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Help with building 351c dirt track motor

6K views 7 replies 4 participants last post by  GT350HR 
#1 ·
First post and I need help. I'm getting into racing next season and of course the E-mods are primarily chevy powered. Being the Ford guy that I am, I want to use a 351 based motor preferably a Cleveland. But the only issue I see with the rule book for running a cleveland is the max valve size on the intake is 2.02 and the intake valve on a 2v Cleveland head and 73-74 4v heads are 2.06 and having to run a 4412 2 bbl carb. Below are the rules for the engine, looking for suggestions building a Cleveland around these rules that will make power around 7k rpm if possible. Thanks!


Heads - OEM cast iron heads only
- No aluminum or aftermarket heads
- No grinding, porting, or polishing anywhere
- Max Valve size 2.02 intake 1.60 exhaust
- Minimum chamber size 58cc


Valvetrain - Max .480 valve lift, measured at camshaft lift
- Hydraulic Flat Tappet Cam Only Maximum of .004 Valve Lash measured at valve
- must pull 15 inches of vacuum at 1000 rpm
- screw in studs permitted
- rocker rollers permitted; 1.6 to 1 ratio for Ford
- stud girdles are permitted
- shaft rockers not allowed


Rotating Assembly - Max of 175 psi compression per cylinder; race fuel allowed
- Any cast, hypereutectic, or forged piston allowed
- No stroking or destroking, 362 max allowed cubes; 4.060 max bore
- OEM or cast aftermarket crankshaft allowed Ford 3.50 max
- Only stock appearing cranks; no knife-edging or lightened crankshafts
- Minimum crank weight of 52 lbs
- 6'' max I beam rods, cap screw rods permitted
- balancing of engine permitted
Carburetor- Must be Holley 500 CFM 2 bbl 4412
- No grinding or polishing allowed
- Throttle Bore Max is 1 and 11/16''
- Venturi Max is 1 and 3/8''
- One inch spacer plate may be used
 
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#2 ·
min specks for a 2v head in my ford book is a tolerance of 2.03 to 2.06 if the old ford oho book is correct but it mostly specks out the 4v builds.


If it helps in any way I DO HAVE A SET OF TRW open chamber 2v forged pistons .030 over compression is 12.0 or 12.5 to one. Would allow a lot of DURATION AT .050.

sOUNDS TO ME LIKE THEY ARE MIXING UP the W with the C a bit as they state 1.6 ratio rockers stock they were 1.73.

Chevy rules very afraid of 351C motors.
 
#5 ·
#6 ·
are you buying a new block?

do you have to meet wissota rules?

what are you doing for a camshaft?

you need to check the weight of the crank you want before you buy it . i think the callies dragon slayer cranks are under the weight limit

you can use a cleveland main but thats a bit of a pita.
 
#7 ·
The valves in the aussie 2v heads are a bit too big at 2.04 and 1.65

you could probably run a 2.02 or cut the od of a 2.04 down a little but you would probably have to install smaller seats in the exhaust to get the valve size down then blend the seat in if it overhangs into the port.

you also need to have them define the term "no porting" . you can often get a bit more flow by simply cleaning up the bowls and modifying the short turn radius and shaping the valve guide etc, and they may or may not consider this porting.
 
#8 ·
bjohnson,
You need to get a rules clarification for sure. Your post specifies OEM heads which could include the Aussie 302 head , but as has been mentioned , the valves are too big. Another OEM head is the N351. If that head is legal , you have a chance . If neither is legal , you are in trouble as nothing Ford made will match the Chevy , sad but true. If the N351 is legal , the popular combinations are 8.7 deck with 5.85 long rod , or 9.2 deck with 6" rod. I am not sure of the class they run in but there are engines like that running in your area already.
Randy
 
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