mbeeman350

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

Rowdy Rat

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,

gerry72

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.

boredsoIstrokedit

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.

AlwaysWave

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.

mbeeman350

My thanks to Gerry72 and BoredSoIStrokedIt for all for the help and avvice!
Mark :cheers: :steering: