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Author
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Topic: How much can you squeeze out of 351W heads
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Dubz
Gearhead Posts: 1718
From: Manitoba Canada
Registered: Oct 2002
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posted 03-12-2005 07:06 PM
   
What is the max hp potential of 351W heads (74 heads with 60.9cc chambers and stock 1.84" intake and 1/54" valves), or the cap at which they start to really hold back the rest of the combo? Would it be around the 350 mark, or a little higher/lower?how much would enlarging the seats for 1.90 or 1.94 and 1.6 valves be worth as far as hp potential?
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rustang@home
Journeyman Posts: 94
From: Clarion, PA
Registered: Jan 2004
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posted 03-12-2005 07:12 PM
I'd say with 1.94/1.60 valves...good port job, and if you're living right, 450-475hp is achievable with the 351W
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1965stangracr
Journeyman Posts: 14
From: Clear Spring , Md.21722 USA
Registered: Jan 2004
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posted 03-12-2005 07:13 PM
I have gotten a set of stock 351w heads to go 12.30's in gregks mustang it depends what you have under those heads
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GregK
Gearhead Posts: 165
From: Clear Spring, Md
Registered: Mar 2004
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posted 03-13-2005 05:56 PM
Dubz just what Bobby said in above post. Acording to desk top dyno my combo was 349 hp.@ 5,000 rpm. That was about max with 1 5/8 headers going into 2 1/2 exhaust with Magna flow mufflers.------------------
1968 coupe 351W, Bored.030,Stock Crank, Stock Rods,Decked,KB Hyper. flat top pistons. Bullet Cam 231/[email protected]/.541 lift,Stock heads,RPM Air Gap,BG 750 Speed Demon,MSD Ignition,C4 Trans.,9" rear with 4.11 posi. best time 12.323 @ 106.80 mph in the 1/4
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Dubz
Gearhead Posts: 1718
From: Manitoba Canada
Registered: Oct 2002
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posted 03-14-2005 02:21 AM
If i were to keep the stock size valves, and get the heads mildy ported with some bowl work, and a 3 angle valve job, would they be up to the 400hp challenge? I'm not sure that the rest of the combo will be up to that anyway, but that's what i would like to shoot for.Also you can only mill .030 off before you need to mill the intake correct, or is it at .030 that you need to mill the intake? i should loose about five and a half cc with that much off right?
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sprcoop
Gearhead Posts: 373
From: Tucson, AZ usa
Registered: Jan 2000
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posted 03-14-2005 02:41 AM
My setup on Desktop Dyno says 329HP at 5500RPM with small tube headers (I'm assuming that would be correct for Hooker Competitions) with mufflers and goes to 351HP at 6000RPM when I go to open headers. Thats with stock DOOE heads (except for the screw in studs, being shaved and pistons taking them to 10 to 1 CR). Makes me think the exhaust is the bottle neck not the heads. Of course that's DD and I have no idea how accurate it is.
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Dubz
Gearhead Posts: 1718
From: Manitoba Canada
Registered: Oct 2002
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posted 03-14-2005 02:51 AM
What flow #'s are you using for the heads?
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74merc
Gearhead Posts: 1006
From: Demopolis AL
Registered: Jun 99
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posted 03-14-2005 10:06 AM
Engine Analyzer is much more accurate than DD. It has the option to put in real flow numbers on heads and such, actual numbers on port size, length and cfm, losses from accessories, low tension rings, low friction bearings, recommended timing...google Engine Analyzer 3.0, look for the free one. I have it on file here if you cannot find it.
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grego37
Gearhead Posts: 132
From: los angeles,CA,USA
Registered: May 2004
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posted 03-14-2005 10:36 AM
Go to aluminum.By the time your done investing all that money and time into guides,seats, valves,valve job, seals, porting and polishing, You could of upgraded to a set of new aluminum heads.
There are so many choices with 20+ companies out there making these heads. Most of them you can purchase complete ready to bolt on. You'll save on front end weight too.
I went with the TFS-R series out of the box bolt on's on my 408 and got 500HP, 500TQ with 9.8:1 compression and pump gas.
Weigh your options.Good luck
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Dubz
Gearhead Posts: 1718
From: Manitoba Canada
Registered: Oct 2002
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posted 03-14-2005 03:35 PM
found a set of used afr 185's, for the same price of getting mine milled/tapped/valve job/ported.hopefully this deal goes though and you guys won't have to hear me dealing with head choices again 
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Fastymz
Moderator Posts: 18703
From: Reno Nv USA MEM#1240
Registered: Apr 2001
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posted 03-14-2005 04:00 PM
quote:
Originally posted by Dubz:
found a set of used afr 185's, for the same price of getting mine milled/tapped/valve job/ported.hopefully this deal goes though and you guys won't have to hear me dealing with head choices again
I hope it works out for you.
If not then just start building up the short block and add better heads when you can. ------------------
oddly obsessed with big scoops on little Mustangs 65 coupe 351w C4 Big Boss 429 hood scoop,8" 3.40 TracLoc. My Pics
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sprcoop
Gearhead Posts: 373
From: Tucson, AZ usa
Registered: Jan 2000
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posted 03-15-2005 02:35 AM
Dubz, I didn't use "flow" numbers as that would probably require knowing what I was doing. I don't know what it takes to run a flow number test or even where to go to have it done. I just plugged in the 1.84 exhaust and 1.54 intake and used the "low performance stock heads/valves" option.
Single plane intake
Solid lifter cam
294/294 duration
108 lobe center
.544 lift
600CFM Carb
311CI (302 .060 over)
Mine do have the exhaust bump removed but I don't think that would qualify as "pocket porting". I was just saying that since if I only made it open as opposed to mufflers the HP jumped 22 so raw numbers would get at least 350HP out of stock 351W heads. This is on Dyno2000.
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Dubz
Gearhead Posts: 1718
From: Manitoba Canada
Registered: Oct 2002
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posted 03-15-2005 03:22 AM
Well when i entered the flow numbers from the fordmuscle head article for stock heads it doesn't look too well. Can only wack out 281 hp, gaining another 10 by uncorking the headers. Compared to 344 with edelbrock performers with full exhaust, all other things being equal. Seems like the heads are allready the weak link in the setup.The guy selling the afr's is looking for cash, so even though i spoke for them he's selling them to the first one at his door with the money. Being 2 hours away i can't get there till sat, so most likely too late 
Edit: And they are gone allready [This message has been edited by Dubz (edited 03-15-2005).]
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sprcoop
Gearhead Posts: 373
From: Tucson, AZ usa
Registered: Jan 2000
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posted 03-16-2005 01:44 AM
Dubz, I sure hope my DTD is closer than yours. To give you some hope the "300HP for $1500" recipe was with stock 289/302 heads and Alex claimed another 30HP with older (pre 73' or whenever the valves got smaller) 351W heads. I'm banking on real world experience per Alex. ------------------
Jerry Cooper
Candy Apple Red, 66' Coupe, Wide Ratio Toploader
9" 3.10 peg leg now, soon to be Traction Loc
302 Block on the Engine stand
Soon to be 300+ HP
15" Styled Steel Wheels
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Dubz
Gearhead Posts: 1718
From: Manitoba Canada
Registered: Oct 2002
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posted 03-16-2005 02:25 AM
In case you didn't know, the engine in question is a 351, with a horrible 8.4:1 compression with the heads milled, a 670cfm carb, edelbrock rpm air-gap which still falls into i guess a dual plane in DD. cam choice will be a 270H with 1.7 ratio rockers, hooker competition headers (most likely considered small tube headers i guess)
Alex's 1hp per 1cid recipie was also with 11:1 compression if i remember correctly. When i punch that in i get 337 with the stock flow #'s. I imagine the bone stock flow numbers i have would improve with a 3 angle valve job, as is in the buildup.
With the Comp rail-type rocker arms, would i need to get the guideplates, or could i do without? is .531" valve lift too much movement of the pushrod for the stock pushrod holes? I might try doing a home port job on the heads, but not sure how much that would help since i don't have a flowbench and am not an experienced head porter. Getting bigger valves would probably help too, but it's all gonna add up. I guess i'd rather have a poor performance car that i can drive than having it sit in the shop another summer waiting for more $$. Gotta be sensible about all this. [This message has been edited by Dubz (edited 03-16-2005).]
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