Hey guys.I have a 350 with a comp cams 270h cam,edelbrock performer RPM intake,1406 edelbrock carb,dual exhaust,an HEI.


Today I was racing my freind and I had it revved to 5500rpm.



After that I was at autozone talking to a guy about his impala he built.He had a stock bottom end and revved 6 grand and blew it up.He didn't say how.

I wanna know how high can I rev with a cast crank.The motor in my truck now is getting redone soon.I want it to last.



My truck has a 2 bolt main block.Would a 350 with a cast crank some H beam rods,and hypertec pistons would it be alright to rev past 6000.The reason I am asking is my truck has 3:73 gears.At 90mph it is revving 5000.I will probably end up swapping a th350 in it.Which I believe still has a 1:1 3rd gear ratio.

The new motor will be like this.


355,hypertec pistons,9.5:1 compression,Comp cams 280h cam,comp cams lifter,timing chain set,Edelbrock performer RPM,Edelbrock 1406 carb,hedman 1 5/8 headers.I am not sure on the casint # of the heads.I know they will get 1:94/1.60 valves with just gasket matching on the ports.

This truck is my daily driver so I can't get to radical.I am building a nasty 406 to get mean with.

 

dude when you find out let me know,ive got a 92 tbi 350 with a th350 with 3:73's in it basically stock motor, but like you I have to get the rpms up to try and keep up with traffic, at 5000 im only goin 80

 

almost 100% of the time your engine will stop moving air and making power before you reach the mechanical limits of the parts in it. alot also depends on if the crank was blue printed or simply installed to "spec".

 

I have a stock bottom end L98. The motor has never been out of the car. I take it to 6500+ all the time. 2 things of importance here ...

1) Make sure your valvetrain can handle it.
2) Run a good aftermarket harmonic balancer that is efficient in the upper RPMs.

Tim

 

I guess what I was trying to ask is.


What is the ussually fails first.The crank,rods,main caps,pistons,etc,etc.


I have been really messing with motors for a few months now.I have been interested in them all my life.Until I got my trucks I had little hands on experince.


I am probably going to be going with a 700r4 in my truck soon.So I hopefully will not have to worry to much about the engine at highway speeds.


What do you guys consider revving high?

 

Well, the factory redline for a stock L69 (305 HO) was 6000 rpms...

 

the limit before damaging harmonics occur is 6034 rpms for a cast crank

i spun a bearing overreving it

 

What size of tire are you running? A 25 inch tall tire will put you at 99. something mph at 5000 rpms. I think your tach may be wrong.

 

What size tire are you running? A 25 inch tire will get you right about 100 mph at 5000 rpms with 3.73's. Check your tach.

 

hooked up to a scanner at 5000ish rpm's im showing to be going 83mph new manual speedo to, tires are 245/50-16

 

stock rod bolts go first