C4 Tech/Performance L98 Corvette and LT1 Corvette Technical Info, Internal Engine, External Engine

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Old Mar 8, 2015 | 08:17 PM
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If You have kept your LT-X over the years and MAKE MORE THAN 550 rwhp I WOULD APPRECIATE YOUR OPINION. I have recently completed some suspension work Added some 11 inch rubber and am looking forward to visiting the local track.

The engine is a 383 with 9.2-1 compression fed by a Vortech T trim. The heads and intake manifold are a set of ported and polished originals.

Before becoming a Floridian, I attempted to cure my traction problem by going to a larger blower pulley (3.25) and changing the CC 305
cam to a 600 lift. I was able to lose 40 horses along the curve and gained the original power back along the curve at about 4800rpm.
Power NOW peaks @ 5800rpm at 595 rwhp with 16 lbs boost.

PREVIOUSLY with the CC305 and a 2.75 pulley, power once peaked at 5800rpm@ 593 rwhp and 17.6lb boost.

If I go back to the 2.75 pulley, I wiil gain back the bottom end and maybe 10hp at the top.

The bottle neck appears to be the heads. I can't seem to break 5800
Would I gain much by going to a D-1R blower?
Is it worth the time to upgrade the heads?

Or at this point would a shot of nitrous be more cost effective?

Thanks in advance.

Randy Young
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Old Mar 11, 2015 | 03:29 PM
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Originally Posted by RVY
If You have kept your LT-X over the years and MAKE MORE THAN 550 rwhp I WOULD APPRECIATE YOUR OPINION. I have recently completed some suspension work Added some 11 inch rubber and am looking forward to visiting the local track.

The engine is a 383 with 9.2-1 compression fed by a Vortech T trim. The heads and intake manifold are a set of ported and polished originals.

Before becoming a Floridian, I attempted to cure my traction problem by going to a larger blower pulley (3.25) and changing the CC 305
cam to a 600 lift. I was able to lose 40 horses along the curve and gained the original power back along the curve at about 4800rpm.
Power NOW peaks @ 5800rpm at 595 rwhp with 16 lbs boost.

PREVIOUSLY with the CC305 and a 2.75 pulley, power once peaked at 5800rpm@ 593 rwhp and 17.6lb boost.

If I go back to the 2.75 pulley, I wiil gain back the bottom end and maybe 10hp at the top.

The bottle neck appears to be the heads. I can't seem to break 5800
Would I gain much by going to a D-1R blower?
Is it worth the time to upgrade the heads?

Or at this point would a shot of nitrous be more cost effective?

Thanks in advance.

Randy Young
Thanks for the personal replies.

RVY
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Old Mar 12, 2015 | 08:54 PM
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What does the graph look like from 5700-shift?
may be getting valve float.

full cam specs? what springs? Rockers?
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Old Mar 29, 2015 | 11:42 AM
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From: Mission Viejo California
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Originally Posted by RVY
If You have kept your LT-X over the years and MAKE MORE THAN 550 rwhp I WOULD APPRECIATE YOUR OPINION. I have recently completed some suspension work Added some 11 inch rubber and am looking forward to visiting the local track.

The engine is a 383 with 9.2-1 compression fed by a Vortech T trim. The heads and intake manifold are a set of ported and polished originals.

Before becoming a Floridian, I attempted to cure my traction problem by going to a larger blower pulley (3.25) and changing the CC 305
cam to a 600 lift. I was able to lose 40 horses along the curve and gained the original power back along the curve at about 4800rpm.
Power NOW peaks @ 5800rpm at 595 rwhp with 16 lbs boost.

PREVIOUSLY with the CC305 and a 2.75 pulley, power once peaked at 5800rpm@ 593 rwhp and 17.6lb boost.

If I go back to the 2.75 pulley, I wiil gain back the bottom end and maybe 10hp at the top.

The bottle neck appears to be the heads. I can't seem to break 5800
Would I gain much by going to a D-1R blower?
Is it worth the time to upgrade the heads?

Or at this point would a shot of nitrous be more cost effective?

Thanks in advance.

Randy Young
This is a very interesting question. The most I've seen out of a t trim on a ltx vette is 600 even at the wheels. On my fox body mustang, I was shooting for 700 with only 331 cubic inches. I'm not sure what the deal with these cars is. I have theorized that belt slip definitely plays into it. I have a ysi trim but I may as we'll have a t trim since I can't utilize the air flow due to slip.

If you get a set of nice aftermarket castings that flow similar to ls1 type ones, the car still doesn't pickup.the hp like a forced induction lsx type motor.

Ideally we would need cogs or at a minimum a 10 rib to get remotely close to getting big power out of these cars. The crank pulley size limitation makes it tough.

The pro chargers handle the slip better than the vortech a due to the step up ratio. I wish that my ysi could be regeared.
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