]

Have to rebuild the BBC 489. Am thinking of going to a Dart block to get the extra CIs. If I order the block from a place like Jegs or Summit how much machine work/money will be required before it is ready to be assembled? Will it make a lot of difference in HP/reliability? Money is tight

Plan on bore/hone to size, hone lifter bores (usually tight), check align bore (usually good on Darts), check deck (had to deck the last one I did, not square). Budget a grand for machine work, you should (might) have $$ left over..... or not.
Oh and +1 what wannabe said about buying the block from Dyno-Flo... just don't let them do the machining for you.

 

[Widetrack]

X2! You might check with Chris Sturab on the forums he made me a good price and they have a 250.00 rebate going on now too! And Yes there is still work to do to the block! Bore mains lifter bores decks etc. all has tight or high tolerances! WTdevil

 

[CNC BLOCKS]

This is what we do to finish machine a Dart Big-M block

Some block notes:
I deck all of them to a finished number depending on gasket & desired piston height

Block needs to be honed with a plate or bored & honed depending on bore

Bottoms of bores need to be chamfered

Most need the lifter bores honed, at the least checked

Most need line honing

All pipe threads need to be retapped

Oil return from fuel pump cavity needs to be done

Core plug holes need deburiing

CHECK THAT THE DISTRIBUTOR GEAR DOES NOT CONTACT THE BLOCK BY THE CAM. There is a big cast blob down there you may want to relieve.
You can machine the gear to clear if you forget but it is nicer to fix the block if necessary.

Check all the timing bolt holes with air, some may go into water. Same with the motor mount bolts.

We also deburr around the rear main bearing area and also deburr the main housing bores as well.

Lifters should be present when checking lifter bore clearance as we have seen quite a few sets of lifters that have been under size and with a stock GM bore the oil clearance would have been at .003 to .0032

Dart has lowered their price on the Big-M blocks by 250.00 and there is no longer any rebate offer on those blocks.

 

[aquacraft]

Well worth the money to do it right.

 

[3V Performance]

This is what we do to finish machine a Dart Big-M block

Some block notes:
I deck all of them to a finished number depending on gasket & desired piston height

Block needs to be honed with a plate or bored & honed depending on bore

Bottoms of bores need to be chamfered

Most need the lifter bores honed, at the least checked

Most need line honing

All pipe threads need to be retapped

Oil return from fuel pump cavity needs to be done

Core plug holes need deburiing

CHECK THAT THE DISTRIBUTOR GEAR DOES NOT CONTACT THE BLOCK BY THE CAM. There is a big cast blob down there you may want to relieve.
You can machine the gear to clear if you forget but it is nicer to fix the block if necessary.

Check all the timing bolt holes with air, some may go into water. Same with the motor mount bolts.

We also deburr around the rear main bearing area and also deburr the main housing bores as well.

Lifters should be present when checking lifter bore clearance as we have seen quite a few sets of lifters that have been under size and with a stock GM bore the oil clearance would have been at .003 to .0032

Dart has lowered their price on the Big-M blocks by 250.00 and there is no longer any rebate offer on those blocks.

I have got quite a few Big M and Little M CNC blocks from Carl. Very good machine work and at a great price. Last Big M sportsman block was just $2345.00 all machined and ready.

 

[wirsboguy]

big m

Try ATECO Engines in IL. Bill is a master wholesale distributor, and gets some good deals on them. He will do all the machining in house and ship it to you. Call him at 847-623-2737.

Good luck.

 

[g935]

Oh and +1 what wannabe said about buying the block from Dyno-Flo... just don't let them do the machining for you.[/QUOTE]

Dyno Flo?
I learned a hard lesson trying to save money with them. I figured about a 10K lesson. The machine work and the clearances were all wrong. It's pretty sad when they give you a piece of paper with your motor that tells you to have a professional check all clearances before you run the motor because they are not responsible once the motor leaves their shop.
Geoff

 

[CNC BLOCKS]

Oh and +1 what wannabe said about buying the block from Dyno-Flo... just don't let them do the machining for you.

Dyno Flo?
I learned a hard lesson trying to save money with them. I figured about a 10K lesson. The machine work and the clearances were all wrong. It's pretty sad when they give you a piece of paper with your motor that tells you to have a professional check all clearances before you run the motor because they are not responsible once the motor leaves their shop.
Geoff[/QUOTE]


What was wrong with the machine work????

 

[gn7]

Dyno Flo?
I learned a hard lesson trying to save money with them. I figured about a 10K lesson. The machine work and the clearances were all wrong. It's pretty sad when they give you a piece of paper with your motor that tells you to have a professional check all clearances before you run the motor because they are not responsible once the motor leaves their shop.
Geoff

I read that twice. And still can't see where it says anything about clearences. Maybe thats why they put the paper in there. Just an indication of the customers they have to deal with daily. They can't read instructions.



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[22HotKt]

I bought a Big M 540 short assembled from Scott Shafiroff in Sept. They didn't sell me a one size fits all off the shelf short. They were very knowledgble about open water marine cooling systems and how to clearance the motor for it. I started like you pricing basic materials and found that the assembled short cost less than the parts. I paid $4395 for the short less cam - free shipping and Dart sent me a rebate check for $250. I also bought Dart Pro 1 Heads. Dart says the std BB head bolts are fine. Not true there are 4 head bolts that will bottom out and you will blow a head gasket. 4 bolts need to be changed for shorter or 2 hard washers are needed. The Dart block has 4 internal head bolt studs that go into the valley ( add $100 for the kit). SSRE shipped the motor to DHE in Sacto. They delivered everything promised
http://www.shafiroff.com/shortblocks/540_shortblock.asp