Which Block???

[Outlaw]

Looks like I'm building a 540 BBC this winter.
I was going to use my gen6 502 block but have decided
to leave it complete. So what block should I go with???
Dart, Merlin, GM???
looking for 800Hp below 6300rpm

[MACHINEHEAD]

The one you get the best deal on. No real preference.

[BrendellaJet]

I've got a merlin 2 that I am happy with that is making the power you are looking for...I know most will say to go with the Dart block, not sure why. I found mine used & never wounded for $1300 ready to go for my 548...That was a few years ago, prices appear to have come down some since then...

[H20MOFO]

I was told the upper limit for a gm block is 1k hp. Is that accurate? (4bolt properly preped)

[Outlaw]

good question... thats what I understood about 1k hp.

[IMPATIENT 1]

i know someone from this board that's runnin a 4bolt gm blocked 468 with twin turbos and nitrous putting out over 1400hp;) the motor hasn't been touched in 3-4yrs from what he told me, he runs the piss outta it too:D of course a 30 over gm block will be stout enough, but i also know alot of other guys who've been runnin tall decks at 100 over for decades without failure and putting out way over 1100hp.

[fc-pilot]

We have used a couple GM bowtie blocks and have beat on them fairly hard. We have never had a problem with any of them. I really like the GM CNC bowtie blocks. I would not flinch at using any of them. For what you are doing though, I would look around for the best deal on an aftermarket block. Any of them could do what you want and it would even be sweeter if you found a GOOD used block for half the cost.
Paul

[WannabeRacing]

I am with Paul on this. For what you are trying to do, any will work just fine. A bowtie, a CNC bowtie, any of the merlins, a merlin pro, or a Dart. Whatever you can get a good deal on. Make sure it is sound and run with it.
On a personal note, I do not understand the aftermarket world loving the Dart. I have done a half a dozen of them and hate each and every one. I want a block that I can swear by, not swear at. So far, the cream of the crop around my place is the Merlin Pro. But pricey.:jawdrop:

[Warp Speed]

I am with Paul on this. For what you are trying to do, any will work just fine. A bowtie, a CNC bowtie, any of the merlins, a merlin pro, or a Dart. Whatever you can get a good deal on. Make sure it is sound and run with it.
On a personal note, I do not understand the aftermarket world loving the Dart. I have done a half a dozen of them and hate each and every one. I want a block that I can swear by, not swear at. So far, the cream of the crop around my place is the Merlin Pro. But pricey.:jawdrop:
What problems do you see with the Dart, and what do you like better about the Merlin pro?
Warp Speed ;)

[cstraub]

Most of my engine builder customers like the Dart better. They say the lifter bore indexing is correct, the machine work is much nicer, the quality is more consistant. One of these customers does nothing but CNC block work.

[WannabeRacing]

Just a few really quick things as I have to head off to an appointment;
#1 Just try and put a starter on the "Correct" side of the block on a Dart. Merlin pro is drilled for either side of the block from the facotry. Dart does not even cast the driver side so you could drill it. The "Powers that be" told me to weld on the block and then drill that. Well, thanks!
#2 Just try to speak with anyone at Dart that would EVER be willing to help you. GOOD LUCK! They will tell you that you are a moron and too stupid to live.
#3 Had an oil passage messed up on one. Did they help? That would be a big NO!
#4 No recessed areas to put oil gallery plugs, so get the machines fired up and start recessing them yourself. Merlins are right from the factory.
#5 Re tap every thread in the entire block. We do anyway, but with the Dart, you HAVE to.
#6 I have yet to get a block that did not need to be decked, line honed, cam tunnel checked, etc. My last block had the rear main 3 though out of round. That is more than a little line hone. It actually needed re-sized on the rear main. I hate re-sizing a brand new block.
#7 A few of the above don't really bother me, because I check and machine them anyway. But when they tell you that it is CNC'd to perfection and ready to assemble, and then it comes three thou off, it upsets me.
#8 Not really a bad thing, but make sure you hit every one of the freeze plug holes with either a machine or a sanding head. They are rough, and tend to leak if you don't.
They just take a ton of time and money to get right. Once they are right, they are a great block. (Except for the starter deal.) You aught to see what we have to create and fabricate to get the starter on the driver side.
Sorry Chris, I don't know about the lifter holes, I either go .904 or keyway, so the holes are gone by the time it is ready to use.

[MACHINEHEAD]

I love #2. Totally the truth. The Kid on the other end told me that " When you start building enough engines, you will begin to see, that you need to learn to do alot of work, before you can just put it together". This is totally true, but I dont want to hear it from Dart Boy. And Im only 34. BTW the engine (alum. dart 427 afr head) in question is on the cover of Engine Masters, avail. at news stands now! Nice piece after a lot of work though

[fc-pilot]

Because of #2 I will try to avoid using Dart products if at all possible. I received a set of Pro 1 heads that had the rocker studs improperly machined. The problem did not reveal itself until we tried putting rockers on. The tip would fall off the tip of the valve all the way onto the retainer. After trying every possible pushrod length we realized what the problem was. At that time we contacted Dart about the issue (because we purchased the heads strait from Dart). The Monkey on the phone told us "the rocker was SUPOSED to come off the tip of the valve". After a comment was made regarding their prostock motors the IDIOT had the gall to reply that "that is exactly what the prostock motors do too, so just run them".
Paul

[WannabeRacing]

Oh man. I remember that conversation. And just hearing about it again, I am almost in stitches.
Dart has the best customer service EVER!

[cstraub]

Oh man. I remember that conversation. And just hearing about it again, I am almost in stitches.
Dart has the best customer service EVER!
Oh I have had some doozies over the years on getting answers from some. . . it makes this job so much fun.

[Outlaw]

What about World products, merlinIII? any good or bad comments
about them?

[fc-pilot]

What about World products, merlinIII? any good or bad comments
about them?
I can't say. I have not used a Merlin III yet. Every one of these blocks needs to be checked, so from that standpoint it all boils down to preference. I find that used blocks from a reputable builder are great deals because they already worked out the bugs on the initial build so you don't have to have as much work done on them.:D
Paul

[WannabeRacing]

Oh stop! Just because you have a contact that can get Merlin Pros all day long for a fraction of the cost, already with bronze bores, and the like, doesn't mean that we all have contacts like that.
Have not tried a Merlin III. But love to death the Merlin Pro.

[bumpstik]

MH--didn't we swear off Dart products forever? Didn't every dart piece we got have to "finished"? Remember the water leaky heads on that 406 sbc? Yea, I thought so !

[H20MOFO]

Out of all, merlin, dart,world, ect , which has the most cube potential? Or are they all fairly equal? (raised cam ect).

[MACHINEHEAD]

Bumpstik, I have tried to forget about that. And now, hear you go. I have used a dart 502 block in the past with very good luck. However I purchased it new from Russ @ Bischop and Buell in West Covina. When I got it, it was perfect. The price tag for all the prep and machine work was evidence of what he had to do to make it that way. Everything that I have gotten from them has been half finished, bad, wrong or otherwise farged up. And then there is Dart Boy to top it all off! BTW love the merlin stuff

[MACHINEHEAD]

To anyone in So Cal, Russ has the best Machine shop that I have ever come across. We speak the same Language. And EVERYTHING has always been within MY specks and on time, every time for the last 17 years! Damn he's the chit!