[BBPanel]

I picked up a 396 block (3855961, T0124EDH 6K151402) several years ago to use for mock-up and now have no need for it. It also has a set of mis-matched heads(781, 236) and a 10/10 454 crank. I used a dial caliper (didn't have anything else) and measured an average of 0.055" overbore so I assume its really 0.060".

I'm guessing its a boat anchor but wanted to check before I junk it. Can these blocks go 70 or 80 over? Probably not worth my time to have it sonic checked. Thanks. -Bob

 

[Geo71]

I picked up a 396 block (3855961, T0124EDH 6K151402) several years ago to use for mock-up and now have no need for it. It also has a set of mis-matched heads(781, 236) and a 10/10 454 crank. I used a dial caliper (didn't have anything else) and measured an average of 0.055" overbore so I assume its really 0.060".

I'm guessing its a boat anchor but wanted to check before I junk it. Can these blocks go 70 or 80 over? Probably not worth my time to have it sonic checked. Thanks. -Bob

I ran a .030 over 402 block in my first chevelle. No issues.

 

[427L88]

Unless someone has VIN# 151402 it's just another small bore big block.

 

[rpol78]

I picked up a 396 block (3855961, T0124EDH 6K151402) several years ago to use for mock-up and now have no need for it. It also has a set of mis-matched heads(781, 236) and a 10/10 454 crank. I used a dial caliper (didn't have anything else) and measured an average of 0.055" overbore so I assume its really 0.060".

I'm guessing its a boat anchor but wanted to check before I junk it. Can these blocks go 70 or 80 over? Probably not worth my time to have it sonic checked. Thanks. -Bob

I have a 396 bored .090" that I ran in my camaro for awhile without any problems. The later 396s were .030 over (aka 402) from the factory and I know people bored those .060 over (i.e. .090 on your block). Mortec shows your casting as being used for both 396s and 427s.

 

[shovelrick]

Advertise it on CL as a 396/427 with 10/10 454 crank for a lower than reasonable amount instead of tossing it out, 1 mans junk is another mans treasure lol

 

[BBPanel]

Didn't think it would go +0.090 but sounds like its doable. I guess I'll see if I can sell it. Thanks.

 

[Tom Mobley]

Chevy used that block for 454s. What's the bore of a 454? Hint: it's 4.250, same as a 427.

Big Block bore and stroke
366T = 3.935" x 3.76"
396 = 4.096" x 3.76"
402 = 4.125" x 3.76"
427 = 4.250" x 3.76"
427T = 4.250" x 3.76"
454 = 4.250" x 4.00"
496 = 4.250" x 4.37" (2001 Vortec 8100, 8.1 liter)
502 = 4.466" x 4.00"
572T = 4.560" x 4.375" (2003 "ZZ572" crate motors)

T = Tall Deck

so, why be concerned about 4.125?

 

[66360horse]

I was wondering about this, I have one (961 casting) I was wondering about taking to 4.250 and making it a 427

 

[Ialone]

I have a 396" .060 (408") with an 871 on it 20% underdriven on pump gas, 755HP at 6700 and was still climbing.

My next BBC will be a 396-454 and a centrifugal supercharger...... but thats another story for another year

 

[Ericnova72]

Quick check to confirm if the cylinder barrels in the casting could go to 4.250" is simple...pop a core plug("freeze plug") out of the side of the block so you can access the waterjacket area....if it is cast to accept the bigger 4.250" overbore you will not be able to fit a common #2 pencil through the core hole and between the cylinders in the casting.

This is the "cheat" for a way to tell if the early 396 block is also cast to be used for 427 production.

If the pencil slides right in between the cylinders, it won't safely go to 4.250".

 

[supersport6667]

Have seen a few #961 blocks bored to 4.250 without an issue.