Blown 406 ??????

[xl883lo]

I can't make up my mind. For a long time I had played with the idea of putting a B block 383 in a 72' Demon. I am now leaning towards an A block 406. I have always liked the idea of a square motor (4x4) and this would have obvious advantages in an A body.

The questions are........

1)What experiences/comments does anyone have concerning the 406 configuration in general.

2)If I got completely outrageous and put a blower on it (other than standard blower issues) are there any problems specific to this set-up that I might encounter.

3) Any comments regarding what someone might think the best all around set-up (cam,intake etc.) is for a 406 if I decide to go mild/streetable.

TIA

[kick_the_reverb]

Problems that might be encountered with blowen stroker small block:
Pistons - you'll want forged pistons with beefy ringlands and enough meet on them to withstand boost. That contradicts with the need for a shorter piston for the stroker.
Too much power for the stock block - depends on many variables, but you could face that situation.
Heads - say you are really serious, and you want to get the maximum out of the blown stroker - you might need more expensive heads, as production style heads are marginal on strokers. Of course, if you get really good heads, and make a lot more power, than you increase the chance of reaching the block's limits.
Traction - I heard that since the strokers already have tons of low-end torque, adding a blower really makes them hard to hook. Of course, it depends on many varaibles, including the type of blower (roots = more low end torque for example).

All of the above are just general concerns. Quite a few people have centrifugally blown Dakotas with magnum strokers, so it's not impossible to do.

Good luck,
Ran

[1973Swinger]

All you have to do is use all forged internals and do not use a stock block, use an R3 block. Keep the compression down, use Cometic gaskets, etc etc. In other words, just use the best parts that you can afford and dont skimp out otherwise youll be paying to rebuild it again. It will not be a cheap build, but it would be cool. I have a buddy that runs a blown 383 stroker (Chevy) in his 4x4, and that thing will smoke all 4 super swampers in 4wd. Good luck!

[dust]

I have not seen a 400+ cu in small block with a blower, do they make low compression pistons for that?

[BJSracing]

Hell I would be more concerned with actually trying to find a blower for a small block. I haven't seen any intakes for them as of yet. I had the thought of doing a blown small block but never did find what was needed to do it.

[kick_the_reverb]

I'm not aware of blower pistons for a 4" stroker. It will be easier to do with a smaller stroke crank.
It's not hard to find a small block mopar blower intake, it's just expensive. I got a used one for $450. New ones start at $800. There's an older post here about an Australian guy (or NZ, sorry) that casts blower manifolds. The price was around $1200.
Of course a racing block is a good idea with so much power. It's essential if you're going to actually use the power.

[xl883lo]

Originally Posted by 1973Swinger

All you have to do is use all forged internals and do not use a stock block, use an R3 block.

What are the advantages of an R3 block over the early 340 block with the 4 bolt mains,thick bores and deck????

[1973Swinger]

To begin with, they never made a 340 with 4 bolt mains. The T/A blocks webbing is thick enough to do so, but if you have a REAL 340 T/A block and you alter it, you are flushing a bunch of money down the crapper. Here are the specific advantages of an R3, I got this off of Moparts, this is the LA R3, there is also a Magnum R3:

Building on Mopar’s heritage, the “R3” race block family offers the latest in design technology along with the options to meet your specific needs. All of these blocks feature:
• Process-controlled castings utilizing high-strength cast iron and a computer-controlled stress relieving process
• 100% CNC machining with full statistical process control
• Thick deck surface and 6-bolt cylinder head attachment (48° blocks) for improved sealing and reliability
• Rough bore at 3.900" with various options that provide over-bore capacities up to 4.220" (in siamese-bore versions)
• Various options that provide deck height potentials of 8.900" to 9.560"
• Tappet angles in both 59° (stock) and 48° (improved valve train geometry) are available (59° blocks are not recommended for use with roller tappets)
• Thicker main webbing and pan rail for improved rigidity
• 4-bolt mains in ductile iron, billet
• 318/340 main journal size
• Machined for pre-Magnum head oiling, and dual engine mounts (Magnum and “LA”)

[xl883lo]

Originally Posted by 1973Swinger

To begin with, they never made a 340 with 4 bolt mains. The T/A blocks webbing is thick enough to do so, but if you have a REAL 340 T/A block and you alter it, you are flushing a bunch of money down the crapper.

