6-71 roots
 

Taking my 383 in my 1968 Newport and boring it to a 430. Is this too big for a 6-71 blower?

I don't think you will get 45 cubes just by boring. A stroker kit would be needed.
Blower is doable at any size as long as it is built as a total package

Please tell me this question is a joke. You DO know that 4- and 6- 71 blowers are what were traditionally used on AA/F cars?



I spose if the blower was loose enough and underdriven enough you could get it "small" enough that the engine would be "too big" for the blower, but I rather doubt it!!!!

a friend ran a blower on the street. he was told not run the set up that was ran on a race engine, ie pully sizes not faster than 1 to 1. cant remember what timming to run, just dont over do it.

I was told that 426 ci is max a 6-71 can do, any bigger I should go 8-71. Will be stroking as well.

Anything will work but using a small blower it has to spin faster to make the same amount of air move through & will become supersonic & create a lot of turbulence / loss of efficency so I agree using a larger blower & turning it more slowly is a better way to go.
BDS has some of the most efficient blowers available & would be happy to discuss what you need , I assume you will be over 500 CI but not sure how high you want to run the engine RPM wise .

Here is what I have. I just want to confirm that I'm working with a good combo.

1-Hampton 6-71 blower
2-engle cam


Lift-intake 515
-exhaust 535


Duration- intake 276
- exhaust 285


Gross cam lift- intake 342
- exhaust 355


Duration @ .050" - intake 230
- exhaust 238


Lobe centres 112


Edelbrock RPM aluminum heads with 88cc chambers


Mopar 383 block bored 30 over, and stroked


Scat rotating assembly, forged of course


Edelbrock 670 carbs (2)


Edelbrock 150gpm fuel pump


I am looking for headers with a 3" collector as I plan on running 3" exhaust


Looking at a 3 speed tranny (727) built for 750 HP (any suggestions)?


2500 stall converter


Not sure if I will need to intercollegiate the blower


My redline will be 5500 even though my power band exceeds that (is actually 2000-6500 powerband). I am not looking for a high revved, just a high torque machine off the line.


Rear end gears will be 4.11 in my 8-3/4" rear end


Front disk break conversion (any suggestions)?


Want to cram the widest rubber I can in the stock configuration


Will be installing traction bars, but rest of suspension will remain stock this year, but plans are to install air ride system as this will be a bit of a low rider.


Opinions: car will be a sheet metal finish with black powder coated wheels. Interior is black which I am taking out of another Newport.


What gauges will I need to monitor blower and overall performance?
(Thinking boost, oil, tach, temp)


Is a waste gate a good idea?


Looking at an MSD ignition with boost control.
High flow water pump, and high volume oil pump.


Should I go bigger alternator if I am installing a sound system? 2000w


I think that's it for now. If I am over looking anything please let me know. I am not an expert, just did my research and have the cash. This project I am involved with building. My previous project was hired out.


Thanks guys,


Newport

Sounds doable , you want a cam with with a wide lobe seperation usually 112-114* is where you want to be so the cam will work . You did not list pistons so I have no clue what your compression will work out to .
Building a 727 for this is no problem , you may want to lok at the 518 with OD though , same as the 727 + the 4th gear OD .
I would use TTi headers .
I agree with the choice of guages .
The intake will have a blow off plate , waste gate is not nessisary though .
The Fuel system is critical , you do not want to go lean @ wot make sure you have even 2 pumps , 1 to each carb or a big pump & line split at the carbs .
Be careful with water pumps , some of the alum housings are very restrictive & will cause more heat not less , get a good quality one & a large rad to keep everything cool .
High volume oil pumps are not cool with a stock pan , I would use a high pressure but stock volume Melling oil pump .
Check with scarebird for the disc conversion , they should have adapters
Skip the traction bars , just add 1/2 leafs going forward & clamp them .
It depend what alt you have , most had the small 60 amp alt , you can use the Mopar 100 amp Alt but you need to connect a bypass from the alt across the the battery terminal on the start relay so 100 amp is not going through your ammeter & bulkhead plug otherwise everything will melt !!
Hope this helps

i don't think that 518 will fit the b motor isn't the bolt pattern different between la and the b? he will need a adapter kit.

