New Dart Ford Small Block

Has anyone looked at or used the new Dart Ford small block that is in the May Hot Rod new stuff?? It has siamesed bores, four bolt mains (in 302 or 351 diameters), deck hieghts of 9.5, 9.2, 8.7 and 8.2. Many other nice features. I guess my main question is if the Siamese cylinders are appropriate for street use? Would love to hear pro/cons from you hard core motor builders! - Lynn

Lynn, there's some pretty good tech on this subject in this thread over at Corral.net.



Regards,
Mark

[ May 08, 2002: Message edited by: Mark Worthington ]

Apparently, no one cares, but the June issue of the Hot Rod has an article about this new Dart block. Still wondering if it would be usable in a street car. I especially concerned about the Siamese cylinders and heating/cooling issues.

Here is the spec sheet I received from Dart:

Lynn,

I care.

I think that block would be excellent for a street or race motor. There are lots of pushrod engine designs that use siamese bores with no ill effects. I don't think this one would be any different.

As for four bolt mains, yes, I think they're nice but not necessary. Just speaking from what little I know about building Ford motors I've not had problems with a properly setup bottom end and 500 hp on stock two bolt main block. With lots of boost. With a heavy car (3950 lbs). And drag racing. A lot.

But I do use girdles.

Folks think they need four bolt mains a lot since Chevy has them. Well, good thing. The Chevys need them just to stay together as is.

What is the price on these things?

R

[ May 24, 2002: Message edited by: R. Earp ]

Ron, Honestly I was afraid to ask. I did get the card of a distributor over in Moresville, I believe it is. Definitely, in the Charlotte region. These blocks as the guy there said ar e built to take HP in the thousands. An engine built in the 3 digit HP range ought to be bullet-proof.

Hello, Lynn !

Got any pricing on this blocks ?
curious...

Did they happen to indicate how long until an aluminum version will be available?

Beyond a revised main bearing oiling system (was this a huge issue?), what sort of advantages over Ford Racing products are they citing?

Scott

darn, no true cleveland type block. my loss.

The oiling system is VERY versatile and definitely set up to make dry sump easy. Oil can be fed from stock pump and/or external pump. It can be fed in at front and/or back and from either you can select to feed the top end and/or bottom end. The water jacket has been scalloped to allow the Siamese cylinders to have more contact area and flow well. Head bolts are all 1/2". This block comes with many features that would have to be machined into a Ford block

I did not ask about price and allow was not mentioned.

Well guys, I talked to the distributor in Concord, NC about the Dart SBF blocks. He said not to look for an alloy block soon because most of the racers that Dart services are mandated to using cast iron blocks by the rules they follow. He also said that Roush got the first order and that is why there has been a delay getting them to the public. But, Roush and Yates and others were consulted in the design of these blocks and then Dart went about addressing all the complaints and requests for what these guys wanted in a block. One of the biggies is the amount of bore you can get with these and still have plenty of meat left. To get a block with true enough cylinders to get this much bore, he said you'd have to go through 10-20 blocks. With the way the oiling is set up, you don't have to run 90-100psi; this is going to get you at least 10HP back from your oil pump when you drop back to 40psi. Here is the pricing:
<UL TYPE=SQUARE>8.2" deck w/2.25 crank $1990
9.5" deck w/2.75 crank $1990
8.7" deck w/2.25 crank $2100
9.2" deck w/2.75 crank $2100
9.2" deck w/2.25 crank $2250
[/list]
Shipping on these will run around $80.

If we can get an order of 10+, we can get a break on the prices.

Regards,

I wanted to resurrect this thread because I just got off the phone with Dart machinery and they confirmed that they will offer an aluminum block SBF block in February 2003. Pricing is expected to be comparable to their aluminum Chevy blocks, which go for about $4,000. Obviously, the big attraction is the weight savings at about 90 pounds vs about 205 pounds for their iron block. I think the advantages over the FRPP race blocks are 1) the only machining operation required is honing, and 2) availability.

Mark, this is indeed very cool news! In addition to weight savings, I assume the same versatility of oiling the powerplant will be provided with the aluminum block as it is with Dart's iron block. Another huge advantage of an alloy block is the heat transference. This block aught to be, given an adequated water flow and radiator area, much easier to cool than the iron one. I would think that the oil cooler will be much more affective as well. There is probably less differentiation in this area between the Ford and the Dart aluminum blocks, but given this and the advantages that you site, there will be no doubt which block will have the superior potential. I would guess that Dart will make a boat load of money on this! I really don't see the 4.6L modular motor giving it a lot of competition.

[ December 18, 2002: Message edited by: Lynn Larsen ]

$ 2,000 to save 115 lbs?
Reasonable for race cars I guess.

I'd rather put the money into killer brakes or ported aluminum heads.
But if I win the Lottery...

MikeD

I did not see this thread originally. I am having a Dart cast iron motor built by Keith Craft now (did not know the aluminum was coming out so soon). We will se how it goes. One nice advantage to the Dart block in the bore can be taken up to 4.185" which allows you to add displacement without adding stroke. You can always add stroke also, etc.

<BLOCKQUOTE><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><HR>Originally posted by MikeDD:
$ 2,000 to save 115 lbs?
Reasonable for race cars I guess.

I'd rather put the money into killer brakes or ported aluminum heads.
But if I win the Lottery...

MikeD<HR></BLOCKQUOTE>

Mike, saving 115 pounds in a 2,300 pound car results in a 5% weight reduction. That's significant! That's also equivalent to a 5% improvement in your brakes and a 5% increase in horsepower. That translates to 15 hp for a 300 hp engine. Add to that an increase in power due to running the oil pump at a lower pressure, as Lynn alluded to earlier, and your looking at an equivalent 25 hp increase, which is probably about what you would get from porting a set of decent-flowing heads. Plus you still get better brakes out of the deal!

Lynn,
I'm not so sure about reduced heat load. The aluminum conducts heat better this is true. But this means that more heat will be removed from the combustion gases, which will then have to be removed by the water, and then on to the radiator, etc. This is all heat that would of been converted into work or gone out as elevated exhaust gas temp.

It is for this reason that aluminum heads typically have lower knock sensitivity than iron. They remove more heat from the combustion chamber. Ideally, you wouldn't want to remove any heat, but then the block would have to be ceramic (it's been done) to survive the temps.

The aluminum block would reject more heat to it's immediate surroundings (engine compartment), but this isn't necessarily desireable.

Adam

Hmmm... I once heard a road racer say "a pound is a pound is a tenth of a tenth of a second." i.e., 1 lb weight reduction = 1/100th second reduction in lap time. Thus, a 100 pound weight reduction shaves a second off your lap times, and that's HUGE.

I used to have a rule of thumb for my Eagle Talon that said 1 extra HP cost about $25. Of course, you hit a certain point and the cost starts increasing (exponentially, probably), but that's for the "easy" HP gains. BY that rule, 15 (effective) HP should cost about $375, but I think when we start talking about effective HP gains the rule breaks down...

And then there's the factor that the 115 pounds is based on a Dart iron block. A bare Ford 289 block weighs something like 125 pounds, not 205...

Maybe in drag racing, but I would imagine most on here are road race enthusiasts where weight not only makes a difference in acceleration but handling. That is true of not only the weight, but it's location in the vehicle.

David

<BLOCKQUOTE><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><HR>Originally posted by MikeDD:
Mark

I think I'm going to have to disagree with you on this one. Starting with just basic
iron 302 heads, I'm told an increase of
34-40 hp is normal if you switch to GT40 or
Dart iron heads for around $ 1000.
For $ 2,000 I can buy slightly ported
aluminum heads that will net 60-80 hp if I swap cams or change rocker ratio.
And in the same deal I loose 30-40 lbs over
the iron heads.<HR></BLOCKQUOTE>

Fair enough, Mike, I'll agree with you that if your 302 has iron heads then a simple head swap is way more cost effective in terms of increased horsepower and acceleration. I seem to recall an article where a stock 302 picked up 60 hp with nothing more than an upgrade to AFR 185 heads. But note that I said a 25-hp increase is about what you'd get by porting a decent flowing set of heads. In other words, if your engine already has good aftermarket heads, you'll be hard-pressed to pick up more than 25 hp simply by porting them.

[ December 19, 2002: Message edited by: Mark Worthington ]