I was looking at a new mopar "repo" 340 block the other day and it had 4 bolt mains........the guy told me it was patterned after the early TA block. Since I have never worked on an early 340 I assumed it also had 4 bolt mains.

[1973Swinger]

Originally Posted by xl883lo

I was looking at a new mopar "repo" 340 block the other day and it had 4 bolt mains........the guy told me it was patterned after the early TA block. Since I have never worked on an early 340 I assumed it also had 4 bolt mains.

Nope, and if that block was built by Mopar, someone else added the 4 bolt mains. Even adding the 4 bolt main caps to a small block Mopar doesnt make it a "true" 4 bolt main engine, as you can only put the 4 bolt caps on the center 3 mains.

[kamstra]

The stronger head bolt configuration of a Big Block B or RB is better suited to a blown application. Blowing head gaskets may be more likely in a small block versus big block

[kick_the_reverb]

The head gasket problem could be solved today by Cometic or other MLS type of gasket. Of course the surface finish should be suitable. Even better is a race block with 18 head bolts and a suitable head.

[65TerrorCuda]

Here's the small block intake, it was $1100.

[sanborn]

A lot of what you need depends on what you really want. If you want a very mild engine, with a mild supercharger===then you can get by with a lot of stock parts. But if you want something that can scare you===you need good parts. And of course, your budget will also determine what you can really do.

My comments are based on using a Roots Type supercharger(4-71/6-71/8-71). For a mild setup, use of a 4-71 has advantages. It's smaller, can be adapter to most single four barrel intakes, which allows standard water plumbing, standard ignition. It also allows v-belt pulleys. A single four barrel (built for a blower setup) is all thats needed, boost will be low(5-10 PSI) so just good stainless valves are all that's necessary. Pistons should be forged(custom blower pistons), moderate aftermarket rods are necessary, but standard steel cranks and a two-bolt block is OK. Studs are necessary for both heads and crank. Heads should be as good as you can afford===aftermarket is preferred like Edelbrock. I think you would be disappointed in X,J or the like===unless they are well modified. And if you just want a 6-71, that's OK. It just requires an aftermarket maniflold or serious modification of a 2X4 intake. An engine like I describe will produce in the 550HP range.

If you want something that increases the "Pucker Factor", then you need to go further. A race block would be a cheap investment, four bolt, etc. Studs are necessary on both the heads and crank. Forget about the stock crank or even a MP 1150 crank, use only a 4340 aftermarket crank. The rods will need to be serious, no Eagles, CATS, etc. Crower billet, Oliver or Carillo is necessary. Pistons must be custom blower units. Valves must be Manley Severe Duty or equivalent. MSD ignition with a 7AL box is necessary. You can overdrive the 6-71 5% or even 10%===this will produce about 20 lbs. of boost with W2s. Heads should be W2===less head will restrict HP too much. The same for carbs, two worked Holleys are the minimum. Less will restrict HP. This engine will produce about 700-740HP.

Unless you just want to build a 400+ engine, I wouldn't spend the extra $$$. If you need more torque, just increase the blower ratio. To go further, you will need W7,8 or 9 heads===then the sky is the limit on HP.

[Lil_Bee_R/T]

Originally Posted by xl883lo

I can't make up my mind. For a long time I had played with the idea of putting a B block 383 in a 72' Demon. I am now leaning towards an A block 406. I have always liked the idea of a square motor (4x4) and this would have obvious advantages in an A body.

The questions are........

1)What experiences/comments does anyone have concerning the 406 configuration in general.

2)If I got completely outrageous and put a blower on it (other than standard blower issues) are there any problems specific to this set-up that I might encounter.

3) Any comments regarding what someone might think the best all around set-up (cam,intake etc.) is for a 406 if I decide to go mild/streetable.

TIA

i have a buddy that knows everything you can do to that motor and if he dont he will definatly tell you where to go to get it. ill PM the Number to you,kk.

[go-fish]

Call www.thesuperchargerstore.com . They've been doing the supercharger thing for a little while. I got my Pro-Charger D1-SC from them and I think centrifugal is the way you should go. You said you wanted to doan A block, as in a Poly 318? I'd go for a late A , LA, 340 or '71-'75 360 as they are the strongest of the LA family.
Also, forged rotating assembly, 114* LSA cam, 8.5 compression ratio, blowthrough carb, and if you wanna make 450+HP get a Hughes Engines main stud girdle, stay away from the four bolt stuff unless it came from the foundry that way.