questions about big cube small blocks
Thread Starter
Burning Brakes
Joined: Jul 2002
Posts: 1,136
Likes: 100
From: Nova Scotia
questions about big cube small blocks
tossing around the idea of a 406-434 SBC, and have some questions. Im planning on using a dart little m block. will I have to use a small base circle cam to clear the 4" stroke? if so, whats the biggest stroke you can use with a regular cam? whats are the disadvantages to a small base circle cam? and lastly, what are the pros and cons of h beam rods vs i beam rods? does one offer more cam clearance? is one stronger? thanks
Race Director
Joined: Sep 2000
Posts: 17,298
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From: The Top of Utah
Since a 406 is merely a .030",over bored 400, rod clearance issues will be at a minimum. Stock 400 rods clear the stock 400 cam. Most 406 builders opt for 5.7" rods, or longer. Even stockers will clear a stock cam with a little bolt head grinding. With a 4" stroke, it depends on the rod you select. Some "stroker" rods may clear. The interference between the cam and the rod is at the big end of the rod. Beam type, "H" or "I" is not a factor.
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Melting Slicks
Joined: Dec 2001
Posts: 2,025
Likes: 1
From: Billings MT
I have the SCAT 6.0" H-beam "stroker profiled" rods in my 406. I am using a standard base circle solid roller cam (XR-280R) without any interference issues. The oil pan rails did need a fair amount of clearancing to clear the 7/16" cap screws.
Melting Slicks
Joined: Jun 2001
Posts: 2,429
Likes: 14
From: CA
If you are going to build a big SB with a Dart Little M, why not use the Dart Iron Eagle? It's designed after the Rocket Block, which was designed for big stroke applications with a raised cam. You wont need to worry about pan rail clearances either. IMO, worth the extra $300-$400
http://www.sdpc2000.com/catalog/790/...gle-Blocks.htm
http://www.sdpc2000.com/catalog/790/...gle-Blocks.htm
Last edited by 71coupe; Feb 22, 2005 at 04:14 PM. Reason: Fix link
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Race Director
Joined: Sep 2000
Posts: 17,298
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From: The Top of Utah
Originally Posted by red L98
on the stock block 434 we had to go with the smallest base circle they cam make .850 and that's small. the dart block motor we used a .880 base. the reason you use a small base cam is to clear the rods not the crank.
Originally Posted by red L98
and for rods it depends what brand you go with and how much power you plan on making. H beam eagles are stronger than the I beam eagles but the I beam crower are stronger the H beam eagle.
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Thread Starter
Burning Brakes
Joined: Jul 2002
Posts: 1,136
Likes: 100
From: Nova Scotia
71coupe, I dont think using and iron eagle block is worth it. because of the taller deck height I would need different headers, intake manifold, and timing chain/belt, and im not sure if the accesories would all bolt up. If I wanted to go through all that Id just go with a big block.
red L98, did you NEED to use a small base circle cam for the dart 434? Im assuming it was a little m. what is the normal base cirlce?
red L98, did you NEED to use a small base circle cam for the dart 434? Im assuming it was a little m. what is the normal base cirlce?
Team Owner
Joined: Apr 1999
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From: Reno Nevada
2024 C3 of the Year Finalist- Modified
Yes, you want to run the small base circle cams like the ones from Crane cams. My last two measured 9.030 and they were sleaved so you could use the standard dist. gear. You will not have the clearancing problems
You buy forged rods you need for the HP. Like lightweight I beam forgings 580 grams from oliver are only good for sub 600 hp where the Carrillo and others h beam ar good for 850 hp rating. Like my 6 inch H bushed rods from Manley weight 685 grams.
another thing to look at in these aftermarket block is the journal size. I went with 350 mains to get a lighter 4 inch stroker crank.
I went with the standard bore for 427. I didn't think that extra few inches to 434 was a big deal. Motors equivolently built and all you change in the cubic inch. HP stays nearly the same just TQ goes up as a function of the more CI
You buy forged rods you need for the HP. Like lightweight I beam forgings 580 grams from oliver are only good for sub 600 hp where the Carrillo and others h beam ar good for 850 hp rating. Like my 6 inch H bushed rods from Manley weight 685 grams.
another thing to look at in these aftermarket block is the journal size. I went with 350 mains to get a lighter 4 inch stroker crank.
I went with the standard bore for 427. I didn't think that extra few inches to 434 was a big deal. Motors equivolently built and all you change in the cubic inch. HP stays nearly the same just TQ goes up as a function of the more CI
Melting Slicks
Joined: Jun 2001
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From: CA
Hubes, you can get the standard deck in the Rocket or Iron Eagle block. The only things that would be different would be a longer timing chain & a wider pan. Everything else should bolt up. Even with a tall deck model, they sell intake spacers to allow any SB intake.
Thread Starter
Burning Brakes
Joined: Jul 2002
Posts: 1,136
Likes: 100
From: Nova Scotia
71coupe, i didnt know they sold the iron eagle block with a regular deck height, that might be a good option, thanks. do you know if standard small block accesories would work with the tall deck?
gkull, are you saying that a 4" stroke for 350 mains is lighter than a 4" stroke with 400 mains?
gkull, are you saying that a 4" stroke for 350 mains is lighter than a 4" stroke with 400 mains?
Melting Slicks
Joined: Jun 2001
Posts: 2,429
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From: CA
Scoggin Dickey has a list in one of their catalog that breaks down all of the non-standard items that will be needed. GM now makes the Rocket Block in a standard deck version that is less than the Iron Eagle.
Scoggin Dickey catalog pg If you had to sell it, I'm sure a real Rocket block on ebay would bring in more money than a Dart little M or an Iron Eagle. BTW - Monty had a tall block Iron Eagle & it's the way to go with a stroker to run longer rods.
Scoggin Dickey catalog pg If you had to sell it, I'm sure a real Rocket block on ebay would bring in more money than a Dart little M or an Iron Eagle. BTW - Monty had a tall block Iron Eagle & it's the way to go with a stroker to run longer rods.
Le Mans Master
Joined: Apr 2000
Posts: 7,562
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From: B'Ville NY
Cruise-In III Veteran
St. Jude Donor '05
With the Little M block, you can take up to a 440ci based on Dart's recommended max stroke and bore.
One of the advantages with the smaller journals is that they have less contact areas than the larger diameters which equates to less friction on your rotating assembly. I went with small journals on my crank and my rods (less bob weight at the journal end). Not sure how big a power difference between there is between the large/ small diameters but they're both readily available and free hp with the small is a nice bonus
One of the advantages with the smaller journals is that they have less contact areas than the larger diameters which equates to less friction on your rotating assembly. I went with small journals on my crank and my rods (less bob weight at the journal end). Not sure how big a power difference between there is between the large/ small diameters but they're both readily available and free hp with the small is a nice bonus