Internally Balanced 360 Cast Crank

[Cudafever]

My buddy had a stock cast crank rod and pistons, turn it over 6000 all the time. told him he was going to bust that cast crank if he keep turning it that much. We raced every week end in the summer for 3 year before he got married. Still has the duster, still has the shaved 360 head chry purple cam, and stock rotating bottom end.
o and it was in his 68 dart GT, that he race before that.

 

[19DUSTER73]

I wouldn't think 6000s to be an issue or even low 7s as long as it's balanced well and not just held there. I hear the bigger issue is oiling at higher r's. A guy should probably be looking at aftermarket forged stuff if you are worried about rpm killing it. Just my 2 cents.

 

[dusterdoug]

So why piss away $300.00 for an internal balance when you don't need it? If you want it internal, buy a forged crank.


BTW, I don't know who is doing your machine work, but they are either double damn good, or he works way too cheap. $300.00 wouldn't get you a balance job with Mallory. It would start at double that, and go up from there and would depend on how long it took, with another $50.00 just because it's such a pain in the *** to do it.

Gee thanks, my life is better because of your knowledge. My reference of $300 wasn't a quote, I was just making a point.

 

[dusterdoug]

I wouldn't think 6000s to be an issue or even low 7s as long as it's balanced well and not just held there. I hear the bigger issue is oiling at higher r's. A guy should probably be looking at aftermarket forged stuff if you are worried about rpm killing it. Just my 2 cents.

The one I may do now will be just a mid 11 second pump gas streeter, 6000 max.

 

[dusterdoug]

But then, will it external balance with KB107s and SCAT I beams? We shall see.

 

[dadodgekid]

I had a .030 360, scat i beams and kb107's with a ported j-head. External balance with no mallory.

 

[70aarcuda]

Basically did the same thing with 71 Duster engine...has Scat 1 beams and Ross flat tops that weight in at 480 grams....externally balanced it....they took alot of metal off the counterbalances...

 

[19DUSTER73]

Yes it will. That's what I ran in my last motor. Scat i beams, Kb107s, external balance stock crank. Port matched j heads with a comp 292h. Went 11.64 at 115 in a stripped down 73' Duster.

 

[dusterdoug]

dont know...never broke a 360 oem crank whether it was internally or externally balanced...sometimes I fell stupid and what to spend money uselessly and internally balance the crank...

my 71 demon and 71 duster are externally balanced...71 dart in internally balanced....also have an internally balanced crank in another engine...this crank is going in a short block to replaced the short block in the 71 dart...hence...already have balancer and flex plate for internally balanced crank.

Back in the 90s was spinning a oem 360 internally balanced crank 7500 rpm...stock rod broke...crank survived...and it had heavy trw domed pistons..

Good stuff, thanks AAR!

 

[ValiantRacing]

I have a 360 stock cast crank and rods, that has been internal balanced, it was done back in the 90s, has kb pistons with J heads, spin it to 6500 , runs 11.30s. Street car

 

[yellow rose]

I have a 360 stock cast crank and rods, that has been internal balanced, it was done back in the 90s, has kb pistons with J heads, spin it to 6500 , runs 11.30s. Street car

View attachment 1715041418

Would it have been slower if you left it externally balanced? Just curious what you think.

 

[dusterdoug]

Thanks all! Clears me up on some external balance fears!

 

[ValiantRacing]

Would it have been slower if you left it externally balanced? Just curious what you think.

I do not really know, i bought the engine from a friend, he had all the work done.

 

[yellow rose]

I do not really know, i bought the engine from a friend, he had all the work done.

Thanks for the reply.

 

[70aarcuda]

Crank with slug...measure 1 inch in diameter...

 

[nm9stheham]

Thanks.... does it go all the way through?