Box Stock

Modified Class Predator Build

C

cubicinches

New member
I'm considering building an engine for the modified class at a track, the rules are as follows:

MOD LIGHT 350 lb.
212cc Clone Engine Max
Stock head
Stock valve size
Stock piston
Stock crankshaft & stroke
.231 Max lift camshaft
Any single valve spring
+.020 Length billet rod OK
.000 Deck to piston clearance
Aftermarket exhaust OK
Aluminum flywheel OK
Gas or Methanol OK
Stock appearing clone carburetor (No Carb Spacers)
Any Clutch
No internal machine work

Here's the list of parts I've compiled from, tell me what you think, and if these parts will even work together well or at all. This will be the first clone I've built.

DJ-1175 GX200/Clone Cooling Fan
DJ-1175 DJ-1175 GX200/Clone Cooling Fan $3.00

6602-P ARC Predator 6.5 Ultra-light Flywheel
6602-P 6602-P ARC Predator 6.5 Ultra-light Flywheel $100.00

DJ-1109IP Predator CL-1 Improved
DJ-1109IP DJ-1109IP Predator CL-1 Improved $36.00

DJ-1345 BSP Carb Stud
DJ-1345 DJ-1345 BSP Carb Stud $1.55

18-930HJ 3-Staged J-Pipe Header
18-930HJ 18-930HJ 3-Staged J-Pipe Header $33.60

6926 Air Filter Adapter Clone/GX200
6926 6926 Air Filter Adapter Clone/GX200 $13.95

DJ-1415 Chain Guard / Heat Shield
DJ-1415 DJ-1415 Chain Guard / Heat Shield $12.50

DJ-1146 Top Plate w/ Walbro Pump
DJ-1146-FPC1-1 DJ-1146w/pump $34.00

6877 Pulse Inlet Fitting
6877 6877 Pulse Inlet Fitting $2.00

FR-25-00 Hi-Quality 2.5 QT Fuel Tank
FR-25-00 FR-25-00 Hi-Quality 2.5 QT Fuel Tank $33.75

DJ-1056 Valve Spring 26lb HP 'White Stripe'
DJ-1056 DJ-1056 Valve Spring 26lb HP 'White Stripe' $10.00 (2 @ 5.00 ea)

ARC Racing ESTIMATED TOTAL $294.35

I left off a billet rod because I'm not sure I would even need it for just a modified class, and it's not going to gain me anything but durability. If you think otherwise, I could pony up the extra money for that, I'm just trying to do this on a budget. Also, if there's a better part of similar price or a cheaper part that I could/should use, let me know. I'm totally open and willing to learn.
 
If going that route, get a ARC 6619 flywheel, a ARC S/A carb, and a Mod2 cam, 1.3 stamped rocker on intake only. ARC billet rod for the extra$ for sure. The rest is good.
Scratch the ultralight flywheel, fan and cl1.
With this combo you will have fun!!!
 
What lift is that Mod2 cam? I don't think it was listed on the website. Also why not the ultralight flywheel? I'm just curious.
 
The ultralight flywheel is better suited for a wild build.
The 6619 is better suited for your kind of build, a little weight goes a long way.
The Mod2 is listed under the predetor and clone.
It is stock lift but a good kick in duration.
 
Re-check the .231 'max' cam lift! Also, 26lb Springs will 'slow-u-down', run 10.8 0r 18 lb (at most) w/stock rod at less than 6500rpm...JMO
 
sCREamnClones said:
Re-check the .231 'max' cam lift! Also, 26lb Springs will 'slow-u-down', run 10.8 0r 18 lb (at most) w/stock rod at less than 6500rpm...JMO
Click to expand...

So lighter springs? I just assumed bigger is better to maybe get more rpm's. I by no means know that, I just assumed. Could you explain why the stiffer springs would be worse than lighter ones with a billet rod? If it's for engine life with a stock rod I understand, but if a billet rod is needed for higher rpm's and better performance I'd gladly add it.
 
Add the billet rod and 26 lbs springs...he meant that with a stock rod do not go over 6500rpms. So higher pressure springs would not be necessary.
A mod2 will make power to 7500rpms plus...
I miss read the original post...where will they measure the lift of the cam?
Because if ya use a 1.3 rocker on the intake only you would be over the max lift allowed.
 
I'm not sure where/if they would even measure it to be honest. It's not a sanctioned track, and there's a $150 cost to protest, so I'd definitely be willing to fudge a little and take my chances on that. Lol if you ain't cheating you ain't trying.
 
In that case then get that 1.3 rocker arm on the intake of the Mod2 and let her rev...good bottom end with a good pipe to let her breath on the top end...
 
also for 24 more $$ you could get a black mamba jr cam from smallenginecams.com and get a pair of 26lb springs and some great oil jmo
 
cubicinches said:
I'm not sure where/if they would even measure it to be honest. It's not a sanctioned track, and there's a $150 cost to protest, so I'd definitely be willing to fudge a little and take my chances on that. Lol if you ain't cheating you ain't trying.
Click to expand...

If you are cheating you "ain't" winning. You are cheating.
The challenge is build within the rules and making it work.

Tom
 
TEAM580 said:
If you are cheating you "ain't" winning. You are cheating.
The challenge is build within the rules and making it work.

Tom
Click to expand...

I think you're missing what I'm saying here. They didn't specify in the rules where they check the lift, and by reading the rules it specifies camshaft lift only anyway. So if you don't fudge the rules when they don't specify a certain criteria, you aren't trying. I.E. working within the rules and making it work. Until someone tells you what you're doing is illegal due to a teardown or otherwise, you might as well do it, because for all you know, everyone else is doing it too.
 
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