how high will a 273 rev.

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bill paynter

67 Cuda
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I purchased and installed tach this weekend, took the car out for a spin reved it to 6,000
is 6,000 a safe number for a stock 273
 
Bill, I think 6000 is a reasonable top end RPM for a stock-ish small block. A lot depends on your valve springs, cam, intake, and ignition systems. If you're running old stock valve springs, then you may be getting into valve float or coil bind by then. You can usually tell when the power starts to flatten out that you've reached the maximum limit of one of the above mentioned parts.
 
I've done it on-off without problems (new rebuild). But not that often :shaking2:
 
My 273 had an aftermarket cam & valve springs. I used 6000 rpm for a red line but accidentally took it to 7000 + one time with no ill effects. (I was lookin' to see how close the guy I was racing was & when I looked back at the tach she was hittin' 7000. :tongue3: )
 
sounds like I'm in the ball park
thanks for your input
stock 273 , solid 509 / 292 Cam / heavy springs /391 gear
 
:pirat: Well my 2 cents, on a side note: I put $6000 in a 273 back in the day... 1979 and my redline was 8500 and it bounced off of 9300 a few times with missed shifts with the 4 gear.. Obviously not stock ...

But out of the box if it is a solid bottom end many 273's are fine even with cast pistons to 6000, above that man be carefull! Rod bolts are weak link as are the cast pistons.

OH and at that RPM you can get into lack of oil in the pan too!

:coffee2:
 
I asked that question 25 years ago and A friend who races Mopars and rebuilds his 6 engines almost weekly.... he answered me like this.... " while you are beating the snot out of your stock "grocery getter" motor racing some nova or mustang from light to light....keep a close eye on your tachometer......when you hear sounds like several large iron parts are being dumped onto concrete remember what your tachomoter was reading just before the noise....THAT is how many revs it takes to get to the center of a toosie POP " His point being.....that number is different for every build of every motor, even same motors assembled only hours apart will have different "Flash Points" stay within reason and enjoy long engine life.....push it to the wall every time and you might get 20 runs you might get 1......luck of the draw.....if you are legit racing and have backing ( like he did) he went balls to the wall at the green and never got out of it till he passed the gates....if you are only on the street and you are reving 6k and letting go......you have a whole different set of issues LMAO!!!!! good luck and be a lil bit safe....I absolutly hate seeing a "they dont make those anymore" crumbled into a ball on the hook heading for the scrap heap because some one forgot that lil old ladies still pull out in front of you...they cant see it is a classic that is haulinA$$ they just know they need to get to the bank to deposit their SS checks LOLOLOL!!
 
Yep good point, but I just retired my 273 that was built in 78-79, had 1000s of 1/4 runs, did over 1000 miles on the Ontario motor speedway, major street racing, blew up 18 4sdp clutchs, 2 8 3/4 rear ends, broke 4 drive shafts, and destroyed partially 2 727 trannny's. Never broke the engine!

But as I said, I put 6k in it back when an engine could be put toghter for less than a grand. I even fired the ol 273 up 3 weeks ago before I pulled it out just to shed a tear and hear it roar one more time. :love4:


But yep now I am doing a lrger stroker, will never see past 6200 and should be a steetable combo and not have to live in the danger one.

It is like a Harley Vs a Crotch rocket. I have owned both, they both have a purpose and the less revs means longer life for less $$$ in the long run.

Anyway the 273 is a decent little more as are all LA blocks. The 360 and now these strokers are more torque designed, yes they can be made to rev too, but the longer the stroke the faster the piston speed etc...

oh baby!
 
FWIW, Steve Dulcich wrote an article in the winter edition of Engine Masters on a 400hp+ build up of a 318. In the aformentioned article, Mr. Dulcich states that the 318 is good for 6500 rpm with stock rods, aftermarket rod bolts, stock valve train with the exception of aftermarket springs and a cast crank.

This is assuming that the valve train and all other clearances are set up correctly and this is not a tired old engine with 200,000 miles on the crank. Steve Dulcich has built more small block Mopars than I've even seen, so I would trust his judgement implicitly.

I have not personaly rapped a 273 up, but I have run a 360 Mopar, 302, 400M, and 351 Cleveland Fords up to 6000+ R's with stock rods, ARP rod bolts and cast cranks without any ill effects. But then again, I built these engines myself.
 
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