MY 350 Let Go At Around 6000/6300 RPM

[Pardue'sCustoms]

it broke a rocker bolt and bend the push rod. i pulled it today and tore it down and this is what i got
the block is 3970010
the heads are 3932441
and the crank is 3932442
and center caps are 3412



what mortec is say about the crank

3932442..267,305,350..cast...medium journal...3.48" stroke



and the block
3970010....302.....69....4...Z-28 Camaro
3970010....327.....69....2...Trucks and industrial
3970010....350...69-80...2 or 4

and the heads
3932441....69-70...350..........76cc chambers

suffix code on block
1974 TMM 350 conv.cab 145 2 C-10 & 1500
1980 TMM 350 conv. cab, a/t, Cal M LT9 170 4 C-20 to 3500

[cdowns]

that what normally happens when you take an engine with a 5500redline and overrev it thats why they call it a REDLINE

[dat]

What the heck were you doing up at 6000????

[bigjimzlll]

yea..if you want to turn a sbc like that it takes some long green...valve float with weak springs and a hydrolic cam will eat an engine up real quick...did you do any real damage(block)?

[Pardue'sCustoms]

no iam going to put roller rocker back on it and put some 7/16 screw in stud and try it again . the motor has been bulit but who ever bulit it took cheap way out on rocker they bought long slot rocker but the orig kind and i am going back with jegs rollers

[bigjimzlll]

invest in some good springs too

[72CustomCamper]

What was the age (mileage) of that engine?

I routinely wound up my AMC 360 (Jeep) to about 6800-7000 and it never blew...

[Liz]

Tony didn't you have this posted on the 73+ board before? I went to show HC the pic and it was gone ...................
Isn''t this the truck you just bought a few weeks ago????

[mikep]

Heres what probably happened. You over revved it past the point that your springs were designed for. You went into valve float and your piston hit the valve which then tranfered its enrgy into the rocker which in turn broke the stud and bent the push rod . Theres nothing wrong with stamped rockers and they wont prevent that from happening again. You have what looks like a stock engine. Don't try to rev it that high. Maybe you have a cam too big for the rest of the motor. That doesnt make it a "built" engine. It Only makes it a time bomb. No you have to look at a few things. Did the lifter launch out of its bore. If it did you lost oil pressure and may have done other damage. If not you got lucky but you will have to check the condition of the pushrod guide slot. If it got deformed then your'e screwed . It'll break pushrods as fast as you can replace them . If it didnt get deformed then your lucky again and count your blessings on your way to pick up a set of valve springs that will handle that sort of RPM. If it did get deformed then waste no time and pull the heads off to take them to the machine shop for a set of screw in studs to be machined in. That will allow you to inspect the tops of your pistons for valve damage and your valves for damage as well. You could probably get by with self alligning rockers like come on late model chevies as they dont use the alignmnet slots like the old engines do,.

[big_ac2001]

we used to run stock 350's up to about 6,100 rpm in our dirt track cars. ran stock valve springs. never had a problem.

[mikep]

A stock engine with a bigger cam has a steeper opening ramp will open the valves faster and will float the valves at a lower rpm than a stock cam will . You'll build more power with the bigger cam but bigger cams do float the valves in situations that a stock cam would not. That is unless you are using the right springs.