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 <<GRAEMLIN_URL>>/biggthumpup.gif

[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.

[MosportGreen66]

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Tracker1</div><div class="ubbcode-body">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. </div></div>

The VIN cut off is often regarded as less than VIN 3000 but after legnthy discussions with top NCRS judges throughout the years of showing my former car, VIN 2800 is less is now accepted. My former 66 L72 was vin 2282.

Dan

[olredalert]

----I have seen several 450hp rated window stickers for 66 Corvettes. My cousin ordered a new 66 big-block Corvette in May of 65. When it came in just a week before opening day, I noticed that it was serial # 700 (even). It had a black air cleaner lid and only a 427 decal, no HP decal at all. My own 66 was delivered in May of 66 and was rated at 425hp. I have also seen 400hp window stickers for early 66 Corvettes that appeared to be 390hp. I owned an early 400hp Corvette. Wish I still had it. No big body 66 Chevys were ever rated at 450hp or 400hp in my opinion. The high rating was strictly a Corvette thing.......Bill S

[Nasblu]

I know of an original documented early L72 corvette that has the original protecto plate and window sticker and sales invoice. The car was built in Sept 65 and the sales invoice and window sticker both denote 450hp. The car was customer ordered car not dealer inventory car. What is also neat on very early 66 427 corvettes is that the hood catch is located on the passenger side unlike most 66 427 cars which on the drivers side. Gm used up left over 65 hoods modified to accept 1966 hood emblems and have no provision for driver side mount. This was done until they ran out of hoods then the redesigned 66 hood was used. I believe sometime around Vin# 3600 the transition happened.

[Day2_69Z]

Good stuff guys,,, real good.

The engine I have to list is what I feel is a 66 Chevelle 427 High Performance that came from the estate sale at
Smokey Yunick's Best Dam Garage in Town Auction sale in 2001 .
Pad stamp: TO215IK /small pad Stamped 'H Y'
Block Casting: 3869942
Date: need to remove excess paint.... will post.
Vin: 6K16201 ?
Heads: 3873858 Hi Perf X. B 3 6 'H YUNICK'
Alt: 1100696 42A. 6L8
Starter :
Pulleys:
Carb: (2). 3885067 EE
LIST 3246. 022 Date.
&amp; LIST 4781 - 3 2559. Date
Intake Manifold is the 'Mystery' 299 stamped
'H YUNICK' 3878299. Casting Date. 9-27-65
Also has an Original Chevelle Cowl Plenum A/C
with a Reproduction Cowl plenum to firewall.

Could this Be a 450 Horse or 425 Horse L72 ?
There was/is speculation to being an L88 recieved from Chevrolet for Deveopment by Smokey on this Engine. . . ..will pull the Pan to verify any Internals Casting #'s and or Part #'s.

I had a 427 66 Vette back in the day and it had a 425HP decal on the air cleaner.

[442w30]

Thanks, guys!

[DW31S]

I talked to an &quot;old timer&quot; today that ordered a '66 Biscayne 427 with the sole intention of running B/S. I asked about the 450hp and he claims that there was never a 1966 427 Biscayne rated at 450. The rating could have possibly changed the car to a different stock class; I don't know without grabbing and old NHRA rule book and doing some math. On a bit of a side note, he explained that his car took much longer to get due to a shortage of the 488s versus 410s and 456 rear gears. The fellow sold the car after a few seasons and then tracked it down and bought it back. &quot;The Untouchables&quot; is now reunited with it's original owner and has been at the York Reunion.

[mssl72]

The stamping on the block, T0215IK, points to a L72 Corvette. The major pieces, block, heads, are L72 parts. The dates are kinda scattered though, block assm. Feb.'66 model year build, heads Feb. '66, 696 alternator Dec. '66, 3246 (Passenger/L78 Chevelle) service date 1970, 4781-3 carb 2559 date, 1979? The block and heads could have been together from the beginning, but the rest doesn't seem to line up. Which makes me wonder, with all the resources Smokey had maybe he was just playing around with a bunch of parts and was gonna shove it in a Chevelle and have some fun? Yes, check the guts and see what's there.

[TAR6569]

So that the guy got the Biscayne back that he ordered new? I wonder if I have that one in my list?

[DW31S]

Called &quot;The Untouchsbles&quot; bronze in color