will 317 heads work on my ls1
It hasn't been a secret to me for a while. 
06-11-2012, 04:44 AM
#22
Apparently to everyone else it has been. It amazes me that engine dyno tests have been done on little 224 cam only LS1s on the engine dyno where the FAST picked up almost 20/20 over an LS6 and people still think anything under 450rwhp wont see gains
06-11-2012, 04:53 AM
#23
No secret. I see dynos from bolt on cars swap from a ls6 to fast setup and gain... BUT when u have a mild-high lift cam the volume and big runners from the FAST help that cam work to full potential.. squeeze out every pony lol
06-11-2012, 04:54 AM
#24
06-11-2012, 05:39 AM
#26
I recently built a LS1 that made 448 rwhp naturally aspirated. 243 heads with oversized valves and ported by Elliot portworks, 227/231 .614/.617 112lsa. Stock LS6 intake, stock LS1 injectors, single 3" exhaust, long tubes, no cats.
Mentioning the particular specs because your goal is 450.... This setup is choppy as hell and a little extreme for a daily drive in my opinion.
Mentioning the particular specs because your goal is 450.... This setup is choppy as hell and a little extreme for a daily drive in my opinion.
06-14-2012, 09:12 PM
#28
Well, actually, LT engines DO use guide plates (not from the factory though)...at least the aluminum head versions do, they have screw in rocker studs...you can get away with self aligning rockers on an LT1/LT4 if you keep the cam lift mild, but when you go big, you need to go to guide plates and non-self aligning rocker arms...and when you do that, yes you absolutely must also run hardened pushrods. Can't do that on an iron head LT1/L99 without pulling out the pressed in rocker studs first, then machining the rocker bases down lower, then drilling/tapping the holes for screw in studs...and at that point, you should really just invest the work/time in aluminum LT1 or LT4 castings anyways. Some Gen 1 SBC heads (iron ones) also have a guide plate of sorts built in to the head itself too...the pushrod holes are just wide enough to allow the pushrod through with support to align the rocker, and in that case, I believe those engines came right from the general with hardened pushrods.
06-15-2012, 07:34 PM
#29
Oh I'm not disagreeing that higher quality pushrods over OEM are worth it, especially when you also need a different length, or you want them to be lighter...but hardened has nothing to do with their resistance to bending, hardening on pushrods is a surface level heat treatment to the metal to keep it from galling/wearing on a guide plate. Gen 3 and 4 engines will never need guide plates due to the rocker base design, so hardening is not necessary. Using a better material that's just stronger and making them better in the first place certainly does have it's benefits.
Well, actually, LT engines DO use guide plates (not from the factory though)...at least the aluminum head versions do, they have screw in rocker studs...you can get away with self aligning rockers on an LT1/LT4 if you keep the cam lift mild, but when you go big, you need to go to guide plates and non-self aligning rocker arms...and when you do that, yes you absolutely must also run hardened pushrods. Can't do that on an iron head LT1/L99 without pulling out the pressed in rocker studs first, then machining the rocker bases down lower, then drilling/tapping the holes for screw in studs...and at that point, you should really just invest the work/time in aluminum LT1 or LT4 castings anyways. Some Gen 1 SBC heads (iron ones) also have a guide plate of sorts built in to the head itself too...the pushrod holes are just wide enough to allow the pushrod through with support to align the rocker, and in that case, I believe those engines came right from the general with hardened pushrods.
Well, actually, LT engines DO use guide plates (not from the factory though)...at least the aluminum head versions do, they have screw in rocker studs...you can get away with self aligning rockers on an LT1/LT4 if you keep the cam lift mild, but when you go big, you need to go to guide plates and non-self aligning rocker arms...and when you do that, yes you absolutely must also run hardened pushrods. Can't do that on an iron head LT1/L99 without pulling out the pressed in rocker studs first, then machining the rocker bases down lower, then drilling/tapping the holes for screw in studs...and at that point, you should really just invest the work/time in aluminum LT1 or LT4 castings anyways. Some Gen 1 SBC heads (iron ones) also have a guide plate of sorts built in to the head itself too...the pushrod holes are just wide enough to allow the pushrod through with support to align the rocker, and in that case, I believe those engines came right from the general with hardened pushrods.
