Dart 351W Alum block...

[EBarnes]

I have been wanting to build a 351W based 427. The Dart blocks can go easily to 4.125 on the bore (advertise 4.165 max). This allows for a 4.00" stroke and a more comfortable rod angle. Also, the Dart block comes with the slightly smaller 351C main bearing (higher rpm with the different bearing speed vs 351W main).

Finally, I want to keep my ultimate track coupe light, so I would like the aluminum block...

So... I saw this eBay item today... Sold by RoushYates. Am I missing something? Roush selling on eBay...and it is ... $1,800 cheaper than what they are selling on their own web site?!?!

Same number - "Dart 31345235 Aluminum Race Series Engine Block SBF 4.125" Bore, 9.5 Deck"

http://www.ebay.com/itm/Dart-3134523...eabac1&vxp=mtr

http://www.roushyatesparts.com/dart-...t-31345235.htm

It still isn't cheap, so I don't want to make a mistake and get the wrong block! Am I missing something?

[Mike N]

Give them a call and ask. They are a couple of miles from me and the guys there are typically great to deal with. I could store that block for you under the hood of my roadster if you want.

[tirod]

Two items to consider, but it's all about what you want to do. First, light is nice, but it is a premium. The actual weight difference in the final tally is incremental and pretty small, plus, it's reducing weight at the end of the car that is already lighter than the other. Yes, the kit is 49 front, 51 rear, and that is the reason brake bias and choice of calipers is somewhat problematic if you want to get really optimal balance.

The other item is heat. The one issue there not discussed much is that heat can reduce the overall strength of aluminum if a threshold temperature is reached. An engine is quite capable of exceeding when there's a coolant problem with insufficient ability to transfer it out of the block. The net result is what is reported across the internet with overheated aluminum blocks - the threads soften and lose their grip, reducing the capability to hold torque. Overheated blocks tend to keep blowing head gaskets.

They sure look cool, and overheating isn't supposed to happen. It usually doesn't in most new cars for years. My experience has been that iron blocks resist it to a high degree, but no block is immune. I've had to glass seal iron block engines, but they were well over 175k. It certainly won't be a major problem with a new build, albeit some do have the issue when a mismatch in components brings it to a head after first start up.

Certainly not trying to convince you do otherwise, just info that shouldn't be left out unknown. An informed decision is always better than not being told. Having climbed a pretty steep learning curve on my daily driver with a blown motor and then transmission in the last 90 days, the concept of knowing things ahead of time comes to mind. But, that's me.

[EBarnes]

First, Tirod, I agree and appreciate learning from other's experience. It is much less expensive to anticipate and avoid issues, than to learn through your own experience! You and a few others (I find Bob Cowan has similar...tastes?..to me, and all of you have put a lot of thought and time into your work, and your posts.

There are opinions, and there is information. The latter helps me evaluate for MY mission, as well as understand what and why and therefore decisions down the road with interrelated issues.

Mike, I talked to Jimbo there. I ended up buying the eBay item last night and needed to pay with my credit card. When I called them, it turns out they were moving some left-over blocks at cost... and the last one went a month ago. They just hadn't taken down the eBay item (or the RacingJunk item, which I alerted them to).

Once we got through a slight misunderstanding as to when I needed this, he processed a drop ship from Dart for a new block, with a 6 week lead time. Turns out it is now $50 under their cost (he had to adjust the shipping down $50 and add it too the item, so the system would accept it).

Jimbo did this with no pressure from me.

So, I have to say from this initial experience I am impressed with this company! And I feel I got really lucky - the going rate is another $2,000 and too steep for me.

This will be a fun spring...

[CHOTIS BILL]

tirod seems to always enjoy pointing out that the type 65 is weight bias to the rear almost as much as I enjoy pointing out that with wider tires in the rear it should be weight bias to the rear . Running 275/315 F/R you have 53.4% of the total tire contact patch is in the rear. Over several decades of designing, building, and racing Sports Racers I found with wider rear tires 53% - 55% rear weight bias was what I shot for and it always worked very well.

JMO

Good luck on you build.

Bill Lomenick

[skullandbones]

Nice score EBarnes! What other goodies are you going to include in that light block?

Thanks, WEK.

[EBarnes]

Bill, it's all good! I have 315/18 rear and 295/18 front. And, well, I guess tirod is right. But weight is weight, so from a road race standpoint a reduction in front weight will not decrease the lateral acceleration of the rear, nor the overall straight line acceleration or deceleration. I have read a 50/50 weight distribution is actually not optimal also. But in any case, reducing weight is never bad.

The heat point was great. I will take all the knowledge I can!

I should add I am planning an aero package. Heat into the tires and all...

WEK...Haven't figured out the internals or induction. I am still learning! Looking into the canted valve KAASE P-38 heads, but get a lot if positive feedback on Dart or TrickFlow too. Would love the cross ram intake from KAASE, as it is ideal for good clearance and torque... But not worth the $. I don't mind spending some $ for a benifit, but even a full set up with ECU and tune...$9K. Too much!!

Got some reading to do!