512 Stroker Dyno time

[comet_666]

I believe the heads are part #60189
It is a blast to drive for sure, i can spin the tires at 50mph which is not necessarily a good thing lol

[Challenger340]

21203 Eagle Kit is 4.375" Stroke for 520 Cubic Inch ?   

[comet_666]

yessir, I think it used to say 512-520

[Challenger340]

yessir, I think it used to say 512-520

It probably did ?
and no matter, my only purpose noting was that the 4.375" Stroker Cranks can sometimes be a bit tougher to clearance the Block for over by the Oil Pickup Boss ? than the more popular 4.250" 512 Stroker Cranks.

Nice Engine 512/520 nonetheless, good job 

[comet_666]

I believe the link to their site used to say 512-520, Looks like they corrected it, I actually think I have a screen capture of web page when it said 512-520
i'm pretty sure its a 520, my builder did not have issues clearance for pickup. As a matter if fact he wanted to get the biggest kit available as it was the same price.

And thank you for the complement, it really is fun to drive.

[chapel40]

What is your cut off for rpm? are you running it to 6k? More? just wondering if it gets valve float up high. I am building my engine similar to yours with a little bigger hyd. cam and wonder if I am making a mistake. Probably should have used your cam. My cam is spect. at a couple hundred rpm higher than yours.

[chapel40]

Have you brought it to the track or timed it?

[comet_666]

I think the highest I got it was to 5800 RPM on expressway actually last week. I punched it at 3000 rpm (70mph) and it shot to 5800 and got a bit loose in the rear so I backed off.
I have never brought it to the track. I should mention I am running fi-tech on it now.

[Challenger340]

What is your cut off for rpm? are you running it to 6k? More? just wondering if it gets valve float up high. I am building my engine similar to yours with a little bigger hyd. cam and wonder if I am making a mistake. Probably should have used your cam. My cam is spect. at a couple hundred rpm higher than yours.

There is absolutely no way to determine what any particular Hydraulic Roller Camshaft will rpm to in an RB Mopar Engine, mainly because these Blocks were never BUILT or intended to run a Hydraulic Roller Lifter.... the Lifter Bores are far too short.... and the Oil gallery far too LARGE where it intersects the Lifter Bore.... with far too SHORT a wear area in the Lifter Bore below that Oil gallery.

In a nutshell what I'm saying is this....
on a  Block with very little Lifter Bore "wear"..... a particular Hydraulic Roller Cam may be capable of maintaining good power right to 6,000 rpm ?
then,
Same Cam installed in a Block with worn Lifter Bores.... may be all done making power at 5,200 rpm ! and no amount of tuning will increase the Lifter Pump up that can be maintained in the "Hydraulic" Lifter in the worn Bore !

That's what happens when you are trying to "balance" a Roller Cams more aggressive Lobes.... faster/harder opening & closing.... against... the ever also increasing V/Spring pressures required to keep things in contact with the more aggressive events...... with a "Hydraulic" plunger as the weak link ?
There is a point where the Oil pressure takes the path of LEAST RESISTANCE ..... and if that is OUT "around" the Lifter Body in the WORN Lifter Bore as opposed to INTO the Lifter to keep it pumped up ? = FAIL to maintain the intended Lobe profile or rpm.

[comet_666]

if I kept the 3.91 in the car instead of swapping to 3.23 maybe i would have an issue but not the case here.

[Alec]

I'm building one now, what size is your cam?

[comet_666]

https://www.howardscams.com/hydraulic-roller-camshaft-1959-1980-chrysler-383-440-2500-6400-howards-cams-723445-10