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Discussion Starter #1
I kind of think I am not getting the full potential of this 349. Don't get me wrong, this sucker breaks things all the time. It has a lot of power. When my friend and I started building this little beast I wondered if the heads were too small. Maybe someone can tell me different.

I was wondering if I would be better off getting a set of better flowing heads or just port mine. I think I would have them professionally done since I don't do this for a living. I think something like this is best left to the pros. One slip of the high speed grinder and hello water jacket! Here is my combo now.

PBM Scat forged crank
PBM Scat rods
Main stud girdle/ windage tray
JE dished pistons
Lunati roller cam (560 lift)http://www.fordmuscle.com/forums/vbimghost.php?do=displayimg&imgid=1478
Weiand 174-6 psi boost
TFS 170cc aluminum heads 2.02/1.60/61cc
Carb: ProForm 750
Ford racing shorties 1 5/8"
toploader 4 speed
9" with 3.55

Thanks in advance!
Mike.
 

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Keep in mind you cannot compare the cc of the twisted wedge to the like of an AFR. The TFS TW port is shorter so it makes the cc look smaller than it really is. The cross section of that head is very similar to an AFR 185. Sure they could still be too small and could be holding you back. Just didn't want you to get too caught up it the 170 cc port measurement.
 

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I was thinking that too... you should try to fit some 1-3/4 long tubes in there.... accufabs, FPA, etc...
Sounds great though... but it could use some breathe.
 

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Discussion Starter #5
Sounds great guys. It looks like I might pull them for the winter and have them ported. I need new headers anyway. Mine are the Ford Motorsport shorties. They are touching my steering box on the driver's side and almost the shock tower on the passenger side. I bet you can't fit a credit card in between. I need headers that dump a little more as they come off the exhaust port to clear the towers.
 

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I think the headers are holding you up the most. As was said, those heads have an intake port that has been SHORTENED 0.400", so cc measurements won't directly compare. This 170cc head has a cross section that would probably more directly compare to something around 185cc.

From your videos, it seems you have all the power you can use on the street the way it is. LOL! :)
 

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A GOOD exhaust with 3" mandrel bent pipe and -see through- mufflers will also be mandatory in getting the most out of your blower. You'll probably have to cut and weld sections together to do it. On tip, Summit has their own 'generic' X-pipe that comes with four 45º mandrel bends to hook it up for less than $100. It's almost worth buying the kit just for the bends, LOL! Speedway motors also has a lot of mandrel bent tubing.

If you need tailpipes, you might run 3" back to some 3" mufflers, then weld some 3-hole collector rings to their outlets, and use ordinary header reducers to make the tailpipes REMOVABLE. ;) 2-1/2" mandrel bent Flowmaster tailpipes are made to fit early mustangs, work well, and are only around $100/pr.

3" madrel bent back to 3" see-through mufflers, and removable mandrel bent 2-1/2" Flowmaster tailpipes.

Hey, you're blowing all that extra air into the engine... ya' gotta' get it out!

From the following pic from your website, it seems your exhaust has a LOT of room for improvement!



Good Luck!
 

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Agreed. The exhaust (and cam LSA on the street) is your pinch. One build was a 393W with 8.0:1 and the only heads handy were a new set of TW. At 15psig through four cheapie quiet 3" turbo mufflers and dogleg outlets, it dynoed at 674 hp at the rear wheels, and 749 retimed with H2O. That would be above 850hp at the crank. The TFS heads were only port matched on the intake side, springs changed and bolted on, as a head change was anticipated. Later heads were Vic Jr. 70cc types, but only to allow similar numbers on pump gas with the big chambers and perhaps better quench with the pistons used.

Have you tuned it for fuel and spark on a dyno?

FWIW,
David
 

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Discussion Starter #11
Hi David,

Thanks for the response. Dyno tuners are as rare as hens teeth here in Alaska. I don't know of any. I did find a guy who used to tune carbs. He is going to dial mine in and re curve my distributor next month. There is a dyno in Anchorage and I'm going there on the 20th. It's only $100 for three pulls within 30 minutes. I will ask them if they can dyno tune the engine as well. BTW, what is LSA?

Mike.
 

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LSA is Lobe Separation Angle. Combined with long duration, tight LSA can cause a loss of low and midrange power with a supercharger, and turbo's too but for different reasons. Generally, you want the widest LSA you can get, which would be around 114° with the style cam you have without going custom.

However, before changing cams, I'd go for the tuning. There is usually a lot of power hiding there. Call ahead to be sure the dyno is using a wide-band AFR sensor, and if it's not a tailpipe clamp sensor, get a bung welded in your crossover pipe before you go. Get the dyno operator to print the Air:Fuel ratios as you make your pulls. Change carb settings between pulls if you can to correct, but at least be sure it's not running too lean or rich. If you have a couple hundred bucks laying around, definitely get a dedicated wide-band AFR (WBO2) setup to run in your car all the time. Cheap insurance and great for tweaking the tune. Richer than 12:1 can help suppress detonation, but will cost power doing it - especially if not needed.

Attach a vacuum gauge to a carb baseplate nipple that will read vacuum under the carb. If the vacuum gauge shows more than 2" vacuum at WOT and peak power, your carb is too small. Also be sure it's a properly modified carb for blowers with power valve manifold pressure referencing (tube from lower manifold to PV chamber) and the power valve selected properly (idle vacuum divided by two = power valve number).

Finally, your ignition timing usually holds the greatest power. The dyno operator should know how to make timing test pulls to zero-in on your MTBT (Minimum Timing for Best Torque). Best timing is NOT the most you can use without pinging. If you get det without reaching your MTBT, you need better fuel, water injection, intracooling, or a combination. Just retarding your timing will allow driving without det, but will cost power. A lot of power.

You've spent thousands getting to where you are - dyno tuning is a cheap way to unleash the ponies hiding in there and it's cheap insurance too. Have fun!

David
 
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