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Discussion Starter #1
Hi all.

Ive 2 novas, 1970 and 72
70s got a crappy 2yo crate motor that's putting out 190hp, 72 (my wifes) is a 383. My manhood is at peril.

Anyway

I've been having some back and forth with a bloke about a "383" that he bought to put in his car, now hes selling the car yadda yadda, but cant back up the claim its a 383, its just what he was told by the guy he got it from. And that it goes good and had a holley 750. (what psychopath would have a 750 on a 350 is what I ask myself, some logic therefore in it being the 383) It was mated to a 700r4, not that that means anything, but my brides 383 is mated to a 700r4 also.

Am going to look at it tomorrow.

Doesnt want me to pull the heads off to be able to measure the stroke.

Thing is, its possibly a half decent donk.

3932388 tells me its from '69 (possibly) a 350/300hp
T1016HN on the machined plate front of head kinda supports that
Havent seen head numbers yet but suspect/hope theyre 3947041 (I'm sure someone here will be able to tell me the likelihood of that, but dates kinda tie in.)
Theres another stamp: NH9101L that's also on the front of the head that is utterly foreign to me.... can anyone shed light on that????

Now heres my quandary. IF its not stroked, Id be tempted to get it anyway as from what I understand its a pretty decent bit of kit. (unlike my 2yo 190hp crate motor)
If it is stroked, but has the 041 heads, whats the likelihood of major calamity down the line, or will these do the job? (this is for a weekend cruiser, not doing big mileage, or racing it)

Any help or advise would be appreciated.

Cheers team

Mark
 

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Hey mate, my first clue just looking at it would be precisely the tab on the block. Normally the block would be zero decked and when that machine work is done it wipes out any stamping on the tab. Is it possible it was re-stamped or does it look like the original stamp. I personally have built one stroker and I would not bother with re-stamping the tab since it's not original. It's not abnormal that some bloke would over carb a 350? You definitely got some manhood ground to make up. I wish you luck. :)
 

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Discussion Starter #3
Ha yeah, I do, cheers. Although i may be saved via the back door... shes selling hers.

The second stamp has me beat.

Thinking I'm just gunna buy it and be damned. If it is what its purported to be then all good. If it's not, then I guess I got a little mission to conduct.
 

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Check the balancer and the flexplate for a counterweight. IF by some chance the engine has some good parts in it it MAY be internally balanced. Otherwise a 3.75" stroke crank will be externally balanced.
 

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Check the balancer and the flexplate for a counterweight. IF by some chance the engine has some good parts in it it MAY be internally balanced. Otherwise a 3.75" stroke crank will be externally balanced.
I agree with bracket chev70, most street 383 small blocks are externaly balanced. Easiest way to check it.
 

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I cut and pasted this from another source. It may help:

These are the only casting numbers for 400 blocks

330817 1973 on, replaced 3951511
3951509 2 & 4 bolt, used a Flint engine plant, 70-71 and 74-75
3951511 4-bolt mains used in 70-71, used at Tonawanda engine plant, replaced by 330817

One of these blocks had 3 freeze plugs per side as opposed to two on all other 400's and every other small block made.
 

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Here in the states a 0.030 overbored 350 block is usually used (gm performance used a 880 casting 350 block for their 383 and ZZ4 crate motors) with 400 crank (externally balnaced) and rods and custom pistons but aftermarket cranks can be either interanlly or externally balanced for this, checking flywheel and harminic balancer isnt a perfect way to check, there is not an easy way to check for a 383 without actaully pulling the engine apart to visually inspect crank, rods and pistons which are the components that create a 383 along with the bore of the block
 

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Most 383 sbc engines require some grinding work on the oil pan rails and the underside the cylinder walls to gain clearance for the longer stroke crank.
Can you remove the oil pan to see if any material was removed from these areas?... should still be visible with the crank and rods in place.
399790
 
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