Another question about heads....487X
Thread Starter
Melting Slicks
Joined: Feb 2003
Posts: 2,529
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From: Auburndale Florida
2025 C2 of the Year ('64-'66) Finalist - Unmodified
St. Jude Donor '03-'05-'06-'07-'09
Another question about heads....487X
My 72 L-48 came with 487X heads. From what I have read the 487 castings came std on the L-48 and the LT-1. But I have never heard or read about the 487X on a Vette. I know it is period correct for the 71-72 production years on Chevy's. Any help on the performance or origin of these head would be helpful!!!
Thanks
Mark :chevy
Thanks
Mark :chevy
Safety Car
Joined: Dec 1999
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From: PA
Re: Another question about heads....487X
Mark,
The 487X heads began to appear on Corvettes later in the 1972 model year on both the base engine and LT-1 and continued in use until the end of 1972 production.
They are substantially similar to the 487 heads and I doubt that there is little, if any performance advantage.
Regards,
The 487X heads began to appear on Corvettes later in the 1972 model year on both the base engine and LT-1 and continued in use until the end of 1972 production.
They are substantially similar to the 487 heads and I doubt that there is little, if any performance advantage.
Regards,
Safety Car
Joined: Aug 2000
Posts: 3,711
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From: San Antonio TX
Re: Another question about heads....487X (mbeeman350)
The only difference between the 487 and 487X is that the X has 10cc larger intake port volume. As far as the difference when you consider the application between the 1972 base engine and the LT-1: Base engine used 1.94/1.50 valves, pressed rocker studs and softer (less tension) valve springs with exhaust valve rotator cups; LT-1 used 2.02/1.60 valves, screw-in rocker studs with guide plates, stiffer springs and a different retainer.
And you do not have an L-48 in your '72. 1972 was the only year where the engine didn't use a code. It is called Corvette Base Engine. It is the same engine that when installed in another chassis, like a Nova, would have received the L-48 designation. L-48 in '71 -yes, in '73 -yes, but not in '72.
And you do not have an L-48 in your '72. 1972 was the only year where the engine didn't use a code. It is called Corvette Base Engine. It is the same engine that when installed in another chassis, like a Nova, would have received the L-48 designation. L-48 in '71 -yes, in '73 -yes, but not in '72.
Racer
Joined: Jun 2001
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From: Sanford Florida
Re: Another question about heads....487X (mbeeman350)
487x are among the best, if not the best GM head of that era besides camelbacks or equivalent. They are the ones the circletrackers look for around here when they can only use the large chamber heads (and no camelbacks). On the flowbench, the 882's tend to be better, but the 487x outperform them on the dyno. Hey, GM had them making 350 HP stock, so with good valves and a valve job, you should have no troble making that either.
Le Mans Master
Joined: Feb 1999
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From: Hoosier
Cruise-In III Veteran
Re: Another question about heads....487X (boredsoIstrokedit)
I gasket matched and did some porting and bowl blending on 487 heads. It did make a low end torque improvement. I have no before and after numbers, just the difference in feel.
Thread Starter
Melting Slicks
Joined: Feb 2003
Posts: 2,529
Likes: 27
From: Auburndale Florida
2025 C2 of the Year ('64-'66) Finalist - Unmodified
St. Jude Donor '03-'05-'06-'07-'09
Re: Another question about heads....487X (mbeeman350)
My thanks to Gerry72 and BoredSoIStrokedIt for all for the help and avvice!
Mark :cheers: :steering:
Mark :cheers: :steering:
