was all 427 big block were 2 or 4 bolt main ??

[Frank Bernier]

Hi guys

was all 1969 427 block were 2 or 4 bolt main ?

427 block 39354439 or 3955270

390 HP - 2 or 4 bolt main ?
400 HP - 2 or 4 bolt main ?
435 HP - 2 or 4 bolt main ?

what should be right ???

my vette is an early 69
thanks alot Frank

[Joe L.]

Re: was all 427 big block were 2 or 4 bolt main ??

Frank-----

390 hp-----usually 2 bolt

400 hp-----may be 2 or 4 bolt

435 hp-----all 4 bolt

[Dick W.]

Re: was all 427 big block were 2 or 4 bolt main ??

All hydraulic lifter engines normally had 2 bolt caps while solid lifter engines had 4 bolt caps. I have heard that a sporatic hydraulic lifter engine had 4 bolt caps, but I have never seen one.

[Norris W.]

Re: was all 427 big block were 2 or 4 bolt main ??

During my Corvette obsession I've had more '69's than any other single year. I presently have 5 '69 big blocks that I've owned for from 15 to 22 years. 2 have the original motors and I've seen the block from one of the others, but it was too destroyed to salvage. There were 2 others in the '80's (original motor cars also) that I disposed of in favor of other cars at the time. Of all these cars, I've never seen anything but a 3963512 casting number and I believe the earliest casting date of my cars is Jan '69, but seems like a couple of em were late '68 also.

I've heard of people claiming to have a 4 bolt 390 or 400 horse engine, but have never seen one. I DO have a friend with a 360 horse (hydraulic also) '66 Chevelle, with from what I can tell THE original block, so it probably has happened to some extent. It seems unlikely that GM would hold production if there was a shortage of blocks, and would more likely use what they have.

One other thing to remember is that the 2 and 4 bolt blocks are the same casting with the same casting numbers in a given time frame, and only the machining process is different. In addition to the 4 bolt main drilling, the cyl is chamfered at the top on the intake valve side to unshroud the valve on a 4 bolt block, which wasn't done on a 2 bolt (all 396 blocks, both 2 & 4 are chamfered in that area) and of course the 4 bolts were drilled for the larger oil cooler fittings above the oil filter, which generally makes them easier to spot. I have seen variations there also. A '68 396/375 Nova block that I bought out of an unsalvageable rust bucket probably 15 to 20 years ago, stamping matching the vin number of the car, and obviously original to the car was 4 bolt, but not drilled above the oil filter for the oil cooler, so variations are possible.

As far as 4 bolt variations on hydraulic lifter '69 427's, I doubt seriously that a 400 horse car is any more likely to have a 4 bolt block than a 2 bolt, given the fact that the build sheet for a 400 shows the L36 engine, then lower on the sheet the L68 as if it's an add on or a change. (at least mine does, so I'm assuming that's the way it was done)

[Dick W.]

Re: was all 427 big block were 2 or 4 bolt main ??

Norris, the earliest 512 4 bolt block that we have verified is about mid December '68, so there were several 270 and 439 blocks installed in '69's

[Norris W.]

Re: was all 427 big block were 2 or 4 bolt main ??

I'm assuming you're talking about the casting date??? I'll try to look at all of my 512's this week. I was thinking a little earlier, but my memory has just gotten ridiculous on details. (if it's this bad on stuff I'm REAL interested in you can only imagine what it's like on everything else)

[Mark #28455]

439 block 1969 435 HP # 6900 *NM*

[Dick W.]

Re: was all 427 big block were 2 or 4 bolt main ??

We have seen two bolt versions of the 512 earlier, but not four bolts.

[Steven C.]

Re: was all 427 big block were 2 or 4 bolt main ??

My Oct 68 car has a 270 casting.