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Need advice- New 225 build street/strip blown/EFI Duster
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Author:  chrisnben [ Sat Jan 21, 2017 9:10 am ]
Post subject:  Need advice- New 225 build street/strip blown/EFI Duster
Hi guys,
In the beginning stages of a new Slanty build for the Murder Duster. I'm not one to leave well enough alone (go fast or go home) and like to be different- hence the blown 225. I've built too many SBM and BBM in A,B,E bodies- well it's time to embark on the 225!

I'm needing suggestions for a hot street car- regarding cam specs, which intake, header tube size & pipe size, etc. So chime away! I think the EFI will tame the idle down somewhat.

Static compression at 9:1, boost 6-8#, could run E-85 fuel.

I already have sonic checked the block and got 3.504" KB 268 hyper pistons, Molnar 7" H-rods= 239 CU IN. The head is getting massaged/ported, bigger valves. Won't mill it until I know cam specs. Still have to mock up the rod/piston to see where the deck is, etc.

The EFI is the FiTech 4- 600hp unit.
Some specs on the Duster:
potential weight- 2900#
worked 904 auto (converter not purchased yet)
8-3/4 rear with 3.23 gears
27" rear tire
[img][img]http://i265.photobucket.com/albums/ii228/chrisnben_bucket/1972%20Duster/duster5_zpshhow1if7.jpg[/img][/img]
Author:  slantzilla [ Sat Jan 21, 2017 9:59 am ]
Post subject: 
Not really an expert, but a blown motor won't want a lot of duration or overlap.

Unless you want to build headers your choices are somewhat limited. A set of Hooker Super Comps will be about your best choice for an off the shelf part.

You may end up wanting a touch more gear to get the car moving, but the nice part is you won't have to RPM the crap out of it like an N/A motor.

Converter will be kind of a crapshoot. Again, you won't need one that flashes to the moon, but it will have to have enough to let the motor rev into boost. I have seen many small blower motors on a chassis dyno. The torque curve actually looked like a right angle. Nothing until they got on boost, then flat as a table top until you shut it off. :D
Author:  Dart270 [ Sat Jan 21, 2017 10:18 am ]
Post subject: 
Sounds like fun, Ben.

We will need some specs on the blower/intake system. What size blower?

My boost experience is with a turbo, which really does not like overlap and my cam is just one tiny step above stock. I expect you can run quite a bit more cam with a blower. I would probably run a cam in the 230-240 @ 0.050" range with about 0.500" lift. Big headers like Hookers sound good. Hard to get Clifford headers and you can fit the Hookers on your late A-body.

The head is where you should spend the most $$ and time (after the blower). Bowl porting is best, and the main ports do not need much work. Be careful not to take out the hump between I and E on the same cylinder as you can hit water there. The bowls can be enlarged a lot and that makes a big diff. I knock the guides down most of the way to flat on the E ports and plenty but not that much on the I ports. Don't touch the floor except to remove casting flash. If you want to make the main ports bigger, go taller but not much (of any) wider.

What are your performance goals? Desired 1/4 mile time, HP, or other?? How many street miles? Much hwy driving? MPG a factor?

Thanks,

Lou
Author:  chrisnben [ Sat Jan 21, 2017 11:18 am ]
Post subject: 
Quote:
Sounds like fun, Ben.

We will need some specs on the blower/intake system. What size blower?

My boost experience is with a turbo, which really does not like overlap and my cam is just one tiny step above stock. I expect you can run quite a bit more cam with a blower. I would probably run a cam in the 230-240 @ 0.050" range with about 0.500" lift. Big headers like Hookers sound good. Hard to get Clifford headers and you can fit the Hookers on your late A-body.

The head is where you should spend the most $$ and time (after the blower). Bowl porting is best, and the main ports do not need much work. Be careful not to take out the hump between I and E on the same cylinder as you can hit water there. The bowls can be enlarged a lot and that makes a big diff. I knock the guides down most of the way to flat on the E ports and plenty but not that much on the I ports. Don't touch the floor except to remove casting flash. If you want to make the main ports bigger, go taller but not much (of any) wider.

What are your performance goals? Desired 1/4 mile time, HP, or other?? How many street miles? Much hwy driving? MPG a factor?

Thanks,

Lou
Lou,
as you know, the 700r4 will most likely go behind the 6. I'm not sure of the gears in it- I'll investigate.

I was thinking similarly on the cam: 248/243 @.050; and 494/480 lift. I'm assuming roller rockers will be in order?? Or stockers?

The blower pulleys will make 8#. We do have the option of air/air intercooler, but it isn't in the kit. The intake most likely opinions say the short Clifford 45-4500wh is the ticket.

Performance goals- well ALOT. I don'tthink the combo will be "overpowered". I've had several 500-700hp cars. So whatever she makes- or CAN make and be well-mannered on the street. I don't plan on trying to make 20# boost, etc.- plus I'm not sure the hyperutectic pistons can handle more than 10#. I cheaped out on the $900 forged pieces. KB gave me 8 pistons/rings for $350.

I'm hoping to get SOME MPG under cruise/hwy with the O/D and 3.23's. Maybe I'll be surprised?? 18mpg, I don't know.

In a perfect world with this set-up- not even sure! 1/4 mi times, mid 11's would be my guess. I'm sure you know of Steve Nitti's 10.80 sec. gold Duster from Minnesota. But that is a high stall, 20# boost race car with turn signals.
Author:  DusterIdiot [ Sat Jan 21, 2017 1:39 pm ]
Post subject:  Deeper...
Quote:
I'm hoping to get SOME MPG under cruise/hwy with the O/D and 3.23's. Maybe I'll be surprised?? 18mpg, I don't know.
With an OD you can go deeper than that, especially with the taller tire... something in the 3.55-3.91 range will allow get up and go in the first 3 gears, and provide mileage in OD... final ratio on a 3.23 in OD would be close to an A904 with a luggy 2.56 rear gear... 3.55 will be about 2.8 ...3.91 about 3.12 final ratio...
Author:  Dart270 [ Sat Jan 21, 2017 1:53 pm ]
Post subject: 
OK, your answers help. Will contemplate further.

Mid 11s sounds ambitious on 8#, unless you have monstrous head porting or lighten the car quite a bit. Clifford 4V intake is probably the best ticket.

Lou
Author:  bboogieart [ Thu Jan 26, 2017 2:01 pm ]
Post subject: 
Howdy neighbor.
Just north of Green Bay here.
No help with the build but really like the "Blown" aspect of this car.

I am curious about what blower you are using.
Got pic's?

I have some old mopar junk.
Let me know if I can help you with anything.
Author:  bboogieart [ Thu Jan 26, 2017 2:06 pm ]
Post subject:  Re: Deeper...
Quote:
Quote:
I'm hoping to get SOME MPG under cruise/hwy with the O/D and 3.23's.
With an OD you can go deeper than that,
and really should.

I am also curious about mating the 700r4
Motor-plate like a big block?

Nothing would make me happier than using an easily found hydraulic over-drive auto for my buggies.
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