BB 427 questions

Bill shuba · Guru

BB 427 questions

seventy2plus2 · Canadian Poncho Superstar!

You can't put a 454 crank into a 396 block as the large counterweights on a 454 will hit the sides of the block. In the late 69 model run, the 427 blocks had large reliefs cast in to them for the 454 cranks in preparation for the 4" stroke that was coming in 1970.
396's have a 4.094" bore,
396's & 427's share the same 3.76" stroke,
427's & 454's share the same 4.250" bore.

I find it odd a 4.094" bore 396 was punched out to 4.250" to make it a 427, that's 0.156". Those cylinder walls would be getting pretty thin, and would run very hot.

A bit later I'll look up the 961 block to see what the book says.

-- Edited by seventy2plus2 on Wednesday 19th of February 2020 10:40:08 PM

Bill shuba · Guru

Thanks Clint I find it all so confuseing..so many different views I have read in hind sight he has a 427 car so if he could have made a 427 out of it I think he would have ?? had it built then went with a LS5 454 Instead as story go's and don't see no reason not to believe him

Oh and by the way in no way did the fellow tell me it was anything else but a 396 with some work done to it...these questions I have is do to reading up on some sites to see how I could get some extra hp out of it..just wanted to make that clear..who knows he may even be a member haha thats it Bill cover your Butt haha..dam need another poncho miss this site !

-- Edited by Bill shuba on Wednesday 19th of February 2020 08:27:25 PM

-- Edited by Bill shuba on Wednesday 19th of February 2020 09:21:05 PM

seventy2plus2 · Canadian Poncho Superstar!

3855961 block 396 cubic inches

65-66 Passenger 325 hp

66 Chevelle 325/360 hp

2 bolt mains, canister type oil filter.

3917215 cylinder heads

67 late / 68 used on various engines

temperature sending unit boss is drilled and tapped.

I don't think you'll be making a 427 or 454 out of it.

koolconvertible · Poncho Master!

i am a member of a facebook page called chevy big block performance. The swaps and interchange they do are mind boggling. As long as you have the cash...

Fake68 · Guru

There are some 396 blocks and many 402 blocks that can be punched to 427 bore but... why? Just start with a 454 block and have nice thick cylinder walls.

Bill shuba · Guru

396 is my favorite big block had one bored 60 over in a 69 12 second nova when I was 17 and being 17 I drove the crap out of it sold it because at that time 60 over I thought was all it could be bored so pretty much done..I am not wanting a 427 out of it ,more of a question on how far it could be bored !! and hp it may have now and things I can do to up that also but not go crazy

W13 · Newbie

The 961 block was used for booth 396 and 427 engines. You won't know for certain till you tear it down and measure the bore. A friend thought he had a 396 till he tore it down to rebuild and found out that is was a 427 block. :)

seventy2plus2 · Canadian Poncho Superstar!

ok, so some feel the 961 block can be used for 396 & 427 bores.

Now for the big question, what is the stamping on the block? It'd be on the block that extends ahead of the passenger side cylinder head.

Bill shuba · Guru

Thanks Clint I won't know that till I pick it up..I am very sure its a 396 but would be interesting to know what it was in from factory..I am sure The fellow I bought it from will fill me in also !!

Bill shuba · Guru

ok TO 1191VR now some of those 1's maybe I"s { eyes} what can you tell me on that..? any idea of car type other than Pass ? thanks

-- Edited by Bill shuba on Sunday 29th of March 2020 04:03:23 PM

4SPEED427 · A Poncho Legend!

IV should be a 65-68 396 that had a TH400 behind it, R is for a Rochester carb.

Bill shuba · Guru

Thank you Carl...the work sheet says its a 65 but I can't find a stamp ? yep really don't know where to look not on back like the 327 ? after doing some internet looking 961 is a 66 but might be stamped 65 late for 66 model yr ?

-- Edited by Bill shuba on Sunday 29th of March 2020 04:35:55 PM

4SPEED427 · A Poncho Legend!

Can you find a date casting anywhere?

You know where the casting number is on the block behind the left head? On the opposite side, behind the passenger head is there a date code?

Either there or down on the side of the block there should be a letter, a space, one or two digits, a space, then one more digit. Something like A 14 6 would be Jan 14 1966

4SPEED427 · A Poncho Legend!

And yes, maybe something like J 10 5 for Oct 10 1965.

Bill shuba · Guru

I'll have a looky see I quess it maybe stamped by a frost plug by the starter ?? so says internet ? better get my glasses haha yep even with my glasses can't read it..oh well I'll go with the rebuild sheet and say its a 65.? what month and day ?? don't really matter..I did look at vin again with glasses and its tot191vr ?

-- Edited by Bill shuba on Sunday 29th of March 2020 05:40:19 PM

seventy2plus2 · Canadian Poncho Superstar!

To me, T0119IVR makes sense.
T = Tonowanda
01 = January
19 = 19th day of month
IVR = 1966 Passenger car 325 hp 396 with Rochester carb.

Identifying this block seems to keep going round & round.

4SPEED427 · A Poncho Legend!

Bill shuba wrote:
I'll have a looky see I quess it maybe stamped by a frost plug by the starter ?? so says internet ? better get my glasses haha yep even with my glasses can't read it..oh well I'll go with the rebuild sheet and say its a 65.? what month and day ?? don't really matter..I did look at vin again with glasses and its tot191vr ?

-- Edited by Bill shuba on Sunday 29th of March 2020 05:40:19 PM

The date code should be cast though (raised) not stamped (embedded) on the block. And if it's machined T0119IVR (which is logical) the date code should be around A 10 6 or something close to that. It will likely start with the A, end with the 6 and the digits in between likely between 01 and about 15.