One of ? L89 Nova for sale at Russo and Steele

[copo-2]

Mr70,

Of the 3 L-89 70 Chevelles you mention, would you happen to have information concerning the possibility of them being produced early in the model run or not?

92646,

The 11:1 TRW piston worked just fine without modification in my motor. However, it seems a .040 head gasket was used as we weren't sure about how much compression we could run on pump gas with the alum. heads? As for the domes, I don't think it would have been an issue with a thinner head gasket?

[Mr70]

Yep because they started life as L-78's,they were early assembled cars too.August-Nov 1969.



....post photos please

Dan
Two owners are/were on TChevelle 9 years ago..One has posted pix publically of it's restoration.
The 2nd one won't,& the third doesn't care to get into a pissing match today.Say's he's keeping it anyway,so what does he care what others think.He's had it forever and will continue to do so.
All have sent me asorted buildsheets,P-O-P's,dealer shipper,engine stamping pix,whatever etc.After talking to them and seeing what each sent me,I fully believe these to be authentic and respect their privacy to the utmost.
These 3 cars are no secret to those who are enthusiastic about em,but there's just "more a$$holes then there are a$$es out there" as one of em put it.

[Kim_Howie]

I just wanted to know about one, not 18 of them. O K I didn't know about them.

[markjohnson]

The '71 LS-6 Corvettes are something I was also gonna bring up. I'm pretty sure Tonawanda just slapped the 118cc Open Chamber Aluminum heads onto a standard 11.00-1 closed chamber piston motor. This is gonna knock the compression ratio down to 9 or 10.00-1. I'm also pretty sure that the Crate LS-6 's that were produced for several decades as 10.2-1 Compression engines were done so by putting Cast Iron Open Chamber heads onto a closed-chamber piston short block.

[RPO LS7]

[ QUOTE ]
The '71 LS-6 Corvettes are something I was also gonna bring up. I'm pretty sure Tonawanda just slapped the 118cc Open Chamber Aluminum heads onto a standard 11.00-1 closed chamber piston motor.

[/ QUOTE ]
6262976

[70 Forest Green Zee]

This has been a very interesting thread, I've read every post from the first to the last. First off let me say I have a great deal of respect for Brian Henderson for the quality of work that he and his crew does, and his second to none knowledge of Chevy Novas. Here's my question and what I'm having a problem with: Brian was standing right there when the engine in question was disassembled so he obviously knows both what heads were on the engine when it was disassembled, and what pistons were in the engine during dis-assembly. These two components are basically what will determine the cars authenticity. Brian, you can end this right now by stating what were the heads and date codes during dis assembly, and what pistons were present at the time this engine was disassembled.

[kwhizz]

Dave............Still waiting for an explanation on the 1970 Head/ Piston combination for the 074 heads on a 396 block..........GM Piston Part#'......

[kwhizz]

After doing some research on the Piston/Head combo's.....Putting 074 heads on a L78 short block would yield approx 9.5 to 1 compression.....doesn't make any sense why the factory would do that in a High Performance application......there was also concerns about the posibility of the closed chamber piston dome hitting the 074 head in the exhaust valve area, even though the chamber was larger ..... Some hit....some didn't......so.....Why would GM put High Performance Aluminum Heads and lower the compression ratio by 1.5 points........Seems more likely that the heads were added at some time in the cars early life by someone who didnt know the difference..



Ken

[Charley Lillard]

Isn't that what they did with the 71 LS6 ?

[69SSZL1]

No, the 1971 LS-6 had a special piston used only in that application. It had valve reliefs and a special dome. The 9:1 compression was not a problem due to the larger 454 ci.