#270 blocks in COPOs?

[YENKO DEUCE REGISTRY]

The car belongs to another board member, and I guess he chooses to remain anomyous.

I can't elaborate any further since I'm not very knowledgeable about this subject matter.

[69rsss350]

Damn, that is down right upsetting, Marlin, I thought you knew it all! [img]/ubbthreads/images/icons/shocked.gif[/img]

[Chevy454]

More info:

I tore the block down a couple of days ago, and found that it's standard bore, all standard bearings, correct pistons/rods, steel shim GM head gaskets, stock deck height, and it all looked to have been together for a while. A late '68 270 block with the correct stampings, dated in mid-late February, all on a March car.

An interesting find, though, was what was on the top end. One of the heads was an 840, while the other was a 391. Now, this seems really odd, but maybe some background info is in order. We have always heard that our Camaro came with aluminum heads. We've had a couple of different people at different shows in the area say they remembered a yellow Yenko Camaro just like ours, except it had white stripes and aluminum heads. The stripes ARE supposed to be white, and the original owner said it had "special heads" on it, and a friend of his confirmed they were aluminum. He also told us soon after getting the car he "stretched a valve". You see, the original owner wasn't into the mechanical workings of automobiles, so details are sketchy at best. But, he said that it took about 6 months and a call to a zone rep to get the car back from Francis Chevrolet. When he did, he said the heads were different, and he had a couple of different people tell him that Francis was known for "acquiring" parts off of customer cars, and that they had gotten his aluminum heads. Ironically, Frank Radake got the same treatment from Francis, but I don't recall what the car was returned for. This car was bought from a collector, unrestored, with less than 30k miles on the odometer. We will probably never know 100% whether it is or isn't the original short block, but it kind of makes us wonder...

[JoeC]

Rob, Do you have your VIN number stamped at the oil pan location?
Frank blew his engine under warrantee and Francis refused to fix it. About 80 percent of the original owners I have talked with, blew up their original engine. There are even some low mile 427 COPO cars with old CE blocks installed early in the cars life. In my opinion, there is a slim chance that any 427 COPO has it's 'real' original engine. The solid lifter BB would rev too high for its own good.

[Keith Tedford]

I must be one of the lucky ones to have the original drive train. Most L78 and L72 engines, that I have heard of, died from dropped valves. This is what happened to our L78 car as well. The valve springs were too weak for over 6000 rpm use. The valves could not keep up with the valve train. They would slam shut at high rpm and eventually pull the keepers through the retainer. I was told that the COPO 427s were honed to the outer clearance limits allowing the engine to rev feely at higher rpm. 7200 rpm was effortless. Ask Peter Simpson who should know as well as anyone about the abilities of these engines. As far as casting numbers. There probably was an overlap of numbers during transition from one design to the next. The switch from closed to open chamber heads on the L88 Vettes was a rolling production change during the year. I was told that the L88 Vette that Beare Motors sold in '69 came with closed chamber heads when they were supposed to have open chambers. If we come up with enough information, patterns will emerge.

[Chevy454]

Yeah, the VIN# is on the oil filter pad. As for the overlap of parts, I wonder if it's the same kind of deal as with our 840 heads with the 1.88 valves...done in the middle of a switch over.