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Author Topic:   rebuild or not?
Racer98
Dirt Full Roller

Total posts: 40
posted March 07, 2003 11:44 PM
Hello, I am racing in a hobby stock class. I get 6500 -7000 rmps. I have a stock 350 for a back up, but wonder if a stock 350 will be able to handle that many rpms. Its at back up, but I want it to be a good one, with minimal money, what would you do with it if anything, thanks

KPLugnut
Dirt Freak

Total posts: 408
posted March 08, 2003 06:04 AM
Any totally stock motor will not turn rpms like that because (among many other things) the valve springs are far too weak to handle it.
The valvetrain in general will not do that.
A stock cam will make no power above about 4000rpm either.
Best things to do are good rod bolts, the right cam, valve springs, beef up the rockers if possible, get rid of the stock timing chain and gears, and at the very least, a new oil pump.
Outside of a "real" complete rebuild, I don't think you could get any appreciable power or rpm gains without doing any less than that.
Then there's the carb, intake, and head combo....but that's a whole other ball o' wax.

Hope that helps,
KPLugnut

flanndad#17
Dirt Full Roller

Total posts: 28
posted March 08, 2003 10:40 AM
You said it's a back-up, so if you plan on running it just a week or two to get point's.
I think you have a few options.
1) don't spend much, save it for the real motor.
2) good oil pump - cheap insurance
3) cam & lifters
4) Heads maybe take a choice and hope you don't wreck them on the good motor or get some of the same kind as your good motor and have the bare casting's ready.
5) just have close to the same stuff ready and work your **** off during the week to use the two to make one.

racer17j
Dirt Forum Champ
Total posts: 1565
posted March 09, 2003 07:05 PM UIN: 54865418
all i ever run is stock junk yard motors i just put a re ring kit in them cam'valve springs,oil pump and double roller timing chain, and haven't in the past but am going to arp bolts this year i have less than 300 in my motor and will run it all year long but 6500 is the max i will turn it tho

sjakes8
Dirt Roller

Total posts: 7
posted March 10, 2003 07:15 AM
quote:
Originally posted by racer17j:
all i ever run is stock junk yard motors i just put a re ring kit in them cam'valve springs,oil pump and double roller timing chain, and haven't in the past but am going to arp bolts this year i have less than 300 in my motor and will run it all year long but 6500 is the max i will turn it tho

With that being said Racer17J, what class do you run, and what do you do with heads? I run a Hobby class, and you hear all kinds of things that guys run but only way you find out is when someone claims and checks out the motors.


4b316
Dirt Full Roller

Total posts: 45
posted March 10, 2003 07:49 AM
I agree with lugnut if that,s the rpm you want to run.You could run the stock springs if you was going to keep under 6500 but you said you would turn it 7 so put good springs in it to be safe

racer17j
Dirt Forum Champ
Total posts: 1565
posted March 10, 2003 10:29 AM UIN: 54865418
the class i run is called econo stocks suposed to be a knock the windows out and put in saftey stuff class we run 360 cid and 9:1 compression.i just freshen the heads up with a set of z-28 springs, seals, and 1.6 long slot rockers. funny you should mention the claim deal we had a guy realy mad one nite after he claimed us and we exchanged one of our std bore dish top re ring kit and cam junkers for his forged 30 over with 487x heads on it lol needless to say we haven't been claimed since

sjakes
Dirt Roller

Total posts: 14
posted March 10, 2003 11:31 AM
that is too funny!!! At our track once claiming starts, obviously it goes all year long, and it usually starts within a week or two of the start of the season.

It wouldn't be a bad rule, but majority of claims are grudge claims that have nothing to do with motor issues.


superdave
Dirt Forum Racer

Total posts: 89
posted March 10, 2003 05:44 PM
I get to see eveyone's engine at Salina and many times I look at a car and think "this stuff will never win a race". But it does. Small carb, low HP heads, wrong intake. Stuff I would give away makes the top four often and wins every now and then. I am always amazed.

With a heavy flywheel or full converter the engine is less likely to pull a rod or piston apart because that extra weight doesn't let the motor slow down as quickly.

Compression test and air up the cylinders with the rockers off will tell you where the leaks are without taking the motor apart. Take off the intake and exhaust and spray a little watered down dish soap in the intake and exhaust and look for bubbles.

Valve springs, timing chain, cam, lifters, re-ring kit,polish crank and resize rods. If the rods have never be apart then you can use them again. If it's been rebuilt then buy new rod bolts. Shim the oil pump spring. If the pump hasn't failed yet it probably won't.

Carry your claim money and claim the should be claimed.

Good luck,

------------------
Superdave
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