lib

The TV talking head at Mecum auction in Anaheim said today, "This 427 with 390 hp has the hydraulic lifters and the optional 4 bolt mains". Were 4 bolt mains an option in 67?

sub006

Maybe they were only standard on higher-redlined solid lifter engines?

I always thought all the basic parts were the same on 427s, regardless of power rating. Never heard of any such difference, much less an "option" for hydraulic lifter engines.

C'mon JohnZ, this one's for you!

Nowhere Man

L71/L89 and L88 are the only ones to get four bolt mains. No such thing as a option. But all 67 427 were the "351" casting. Expect for a few real early and real late blocks.

rich5962

I say this with reservation because I never heard it before......

Ironically, just the other day while looking over a '67 L71 I have here in the shop, a friend and I were discussing this. He mentioned that some early/mid '67's, he owned a original block 427/390, and it had 4-bolt mains when he took it apart for rebuild. He believes some had them, some didn't. Just a observation on his part.

However, I don't believe it was ever a "option". IMO.....Maybe just inventory fluctuations from Tonawanda and they assembled and shipped what was available to keep the St Louis line moving.

DansYellow66

No option for 4-bolt mains, except to order a solid lifter motor. I would also seriously doubt that the assembly plant would ever substitute a 4-bolt block for a proper 2-bolt block on a hydraulic lifter motor. I don't recall ever hearing of a documented and verified instance of this(?). An urban legand like the big block hoods on small block cars.

63Corvette

The four bolt block is different from the 2 bolt block. JohnZ has posted pictures of the oil cooler provisions over the oil filter. The heads are also "very" different. They are two different engines, (block, pistons, heads, cam) period.

DZAUTO

ALL of the above is good information.
True, it is POSSIBLE that a low perf BB COULD have gone down with a 4-bolt bottom, but it is unlikely.
Although, it is TOOOOOOOOOO EASY to convert a 2-bolt block to 4-bolt, I've personally had my machinist do it to a few. The cap register on 2-bolt and 4-bolt blocks is the same (unlike 2-4bolt SBs). Thus, rounding up a set of 4-bolt caps and having a good machine shop install them is too easy. ALLLLLLLLLLLLLL the 366 truck and tall deck 427 truck blocks had 4bolt mains. In Okla City there is an engine salvage place where I used to go and buy sets of 366 truck caps for $10/set. I still have 2 sets in the attic. At one time, 366 truck blocks were as common as dirt.

sub006

Thanks! You may be a worthy Forum successor to JohnZ, many years from now.

SI67

You sure it was his HEAD that he was talking out of?

Nowhere Man

If you have the machines you can machine out a two bolt block and make it look like a four bolt block.

JohnZ

If it had hydraulic lifters (427/390), it got 2-bolt mains. If it had solid lifters (L-71, L-89, L-88) it got 4-bolt mains and drilled/tapped bosses for external oil lines; same block casting, different machining. There was no "option".

Procrastination Racing

The two bolt main had a smaller hole in the center pad and none in the forward one. The four bolt main had a larger hole in the center pad and a hole (typically plugged unless you ran an oil cooler) in the forward pad.

396 Oil Pad

427 4 bolt main

427 2 bolt main


He is an auctioneer, for crying out loud, not a Corvette expert. Basically, he is probably on the same step as a used car salesman.

DZAUTO

It doesn't make any difference who he is. It's incorrect information like this, made by unknowledgeable persons like this which are one of several sources of information which is picked up by, and passed along by others and eventually becomes accepted by enthusiasts and the public to be correct information. Some of these things are simply passed on by people who heard or read it somewhere else, or, even worse, by people who are full of BS and are trying to make a fasle reputation as an expert. NO ONE ever wants to confront and correct these people because they don't want to cause trouble--------------in my book, this is just as wrong. Confront them, explain and demonstrate to them that the information they are professing to be accurate is NOT correct. If it humiliates them in front of others, they will be less likely next time to pass on incorrect information, either because they don't know the truth, or because they are trying to impress someone, such as a girlfriend.

lib

"He is an auctioneer, for crying out loud, not a Corvette expert. Basically, he is probably on the same step as a used car salesman."

It was not an auction employee. It was an NBC commentator. I suppose the comparison that you used above could still hold true for him also...