427 Chevy Block 2 bolt vs 4 bolt

[Rumbleguts396]

Hi Guys, I've been searching for a 1969 427 Chevrolet passenger car block for a future project for several months now. I really would like to find a 4 bolt main. Most of what I have found are already 30 over and needing to still be bored or are 60 over. Not really interested in that. When I find a nice standard bore or nice 30 over 4 bolt main they are way out of my budget. My question is has anyone taken a factory 2 bolt and drilled it for a 4 bolt main with good results? I've found some real nice standard bore 2 bolts in my price range. Is drilling to a 4 bolt as strong as a factory 4 bolt ? Anyone done this with good outcome ? Lucky I'm in no rush, so time is on my side for finding a good block within budget. My plan is to build a nice healthy solid lifter motor for a 1969 Camaro Street car with a few runs a year at the track. Mostly street driven. Many Thanks for thoughts, ROB

[Lynn]

I have a set of Milodon splayed main caps for an SBC to be used in an upcoming project.

Expensive, but some swear it will be stronger than the factory four bolt main cap block

They make them for BBC as well. No personal experience as far as testing.

https://www.jegs.com/i/Milodon/697/1...ontent=Milodon

[luzl78]

Originally Posted by Rumbleguts396

Hi Guys, I've been searching for a 1969 427 Chevrolet passenger car block for a future project for several months now. I really would like to find a 4 bolt main. Most of what I have found are already 30 over and needing to still be bored or are 60 over. Not really interested in that. When I find a nice standard bore or nice 30 over 4 bolt main they are way out of my budget. My question is has anyone taken a factory 2 bolt and drilled it for a 4 bolt main with good results? I've found some real nice standard bore 2 bolts in my price range. Is drilling to a 4 bolt as strong as a factory 4 bolt ? Anyone done this with good outcome ? Lucky I'm in no rush, so time is on my side for finding a good block within budget. My plan is to build a nice healthy solid lifter motor for a 1969 Camaro Street car with a few runs a year at the track. Mostly street driven. Many Thanks for thoughts, ROB

Tony (scuncio) has a 69 427-335hp complete motor

[scuncio]

Sorry, I sold that a couple years ago.

[luzl78]

Originally Posted by scuncio

Sorry, I sold that a couple years ago.

I’m tryin!

[Vortecpro]

Originally Posted by luzl78

Tony (scuncio) has a 69 427-335hp complete motor

I have those as well.

[big gear head]

It's not worth the effort for a street engine. I have a friend who is running a 396 in a B/S '69 Camaro running high 9s at over 8000 RPMs with a 2 bolt main block. If you can find a good 2 bolt block then it's going to be more than good enough for a very strong street/strip car. Too much machine work involved in installing 4 bolt caps on a 2 bolt block. After you get the caps installed you have to get the block line bored. If the rear cap doesn't fit just right you may have problems with the seal and thrust surfaces.

[Too Many Projects]

As Freddie said, a 2 bolt block is fine for street use. Find a 2 bolt 512 cast block and they are the same as the 4 bolt. I bought Freddie's 427/390 engine last year for just this purpose. It is standard bore and with a forged crank. The cast cranks and low performance rods were the main reason 2 bolt engines blew up at high rpm, not any fault of the block. Build the internals properly with a 2 bolt and you won't have any issues.

[Pro Stock John]

I might have a friend in MI who might have 1-2 blocks I'lll check.

[big gear head]

I have another standard bore '69 512 short block. It's a 335 horse.