3.8" Wiseco Pistons to Clear a 2.04" Valve?
11-21-2017 | 05:24 PM
#42
Hahah I was trying to figure all that out in my head. Almost resorted to drawing pictures
11-21-2017 | 05:28 PM
#43
I wouldn't do it.
If you grab a 5.3L punch it out to 5.7L and go with a better piston. The rods and crank are good to 1k or so with the right tune. The pistons are too... but they are the weak link. At the very least, set the ring gap and run an LS9 gasket on it.
But if you have it apart to do that, go ahead and spend the $850 or so on a good shelf 3.9" piston, stainless ring pack, and upgraded pins. It's not a lot for some good peace of mind. Also, grab the ARP rod bolts and have the machine shop hone the rods after installing the rod bolts. Again, safe insurance. The only downside is the cost of the machine work, balancing, and the added backpressure from the added cubes.
If I do the 4.8L setup, I will definitely be doing the rod bolts as it will be spinning to 7K+.
Maybe even 7500-7800 if I grab an S475 83/1.10... at which point the short travel lifters and freer flowing heads will be a big plus.
If you grab a 5.3L punch it out to 5.7L and go with a better piston. The rods and crank are good to 1k or so with the right tune. The pistons are too... but they are the weak link. At the very least, set the ring gap and run an LS9 gasket on it.
But if you have it apart to do that, go ahead and spend the $850 or so on a good shelf 3.9" piston, stainless ring pack, and upgraded pins. It's not a lot for some good peace of mind. Also, grab the ARP rod bolts and have the machine shop hone the rods after installing the rod bolts. Again, safe insurance. The only downside is the cost of the machine work, balancing, and the added backpressure from the added cubes.
If I do the 4.8L setup, I will definitely be doing the rod bolts as it will be spinning to 7K+.
Maybe even 7500-7800 if I grab an S475 83/1.10... at which point the short travel lifters and freer flowing heads will be a big plus.
11-21-2017 | 05:37 PM
#44
My Lil' 218@.050" flat tappet hydraulic went to 65-6600 with hollow valved Fast Burn heads on a 385 inch
ordinarily that cam would nose over by 5200 NA in an engine that sized
11-21-2017 | 07:27 PM
#45
Thread Starter
Super Hulk Smash
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From: Pace, FL
Yeah... I have hollow-stem LS3 intake valves in my head too. I rev to 7000 no problem now. Can push to 7400... with a 227 LSL lobe.
The VE doesn't begin to fall off until 7500. I just don't want to push a stock LS1 and 4L60 to 7500 too much.
I attribute that to the 11/32 pushrods, lightweight valves, good springs, and short-travel lifters which are essentially solid at that speed.
Put that setup on a 5.1L combo with an even more stable LXL lobe... yeah.
The VE doesn't begin to fall off until 7500. I just don't want to push a stock LS1 and 4L60 to 7500 too much.
I attribute that to the 11/32 pushrods, lightweight valves, good springs, and short-travel lifters which are essentially solid at that speed.
Put that setup on a 5.1L combo with an even more stable LXL lobe... yeah.
