'New' '66 joins fleet...

[Michael G.]

[Mark F.]

Re: 'New' '66 joins fleet...

...I have two questions: I assume my manifold is original, but what is the proper manifold part number for the 390 horse engine?... Thanks,

MG,

I'm thinkin' a 1966 L36 390 cast iron intake manifold casting number (not part number) is 3866948

[Michael G.]

[Patrick B.]

Re: 'New' '66 joins fleet...

The weak parts on a 1966 427 are the main cap bolts with female thread standoffs for the windage tray and the valve springs (single spring with damper).

[Michael G.]

Re: 'New' '66 joins fleet...

Patrick,

My friend tells me that the springs have been changed, so that’s good, I think.

Sorry, I’m not comprehending the design of the cap bolts. Are they bolts with a tapped hole in the top of the head or bolts with a male threaded stud protruding from the top of the head?

Thanks,

[Patrick B.]

[Michael G.]

Re: 'New' '66 joins fleet...

Interesting, sounds like the depth of depression in the bolt head was excessive. Can you tell me whether the fracture was across only the bolt shank or through the tapped hole in the head?

[Patrick B.]

Re: 'New' '66 joins fleet...

Interesting, sounds like the depth of depression in the bolt head was excessive. Can you tell me whether the fracture was across only the bolt shank or through the tapped hole in the head?

The breaks had nothing to do with the standoff itself or the threaded hole. The bolts broke at the threads going into the block. It seemed like the heat treatment was wrong and the bolts were brittle. The change in design was to a part of the bolt that was not the failure point. It's just that the only main cap bolts I have ever seen break were those particular windage tray standoff bolts. The regular main cap bolts on those same engines torqued up properly and caused no problems. On one engine three of the standoff bolts snapped one after another during the torqueing of the main cap bolts.

[Larry E.]

Re: 'New' '66 joins fleet...

Patrick>Was the setup on the windage tray bolts identical on both the L36 & L72? Thanks>Larry

[Michael G.]

[Patrick B.]

Re: 'New' '66 joins fleet...

Patrick>Was the setup on the windage tray bolts identical on both the L36 & L72? Thanks>Larry

I think so. The engines I had experience with were 4 bolts, but the stand-off bolts were inner main cap bolts so they could be used on 2 bolt blocks as well.

[Michael J.]

Re: 'New' '66 joins fleet...

Now that you have a beautiful '66 427, you need to watch the best movie starring a '66 427 ever made. It has an all star cast, was shot entirely in New Mexico, mostly within 50 miles of my place, and the Corvette featured in it was a local NCRS member's car........https://www.imcdb.org/v641924.html

https://www.imdb.com/title/tt0105813/

[Larry E.]

Re: 'New' '66 joins fleet...

Mike>You will also have to listen to the song>David Ball "Riding with Private Malone" is about a 1966 Corvette. Larry

[Michael G.]

Re: 'New' '66 joins fleet...

As I prepare to drive this car in the Spring, it bothers me a bit that it really hasn’t been driven much for 50 years. While I have no intent of racing it, its not beyond the scope of possibility that I might wind it out once (or twice, maybe). It’s only got 53,000 original miles on it, so its probably not breaking apart at any point soon, but I’d hate to lunch an original 427 engine. I’m almost thinking that I should put it on a stand and get a new long block, but it runs so well and makes such nice noise, that that would be a shame… It’s a good dilemma, sure, but I have mixed feelings, HELP!

FE5B81CE-E774-43A6-A816-A008CD6E64CD.jpg

[Leif A.]

Re: 'New' '66 joins fleet...

As I prepare to drive this car in the Spring, it bothers me a bit that it really hasn’t been driven much for 50 years. While I have no intent of racing it, its not beyond the scope of possibility that I might wind it out once (or twice, maybe). It’s only got 53,000 original miles on it, so its probably not breaking apart at any point soon, but I’d hate to lunch an original 427 engine. I’m almost thinking that I should put it on a stand and get a new long block, but it runs so well and makes such nice noise, that that would be a shame… It’s a good dilemma, sure, but I have mixed feelings, HELP!

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Michael,
The only way you'd "lunch" that engine would be lack of maintenance or abuse i.e. missed shift at high RPM. I seriously doubt you're going to be doing anything that would destroy that engine. Drive on and enjoy what you bought.