Thanks guys for the responses! Good to know that I am on the right track with what I am doing. I did a lot of research, so I am glad it will all pay off. I am aiming for compression of 8.1. No higher.


I'd like to get it dyno'd to see what I am getting. As long as its close to 600 I am happy. Still want to use pump gas of 94 octane with no additive.


Thanks again!


Newport

yes he needs an adapter plate for the 518 as it was never bolted to the big block , simple to do though & with the gearing & RPM limits he will not have a lot of top end speed without OD

i agree that's the only reason i waited on my 3.91 gear until i could get the 518 swapped in, driving would be no fun with all the rpm's ol girl would be turning.
in over drive she drops down to a reasonable rpm at high way speeds it's a tall gear that 0.69, od and with the lock up an extra 2-8 hundred rpm's,
the speedo cable, and the trany gear for the speedo is the only thing that i'm waiting on,
i might suggest a different trany mount though.
cruising around 40-45 mph is 2000-2200 rpm's when the od is engaged the rpm drop's another 1000-1200 rpm put's me back in the ball park for that high way cruising, then the lock up is nice for cruising just above that 2000 rpm,
i like the feel of the direct lock up the car is a new monster to drive.
i know TCI has 4 to 6 speed auto tranies good for 800 hp and i think they are made for any block size, i think they are using a independent bell housing. :)

Is there a different gear in the back I should use besides a 4.11? I am ok cruising at 2500 rpm on the highway and doing tops 140 mph is plenty for me. This is a street machine, and I have bad luck getting pulled over! I will look into the 518 tranny. I just want to build this once, and do it right the first time. I am not on a budget so cost is no issue.

with 4.10 gears @ 5500 RPM with a 28" tall 275 60 15 tire your speed will be only 111 mph
with a .68 OD & everything else the same your top speed will be 165 mph

now that's what i'm talk-in about......:gone:

you have to learn the art of driving fast with-out driving fast !
there is a time and a place for every thing and it's not when we think it is.
only when it is...!

Thank you folks. I think an OD tranny is what I'm looking for.

Found company in Toronto, Ontario who builds an overdrive for a 727 or any other mopar tranny with no modification. Cmk transmissions.

Correction:

SMR Transmissions

O/2 sensors to monitor the air/fuel ratio.It's real easy to go too lean and have 2 meltdowns. 1st the engine,,,,,,,,,,,,,,then you:naughty:

rich is far safer than lean !!

O2 sensors? How? Where? Why? And for what vehicle do I get them for?

You buy a Wideband AFR gauge. You dont buy an o2 sensor for any car , It comes with the o2 sensor, bung, gauge, ect. Weld the bung into the exhaust, and screw in the o2 sensor. Hook the gauge up. Simple.

It's used to monitor the AFR's of the engine. (Rich or lean.) You SHOULD have one on ANY forced induction motor.

You don't need a wastegate on a blower set up.

You should run a BOV of some sort though to help prolong the life of the forced induction component.

there is a gear vendors overdrive unit that can be connected to the 727

the GV is a simple swap as well & a tough unit

Have changed plans a bit. Still going 0.030 over, but putting a 489 stroker in it as well as the blower!

Any updates on this project??How 'bout some pictures!:doh:

Update
 

Still working away at it.Acquiring all the parts first then doing the build over the winter. I've done a lot of research and have learned oh so much. Reading my original post for this thread, I was such a newbie.


I decided to stroke to a 450.
I still need rockers, and timing chain, and oil pump, and water pump, etc. but the bulk of it I have.


Will definitely take pics along the way and will post them.


Thank again to all who have helped me thus far.

`that 165 mph is only theoretical. Street blower I would re consider and maybe use a 3.55 gear
IF YOU ARE really going to build a blower for the street ? WHY not get an aftermarket block and build a 600+ ci and build a mountain motor

My 2 cents on gear ratio...... Go the 4.30....Its a happy starting point for your project for street or strip...
A good solid 6.5-7.1 base motor will work good for your blown project.... Just dont boost it to hard.
Oh and a 6-71 should work just fine. Do you have the blower and pulley and brackets setup already?

Keep up Posted.... :)