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  #1  
Old 11-28-2000, 02:11 AM
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daren44 daren44 is offline
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I am getting ready to build up a 360 for a street stock class. I've cut my teeth in the bombers last year, and have never driven in this next higher class. The track is a 3/8 mile paved oval, semi banked. One of my questions is what cam to use. My rules require flat top pistons, no decking below piston height, cast heads and intake, headers, cam lift .450. I've had some advice on a cam with .447 lift, 225 to 230 duration. Any suggestions from someone who's actually got a mopar under similar circumstances? Also, what brand(s)? Are the swirl port heads worth the difference over the x or j heads? What gear should I run. Currently have 3.91, running in 2nd gear. I estimate this will put me at around 5800 - 6000 rpm's. Should I go for a higher (less rpm's) gear, given the limited cam rule? Thanks.
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Old 11-28-2000, 04:13 AM
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9dodge 9dodge is offline
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I'm in the same boat you are as far as rules are concerned.
I have to run a 318, but limits are real close.
If you are running the same track every week, I would build a torque motor and gear the car to the motor and kill'em every week.
Let the Ford and Chevy guys twist the crap out of there motors. My 318 makes 352 ftlbs at 3000 rpm and doesn't go below 300 ft lbs until 5600. Torque wins at the track.
The late model heads you need are "308"'s or if you can find a set of "x" heads. Alittle bit bigger valve, if allowed , would be a good addition. I can't help you on the cam choice, but I'm sure some one will speak up.
Remember, it is not all horse power, he who puts the most power to the ground the longest will win the race.

Michael
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  #3  
Old 11-29-2000, 12:26 AM
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cageman cageman is offline
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I race at a 3/8 dirt and I run 3.91 gears also, with an 82 inch tire. I have a 904 and the final gear in second is 6.03. I know the chevy guys like to run around 6.00 to 6.20 gears but they seem to turn more rpms. I am building the same motor but 202 160 J heads are what Im using with a max cam of 455 lift and two barrel carb. I ran the 340 six pack cam and it was around 455 lift and it made good power. This winter Iam going to try running cooling lines from the back of the intake into the thermo housing. I guess this will run way cooler and get rid of some hot spots in the motor. I saw it on a wissota super stock with a 360 that ran about 14 to 1 comp and his only problem was finding good enough gas for it. I know that 360's are tempermental when they run that much comp but the cooling tip seemed to work for him.
What plug should I use in a 360 race combo. Start cold and work up or does someone know what plug to use (champion)RN??YC
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Old 11-29-2000, 12:43 AM
340king 340king is offline
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Typically, we try to match the cam to the compression. This allows us to achieve optimum efficiency in the desired rpm range. More compression (static) provides more dynamic compression when the engine is spinning. This allows us to open the valves for longer periods of time (duration) and not give up the required dynamic compression.

In other words, a 9.0:1 can run say up to 245° dur @ .050", a 10.0:1 can run say up to 252° dur @ .050" and a 11.0:1 can run say up to 258° dur @ .050". The higher static compression yields more dynamic compression to use. Compression is key to getting the cam to work at higher rpm. It allows the correct valve timing for high rpm engines.

I hope that I have not covered this in too much detail or in too basic a level. This is one of the fundamental building blocks for performance engines.

So to answer your question, match the cam to the compression you plan to run. This may be a challenge with the lift limit. One trick may be to try and get some lower (ratio) lift rockers. This would allow a more normal grind and not violate the lift ru
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Old 11-29-2000, 12:58 AM
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cageman cageman is offline
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Like what a 1.6 rocker or something?
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  #6  
Old 11-29-2000, 02:29 PM
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daren44 daren44 is offline
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What compression do you guys run? How much difference does it make? I'm limited to flat tops and decking to piston height only. I figure this would put me around 10:1 or slightly less? Should I go for all I can get and run racing gas or go for a little better than 9:1 and run pump gas (cheaper)? Also, what 4 barrel carbs are you running on a 360? Has to be a production carb in my case.
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Old 12-04-2000, 05:28 AM
340king 340king is offline
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Sorry it took so long to get back to you. I was building a sub woofer for a home theater system last week and I had several evening meetings.

