2105 vs. 7105

[unclewill]

Greetings,
I'm getting ready to start assembly of my 482 S.O. stroker, bought a 390 donor for some sheet metal and spare parts/cores, it has an Edelbrock intake which I assumed was a 7105 but, upon further inspection, appears to be a 2105 (stamped "Performer 390").
What am I giving up by using this intake?  Can it be easily modified to perform more like a 7105?
Heads = BBM alum, Comp 292H cam, ~10.4:1 comp., est redline = 6200.
1969 Torino Cobra, ~3500 lbs, CR 4-speed, 3.50 rear, hp street cruiser/some strip, looking for BIG midrange torque 2500 -5500rpm.
Thanks ahead of time!

[bn69stang]

you would giving up a lot , you need to step up to a blue thunder intake , or a performer rpm .. the regular performer is not for making power imo , i think you would choking your 482 inch motor .. Bud

[My427stang]

At least 40 hp IMHO, maybe more

[unclewill]

I also have a brand new Blue Thunder (or Dove?) 4X Weber manifold sitting in the closet.  It will probably cost me at least $3k to get it set up to run, I doubt it will fit under the ram air hood, and it may be a pain to tune...but Jees, it is tempting to run the 2105/850 dbl pumper until I sell my S.O. long block then take the plunge on the Webers...I read somewhere the Webers can't support 482 cubes - anyone care to chime in on that one?

Also, the car is relatively heavy and midrange torque is my goal.  Perhaps the high rpm hp loss would be mitigated by higher port velocities boosting torque?
Are the heads the limiting factor or the intake sub-6000 rpm?

[jayb]

On the Webers, there is some truth to the cubic inch statement.  However, its not so much a cubic inch limitation as it is a horsepower (airflow) limitation.  The 48 IDAs will start to loose out in horsepower over about 550, to something like a Victor with a Dominator.  Having said that, the Webers are FABULOUS for midrange torque.  If you have a copy of my book, take a look at the graphs.  The Webers slaughter anything else in the midrange, even with a big cube motor.

[cammerfe]

As an additional comment, it is entirely possible to use your manifold and install EFI units instead of carburetors. The EFI units come in various sizes so it should be possible to 'have-your-cake-and-eat-it-too'. I have switched from regular carbs to Webers to FI several times, and can attest to the mid-range torque available. And switching to fuel injection removes the 'hitting-the-wall' limitations of the Webers.

You may find it necessary to open up the runners on the manifold to get air-flow capacity to take full advantage of the EFI.

KS

[unclewill]

I just pulled the 2105 off the donor 390 and man does it look wimpy!  I guess I'll be ordering a 7105 tonight...oh well, another $500 down the tullet!
Hopefully I can get a few bucks for the 2105 + other unneeded parts from the 390 - anyone want a pair of C8AE-H heads?  LOL!!

I'm stuck between selling the Weber manifold and taking the plunge.  They just look so cool!  EFI is tempting too but the cost starts getting ridiculous!  The car is a factory R-code Ram Air car and I still have the air cleaner assembly installed...it's hard to let go...

Thanks for the advice, guys, much appreciated!

Here is some side oiler noise to make your day:
https://www.youtube.com/watch?v=N5w1c6CMk80

[My427stang]

Smart move for a new intake, but if you go RPM realize that it puts the carb to the rear a bit.  Not sure how the Ram Air will work, may want to consider Blue Thunder or getting a Holley Street Dominator and working it a bit.

As far as the "more torque with smaller ports" unfortunately the Performer just is old tech and small stuff, it doesn't win anywhere on anything over 360 cid in my opinion.

[bn69stang]

Keeping the carb in the factory location is why i opted for the blue thunder , i have a shaker and the hood was cut already . so go over your ram air stuff before you buy .. Bud

[unclewill]

Thanks for the advice guys, I'm actually more concerned with the height of the carb than the fore/aft location.  I will need to ponder the choice of intake over the next couple of days...

[bn69stang]

The blue thunder is slightly taller than the ford aluminum p i intake , i am able to run a small insulating spacer between intake and carb , and not push it into the bottom of the hood , my shaker set up that is ..Bud

[unclewill]

How about the RPMs carb pad height?  The 2105 has a 1" spacer which I'm saving for another build.  The Offy 360 on my 427 has a ~3/8" phenolic spacer which I will use if there is room.  Is carb heat soak a big problem without a spacer?  I'm planning to put the splash tray in the lifter gallery to keep the oil under control.

[bn69stang]

If i remember correctly , the rpm is slightly taller than the blue thunder . the rpm is 5.46 inchs tall .. Bud

[unclewill]

Thanks for the info, Bud.  I just found a street dominator in my local paper, going to make an offer later today...

[My427stang]

Thanks for the info, Bud.  I just found a street dominator in my local paper, going to make an offer later today...

I really like those intakes.  Should work well for you, but could benefit from some well thought out porting.  Regardless, should be within spitting distance of the RPM and well above the Performer 390 intake even as cast