How can I tell a 383 block from a 350 SBC

Hi Guy's,

What do I need to look for on a block to know its a 383 instead of a 350. Have a really good deal on a short block that broke a couple of pistons on the nitrous. Guy is changing over to an LSx block. He reckons new pistons and bearings and it will be ok as there was no pysical damage to the cylinders.
Thanks,

Alex

 

most likely it is a 350 block. To make a 383 you use internal components from a 400 engine to achieve this...ghost

 

383's are made from either a 350 block or a 400 block. Difference is in the crank a**** other things.

 

A 383 is a standard 350 block that has been bored 30 thousands over ... making the bore 4.030 but it will have a 3.75 inch stroke crankshaft. The crankshaft is the key to the bigger inch displacement.

With one of the pistons all the down in the block ... it should measure 3 and 3/4 inches from the top of the piston to the top of the block.

 

Deuce Roadster is right. The crank is an altered 400 crank.

 

If you have a 383 block, it's a Mopar...a 350 block can be one of several things...

(Chevy, Olds, Pontiac, Buick or...Mopar!)

 

Correct me if I am wrong. But doesn't the block have to be ground at the rod ends travel area for clearance...ghost

 

A 383 can be made by using a 400 block and a 350 crankshaft ... and boring the 400 block. The 400 block is 4 and 1/8 inches ( stock ... not bored ) and the crankshaft will be 3.48 inches stroke. So the block will measure a little over 4 and 1/8 and when you measure the distance from the top of the furthest piston down it the block ... to the top of the block ... it will be 3 and 1/2 inches

 

Sometimes NOT ... if you use 400 rods ... 350 rods will require grinding

 

YUP!

383 BLOCK = MoPar. Have a look for the front mount distributor.

 

Chrysler also had a 350 big block way back in the day.......

 

Sure did...they're the only ones to have both a 383 and a 350!

 

This was a 350, 10.7:1 pistons and 238* Duration roller cam. Needed the info on the crank and rods.
Thanks

 

a 400 block with a 350 crank makes a 377 and the rev like a 327 apperently

 

383 is made from a 350 block with either a ground down on the mains 400 crank or an aftermarket crank. they can use either the 5.565 400 rod with a stock 350 piston ( which isn't done much anymore ) or the 5.700 350 rods with aftermarket pistons. is the pan off? if so post the crank forging number here. If there is no forging number it is likely an aftermarket unit-maybe **** or Eagle. Then it may have the mfg name and the part number on the front counterweight.

 

Doesn't a 400 SBC have 3 freeze plugs per side?

 

I've heard a 383 uses the 400 crank and rods with the bored 350 block? Not sure if that's correct or not, just what I've been told...

 

383's were oringinally done this way but the longer 350 rod gives a better torque curve hence the proliferation of aftermarket cranks designed specifically for the 3.750 stroke. The 400 crank needs .200 ground off the mains and this takes alot of work and is expensive to have done. These were built like crazy this way in the 80s and early 90s to the point that original 400 cranks are very hard to find now. Besides the long rod version is a better engine.

 

yes

 

Yes.

AND, there is a "383" Chevy engine. Known as a HT383, they have a one piece rear main seal. Its 4" Bore and 3.80" Stroke, 4 bolt mains. It has a block p/n 88962516 with factory roller cam. Externally they look like a late 350. They're kind of a pig as delivered though. Good base to add parts to.

BUT, that said.... there's a 99.9% chance the one you're talking about is a 350 block with a 3.75" stroke crank in it. Just turn the crank till a piston is all the way down, measure to the deck. It will be close to 3.5" for a 350 and 3.75" for a 383

 

Huh?!?!
The HT383 is a crate engine, not a factory production engine....


and


It uses the GM bare block part # 10105123

 

If it is a 350 bored and stroked (with the 400 or aftermarket crank) to 383 It should be externally balanced unless it does have an internally balanced aftermarket crank.

 

I have a 239" - aren't those cool anymore?

 

I got my info from GM, maybe they're confused

http://www.gmpartsdirect.com/result...ber=12499106&singlepart=1&partnumber=12499106

The part number you reference is for a 86-99 Gen I hd 350 block
http://www.gmpartsdirect.com/performance_parts/store/catalog/Product.jhtmlPRODID=631&CATID=628.html

Oh, and crate engines are factory production engines. This one produced by GM
http://www.gmperformanceparts.com/E...Id=HT383&engine=HT 383&sku=12499101&engCat=sb

Is it available in a GM car, NO but neither is a 502 or 572 and they are GM Production engines too.

 

LOL
It AIN'T a "383 block". It's a THREE FIFTY BLOCK.
End of story.

 

Here, it's a 350 block with MODIFIED PAN RAILS, that's what your "383 block" part# is.

http://www.crateenginedepot.com/store/383-Bare-Block-88962516-P938C13.aspx

 

around here we make 383's with a 350 block and a 400 crank.

 

SOME of them do, and some have only two...depends on the year of the block.

 

What it boils down to is....there is no difference. It takes a 350 block and 400 crank to make a 383.