What I was getting at with the rockers was to find some rockers that had an actual ratio of 1.3:1 or so. That way you could purchase a cam that would yield higher lift with 1.5:1 rockers and still meet the .450" lift rule. This might make cam selection that much easier.

As for carburetors, there were some 4 bbl Holleys used on production 440's if my info is correct. They were 650 cfm with vacuum secondaries. Otherwise, a good AFB or maybe an AVS might work. The carb I use is a highly modified Holley double pumper.

As for compression, that is another question. It kinda depends on the track, tires, banking angle, etc. Finding the right engine combination can take several attempts. This is not unique to Mopar. Most bowtie guys have gone through the same thing. Their only advantage is that they have so many parts to choose from and have hundreds of people experimenting with different combinations. If you look at all the variables that can be changed, it could take years to find one that comes close to what you want.

I use two computer programs to try and find what I want from my engines. This is a quicker way to try many different combinations and see how they stack up against others that have been tried. This cuts down the R&D time, but it doesn't eliminate it. One of the problems is knowing what you want for a torque or HP curve. More is not always better. Where it is at and how it comes on is sometimes more important.

Changing compression changes many aspects of the car including the handling. Another thing to consider is the cost of both the purchase price for the higher compression parts and the increased wear and tear on equipment. With these in mind I would try and use a good flat top piston that has enough, but not too much valve relief for your cam lift. The KB's come to mind, but they have huge valve reliefs and may give up some compression. I don't know if Speed Pro makes hyper-eutectic pistons for Mopar applications. If so they might have something with a little less valve relief.

In your case, I would try and mill the heads as much as possible to approximate the closed chamber style (remebering that the decks are not real thick and thinner head decks can cause head gasket failure). This will increase the compression and quench of the cylinder, upping the output with both. If you can get to 11:1 it may be worth while. This is not so extreme that you need to order a lot of special parts to run it. Two things you will need to do. First, run a good gas, VP red or C11 will both suffice in my opinion. Second, I would run the Felpro race head gaskets. They are a cheap insurance against a blown gasket. I re-torque mine after cam breakin.
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  #8  
Old 12-05-2000, 04:00 PM
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MOPARVANN MOPARVANN is offline
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Sounds like your rules are similiar to mine, flat top piston and production carb. I am currently running a 360 block .040 over with standard low compression 340 pistons=11.5:1 on top of this J or X heads work well. The carb I am limited to is a 600 Holley or the stock carb. I went with MOPAR parts throughout this car and again choose the old original plastic carb, because it run well and I already had it(my reply to the tech man)this THEROMQUAD has many advantages:
1)it comes on quick to get out of the turns
2)it flows 850 cfm (vs 600 on the holley)
3)it runs cooler
MOPAR PERFORMANCE has done several articles on these carbs and the few modifications needed are very easy.GOOD LUCK and keep the MOPARS out front.

------------------
MOPARVANN---C & V Racing-Middle Georgia Mopar Club

[This message has been edited by MOPARVANN (edited December 05, 2000).]
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  #9  
Old 12-11-2000, 04:09 AM
AVENGER29 AVENGER29 is offline
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seems like no one is addressing oiling concern,so here is my 2 cents worth.cant help you with carburator or cam,run out of control hobby stock on methanol.we routinely turn our 360 past 7,000 rpm.
360's have a concern with #3 rod bearing oiling, if you're going to turn this engine at or above 6,000 you need to spent some time on the oiling system. stock car specific oil pan are expensive,recommend you use a rear sump truck pan and use speedway pan kit to modified,fairly inexpensive,but will take some time,you will also need to fabricate a pick up,we use the stock pick up with 3/4 steel tubing.oh once you figure out positioning weld it.use fully grooved main bearings,if you have a hard time finding them,get 2 sets and use only the grooved bearings. highly recommend using melling high volume pump only,we also install hemi spring,need to spent some time and re-worked rear main cap,we increase size and port match,spent some time in the galleries,make sure their clean,relieve them if neccessary. enlarge cam bearing oiling holes slighlty & make sure their in the right place.you need to drill a 3/32 diameter hole with a chamfer in the top of the rod.we also fabricate a fitting on the rear of the right valve cover & the left side on the oil pan,we run a 3/4 hose from one to the other to evacuate oil from the valve cover. for what its worth we have a pile of 360's with portions of the blocks missing because we didnt know....luke
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