Question about the 1966 L-72

[442w30]

Hi . . . I have read several times that this motor was initially rated at 450 horsepower. Was this just for the Corvette or also big Chevys was the recipient of the initial 450-horse rating?

Thanks!

[olredalert]

----Just check out what RPM the 450hp was rated at. You should see that the 425hp rating was at a lower RPM. The lower rating was purely for insurance purposes. The two engines were functionally identical.......Bill S

[MarcDant]

1966 to mid 1969 the cylinder head used a bath tubbed shape closed combustion chamber.Possibly different cam grinds. But i have not seen a 427 450 horse air breather decal.

[WILMASBOYL78]

This should help...

http://www.chevelles.com/forums/showthread.php?t=369648

The L78 was the same motor 65-69..*the 1970 version was a 402..same hp rating..low profile intake

The L72 was the same motor 66-69...

Factory issues with HP ratings to satisfy insurance companies were routine...that L72 probably made more than 450hp if it was set up right.

either way both motors are awesome [img]<<GRAEMLIN_URL>>/biggthumpup.gif[/img]

[Day2_69Z]

Later tonight or tomorrow I'm listing a
'66 TO 215 IK 427 L88 that came from
&quot;the Best Damn Garage in Town&quot;
Pics may be delayed...

[442w30]

Thanks for the responses!

But all I'm trying to find out if the Biscayne/Bel Air/Impala/SS/Caprice were the recipient of the early 450-hp rating, or only the Corvette had that?

This is about how Chevrolet rated the L72 when it initially was released, not about real-world hp.

[Day2_69Z]

From what I understand Corvette only. ..
Memory tells me pass cars were 425

But there has been conversation to the contrary , that early cars were 450
Just as in '64..June, I believe ...they built a few dozen or so 327 /365 hp.... solid lifter, holley, aluminum intake etc ..for Chevelles, mostly if not all were SS Muncie 4 speeds.

Best bet is go over to Team Chevelle or similar site

[442w30]

Thanks . . . but did you really mean Team Chevelle? I'm trying to find out about the big cars as the Chevelle never received the L72 motor in 1966.

[mssl72]

I've never seen or heard of a '66 L72 passenger car that had a 450hp decal from the factory. I've heard of Corvettes coming that way and I have seen one. I always had heard what's been mentioned already in regards to the insurance issue. Chevrolet always seemed to want to keep the Corvette at the top of the heap. My feeling is that both L72's, Corvette and passenger probably started out as 450 and 425 respectively, but the insurance issue forced Chevrolet to knock the Corvette down to 425. At that point I don't think they'd knock 25hp off the passenger cars to 400 to keep the Vette on top. I believe the 450 Vettes were fairly early. I've seen GM proving grounds picture dated 11-15-65 that shows a '66 L72 Vette engine compartment with a 425hp decal.

[Tracker1]

450HP decals on '66 Corvettes have been documented in Sept., Oct., Nov., and Dec. of '65. But strangely enough, the owners manuals for those cars quote the 425 hp figure - 450 does not appear anywhere in the manner.

Diego, the Impala guys I have been talking to have no docs or anything in their database on 450 HP-decaled big cars in '66.