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Discussion Starter · #1 ·
hi everyone,
i have been looking through this forum for several months now and i have a few questions for you guys. Let me start by saying i know nothing about nothing except, what i have read on the internet. i am getting a circle track dirt modified hopefully within the next year and i am wanting to run a 351w dont have any other reason then just want something different from everyone else out there in the b mod class. I am going to start getting the engine parts compiled now so it doesn't cost me a huge chunk when the time comes to build it. I want to use as many stock parts as i can if that is possible the only thing that i know i want, or i think i want is to spin it around 65 to 7000 rpm's and i would like for it to not blow on me but doesn't everyone. I think i am going to use the n351 heads and past that i'm stumped i will post a link to the rules that i have to stay within and hopefully you guys will understand what i can't and can do within reason not looking to have the biggest and baddest just something that will get me around the track as cheap as possible and still stay in atleast the middle of the pack and if anyone has ever built something like i am wanting before then please send me the formula thanks in advance everyone
here' the link
http://valleyspeedway.com/Documents/2012 Valley B Mod Rules.pdf
 

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What is your location? Our engine builder here has built several of these engines and have won many races. He is a Ford expert. What sanction is this, sounds a lot like IMCA Northern Sport Mod rules. I am an IMCA tech at my local track lol.
 

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You can't run those Yates heads. Has to be cast iron, OEM production, inline valves only. You can't even run a Clevor, Cleveland or Boss type engine because those heads have canted valves. If they let the Clevelands and Boss 351's in there it would be Chevrolet's to the rear.

Those are some anti-Ford, pro-Chevrolet rules you have. I've seen rule mandering a lot over here where I live. The only heads with some promise for your set up would be cast iron GT 40 heads such as they installed on the early lightening's and cobra's before going to aluminum.

Meanwhile, the Chevy guys can run the 327 375 horse or 350 350 horse production cast iron heads. Doesn't quite seem fair.
 

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Discussion Starter · #5 ·
Yes the n351 heads are cast iron and I am located in kcmo will be running a vallyspeedway I can use all the info you guys can give and my next option will be the gt40's
 

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10* valve angle and improved valve centerlines is a big performance advantage with those N351 heads. Get the valve train set up right and you would have a cylinder head that could perform better thant he bench flow numbers indicate.
 

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I don't know of any production Ford product that has had the N351's from the factory so I could be wrong. The N351 heads were designed by Ford Racing with some influence by Robert Yates so I just call them the "Yates" heads. Rules say production, OEM, cast iron, can't port or polish them either or "ANY ALTERATIONS". I still think you are stuck with iron GT40's. I read all your class rules you posted in that link. There is a lot of stuff in there. Can't run a roller cam or stud girdle. Limited to a Holley 500 cfm carb. Roller TIP only rocker arms, no full needle bearing rockers. Have to run Edelbrock Performer intake. Flat top or dish pistons only. Did you all read the rules?

I didn't say this but I do know of left turn dirt guys putting acid in their heads to etch away some of the metal. It still leaves an as cast look to them. It is illegal strictly according to the rules but you'd have to flow test the heads to know this was done. There is a lots of cheating that goes on in the dirt, LOL.
 

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Discussion Starter · #10 ·
Yes thank you for reading them I don't know enoughf to understand everything like you guys do and nobody around here knows that much about the fords I talked to ford teck guy yestarday and you said those heads should qualify as production heads but I don't really know I open to all info you guys can provide also if anyone has any engine combos or know someone who might please let me know whether or not is is with the 351's or the gt40's
 

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Discussion Starter · #11 · (Edited)
ok guys found this stuff i am reading everything i can i just cant see any clairity at all. once again i dont know that much to begin with but take a look at this and let me know what you think if thier is anything that clairifies i cant use them

The N351 Sportsman cylinder head has been retooled and is now in stock and ready to ship. Designed for Ford 351W engines. Ford N-heads were developed by Ford Racing with the help of Robert Yates.
910-14351 Instructions (PDF)
Approved for NASCAR Late Model Stock Cars, IMCA (Stock Car and Modified Division), WISSOTA, DIRT, UARA, and most other stock car sanctioning groups. Please note to check with your specific sanctioning rules for confirmation of applicability.
Machined for 2.02" intake and 1.60" exhaust valves
Intake and exhaust valves have been moved .070" to unshroud the intake valve
Valve angle changed from 20 degrees to 10 degrees to further improve air flow
Three-angle valve job
Intake port volume 200cc
Exhaust port volume 82cc
Extra thick deck surface
Webbed rocker bosses for improved strength
Compatible with stock and Ford Racing intakes
Use .708" reach taper seat spark plugs


Assembled heads ADD:
  • Stainless intake and exhaust valves, 5.140" length
  • Heat treated 7° steel valve locks, 11/32"
  • 7/16" rocker arm studs, 1.850" mounted length
  • Stepped guide plates
  • Speedway Racing Dual Valve Springs
    • 1.465" O.D.
    • .800" I.D.
    • Installed Height: 1.875"
    • Seat Pressure: 120# @ 1.875"
    • Open Pressure: 394# @ 1.175"
    • Solid Height: 1.080"
  • Steel 7° spring retainers, 11/32" stem
    1. Requires roller rocker arms with offset intake valve pushrod cup.
    2. Unique header flange required.
    3. Check head bolt length, may require non-stock length head bolt.
my rules not much on the fords



[FONT=Verdana,Bold]
13.) HEADS
$400 protest clause applies on head removal For clarification purposes: (Heads cannot be surfaced under 70cc)



EQ IMCA stamped sport mod ch350I heads are allowed with legal valve size.
]For casting numbers see below
GM

OEM Cast cylinder heads only. Maximum 2.02 inch intake valves and 1.60 inch exhaust

valves. Rocker studs may be pinned or non shouldered screw in type or shouldered screw in type.Stamped steel roller tip rockers arms ONLY!!!! Poly locks allowed. No stud girdles allowed.


Guide plates are allowed.

NO PORTING, POLISHING OR ANY ALTERATIONS ALLOWED!!!!
GM
3986336, 3986339, 3986339x, 3986388, 3932441, 3973487, 3973487x, 3973493,

3951598, 468642, 333882, 3998920, 3998991, 3998993, 3998997

FORD

Any cast iron OEM production head with inline valves. No SVO heads allowed. NO

CANTED VALVES!! Guide Plates Allowed

Maximum 2.04 inch intake valve and 1.70 inch

exhaust valve. No aftermarket heads. Non shouldered or shouldered rocker studs allowed.
No stud girdles allowed. Stamped steel roller tip rocker arms ONLY!!! Poly locks allowed. NO
PORTING, POLISHING OR ANY ALTERATIONS ALLOWED!!!!

[/FONT]

 

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I would get a clarification from your track on the Yates heads. Never hurts to ask. NLMS allows them but they also allow the Brodix aluminum heads. SVO became Ford Racing by the way but it still would not hurt to check into it.

Actually, I think SVO became Ford Racing on the parts side and SVT on the design side.
 

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Discussion Starter · #13 ·
ok, i talked to the track teck last night and, he said that the heads have to be 4 things, cast iron, inline valves, ford part number, and 70cc combustion chamber, im good on 3 of the 4 because they are 64cc combustion chamber. but i talked to the head service company today here in town and the guy thought he might be able to get them to 70cc. can anyone tell me what that will do to my performance what type of compression i could get? i have to use a flat top piston and, i will probably run the heads no matter what. the teck guy admitted he knew nothing about fords not only that but, i looked up the combustion chamber on the gt40's and, they were 67cc's i think. so technicaly i would be screwed there to doese anyone have some good engine combo's for me. keep in mind i do have rules i can't break them all lol. but i technicaly do feel that i will be breaking them because i saw nowhere in the rules that they have to be atleast 70cc combustion chambers but then again, it could be there.
ok i'm here waiting to soke up the knowledge bring it on i have pen and paper ready
 

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This rule is no doubt where the 70 cc thing comes from.
For clarification purposes: (Heads cannot be surfaced under 70cc)

I don't find anything in your rules about decking the block so you can make up a slightly larger chamber with piston/deck clearance.

Those N351 heads apparently require different rockers and special headers from what I have read so you are going to have some expense there.

You need to find a machine shop that builds left turn engines and talk to them. My machine shop does a lot of circle track stuff because it is really big down here. It is not the same as building a drag engine.

 

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Discussion Starter · #15 ·
i thought that was prob the rule but wasnt sure
thanks for sticking with me here on this posting hothod . i know everyone says the 69-74 blocks are the best.why is that?in it the nickle content like gm's blocks or is it just that they are a little more meatier any suggestions on my engine combo?
 

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i thought that was prob the rule but wasnt sure
thanks for sticking with me here on this posting hothod . i know everyone says the 69-74 blocks are the best.why is that?in it the nickle content like gm's blocks or is it just that they are a little more meatier any suggestions on my engine combo?
No nickel in any Ford OEM (production) blocks

.

getting the N head to 70 cc shouldnt be hard ,, do to the shape of the chamber.

bad news is you can't use the head . rocker rule takes them off the list .
 

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I thought I read that the rules also said flat tappet cams only and no hydraulic. That means solid flat tappet cams if I remember that correctly.

14.) PISTONS & CAMS- Flat top or dished pistons ONLY!!!!! Must use flat tappet cam and lifters. No mushroom or roller lifters allowed. No Roller or hydraulic cams allowed. CANNOT ALTER LIFTER BORES. May use oil restrictors.

You might consider investing in this. I have a couple of Tom Monroe's books and they have been helpful to me.
How to Build Small-Block Ford Racing Engines: Drag, Circle Track, Road, Off-Road & Boat Racing
 
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