1969 "512" engine block 2 bolt to a 4 bolt........

[John P.]

What will it take to change a 2 bolt 1969 512 427 engine block into a 4 bolt 435 hp block.

I know I can have the main caps machined and then with new 4 bolt caps have it center lined bored so the caps are straight, but is there anything else I need to do for this restoration...

I have read that all BB had been drilled for Oil cooler conections and I have also been told that my 435 hp car was not set up for this so the block was not drilled for the vettes?

Is there anything aside from the main bearing caps that I need to have done to make it right?

[Joe L.]

Re: 1969 "512" engine block 2 bolt to a 4 bolt....

johhny-----

Special high performance big blocks (i.e. original solid lifter engines) were drilled and tapped for oil cooler provisions. Hydraulic lifter engines usually were not. A 1969 L-71 would have had the drilled and tapped block. Also, on the block in the vicinity of the oil cooler fittings were the cast-in words "hi-perf pass". I don't recall, at the moment, if hydraulic lifer versions got this, or not.

To convert the block to 4 bolt mains is done as you describe.

[John P.]

Re: 1969 "512" engine block 2 bolt to a 4 bolt....

Well I would think that they are all cast the same with the same casting number I dont have the block in my posesion right now but I will have to find out if that casting is there.

What would I need to do to drill these passeges in the block.
It was just for the oil cooler correct?
then it was pluged?
Any one have some pictures they could send me?

johnny

[Clem Z.]

Re: 1969 "512" engine block 2 bolt to a 4 bolt....

i have a 439 4 bolt block here and it has the oil cooler tappings but all the different web sites that list a 439 list it as either a 4 bolt or 2 bolt so i would guess the 512 block could be the same and it may have the ability to be drilled for the oil cooler fittings. if you are doing this just for NCRS judging and the block casting is the same you only need to drill and tap the external wall of the block to install the correct pipe plugs because you do not need the different oil gallerys in the engine for the cooler. unless you are planning to race this engine i would not even bother with converting the 2 bolt to a 4 bolt because the 2 bolt will support 500+ HP

[Mike M.]

Re: 1969 "512" engine block 2 bolt to a 4 bolt....

clem is right on. if its to be an ncrs beauty, just drill and tap for the pipe plug . i've seen it done before with a 962 two bolt main some turkey wanted to pass off as a 4 bolt main 962. I don't think there is any significance to the high perf casting you refer to in your post. i've seen many 942 , 962 and 35l 2 bolt mains that had the high perf cast into the case. good luck. mike

[Joe L.]

Re: 1969 "512" engine block 2 bolt to a 4 bolt....

johnny----

Like I said, I don't know if all '512' blocks got the "hi-perf pass" cast on them. I seem to recall seeing some blocks which just said "pass". The '512' block was used for many applications and it's VERY possible that the casting embossments were different. Many casting embossments vary for a certain casting number; I don't see why the "hi-perf pass" embossment should be any different. In any event, it's a moot point. If the '512' block you have is embossed "hi perf pass", then you have exactly what you need. Add the tappings and plugs to the bosses as Clem and Mike advised and you're done. On the other hand, if the block doesn't say "hi perf pass", then it's not right. I doubt that's going to happen, but I just wanted to raise the POSSIBILITY in my previous post lest you be "lead down a primrose path" and tell others that I told you that all '512' blocks have the high-perf pass" embossment.

Also, although I didn't mention it in my previous post on the subject, I agree with Clem regarding leaving the block a 2 bolt, as it is. There is no real need to convert to a 4 bolt for street operation, even spirited street operation. Plus, I can guarantee you that it's not a feature that the car will be judged on. The judges with the x-ray eyes are all gone now. RIP.

[John P.]

Re: 1969 "512" engine block 2 bolt to a 4 bolt....

Well I plan to restore the motor and in my eyes that means to make it a 4 bolt block so that it is correct, Yes the bottom of the motor will not be judged but lets say I did that it made top flight I sold it as a restored car and when the new owner decided to drop the oil pan and see's 2 bolt mains I wouldnt want to be that guy and I wouldnt do that to someone because im not a turkey

[Craig S.]

Re: 1969 "512" engine block 2 bolt to a 4 bolt....

Johnny - I understand....kind of like the way I am building my 66 L72 back to original specs with the correct block, pistons, cam, etc etc...just so I know it is exactly as it was and should be. Probably not as practical as other options for driving today, but in my gut I know it is right....and exactly what's in it....Craig

[Craig S.]

Re: 1969 "512" engine block 2 bolt to a 4 bolt....

Johnny - I may also have some close up pictures of the filter boss area on a 66 942 block if I didn't erase them, the drilling would be the same. Send me an email from this website so I have your email and I will send them if I can find them....Craig

[John P.]

Re: 1969 "512" engine block 2 bolt to a 4 bolt....

I wont go around telling everyone that you said it is the law
But Im restoring the motot and that to me means to restore it to original specs and that would be to have 4 bolt mains because If I bought the car and pulled the pan and I saw 2 bolt mains I would be pissed!

johnny

[Joe L.]

Re: 1969 "512" engine block 2 bolt to a 4 bolt....

johhny-----

Then, by all means, convert it to 4 bolt mains. No problem, at all. Also, if you decide to have the original VIN derivative or engine code stamped on the block, make sure that you tell anyone that you might sell the car to that it's a re-stamp. Otherwise, if they later find out, they might get "pissed".

[John P.]

Re: 1969 "512" engine block 2 bolt to a 4 bolt....

Oh of course!
But with the restoration that would all be included...
But Im still not sure about restoring the stamp pad and having a block restamped I see it in some of the publications but its a touchy subject