Hello everyone, i need yalls expert advise on this motor i just purchased. The guy sold the motor to me as a 383 stroker motor. I got the motors to the guy who is installing my motor and he said its no way its a 383 stroker because the balancer is so small on it. He should me another 383 stroker he had there and the balancer on it and it was much larger and weighted. So i took the number off the block its the gm3970010 but doing research its says it can be a numerous of engines from a 305 to a 350. Can anyone help me figure out what this is. How can i tell from the balancer what size it is, i looked online beacuse i was just going to measure it but they come in diffrent sizes also. By the way i called the guy i baught the motor from and told him my mechanic said it wasnt a 383 and he swore it was and the guy whom built it for him must had lied to him then and he would offer no refund back to me also so im stuck with this motor i have no clue what it is. Please help!!!

Hello, I am by no means the engine expert but I have built my own. The block number won't really tell you if the motor is a stroker. You need to measure the stroke by pulling off a head I would think is your first choice. Rotate the engine and measure the distance the piston travels from bottom to top or vise versa. Measure the bore while you are in there. When you find out this information you can determine what cubic inch engine you have. Plug them into this calculator: http://www.csgnetwork.com/cubicinchdispcalc.html

Here's an article I found with some numbers for you to look at.
http://www.carcraft.com/techarticles/ccrp_0808_383_stroker_small_block_chevy/index.html

Again I am not an expert just offering some information.

Normally a 383 uses a crank from a 400, or an aftermarket crank, and is "externally balanced." This means it will have a counterweight on the balancer and on the flexplate/flywheel.
However, aftermarket cranks can be made so they are "internally balanced", just like all other small blocks.

I have never seen an external balance balancer smaller than 8". Non-counterweighted balancers are available in a few different sizes, but usually an 8" balancer will be used anyway. Anyway, there's no way to tell what the engine is just from the balancer.

A 383 is a 350 block with a "stroker" crank in it. Instead of a 3.48" stroke it has a 3.75" stroke.

You need to see what crank is in it to know if you got what you were told you were getting.

A 383 is built from a 350 block.

The crank is changed out for one with a longer stroke to give you 383 CI of displacement. ie. "Stroker" motor
(Other parts need to be changed too but this is where the extra displacement comes from.)

Could it be a 383 with the wrong balancer or is it just a 350 (355)?
The 383 uses a 400 crank and those are externally balanced. Unless it's a relatively expensive aftermarket piece.
(Your engine installer is correctly suspicious. )

Here's a good write-up on this site for Crankshaft Identification. (http://www.nastyz28.com/sbcmenu.php)

The guy won't refund.... He blames someone else.... Shady deal, IMO. Expect a 350.
Now...... Was it really ever rebuilt? (Or was it a "rattle can" rebuild? :eek: )


Pull the oil pan and you can see the crank casting number. It's easier than pulling a head, IMO.
The head numbers are under the valve covers. Those numbers will give you more info about the engine.

Pull the oil pan and you can see the crank casting number. It's easier than pulling a head, IMO.
The head numbers are under the valve covers. Those numbers will give you more info about the engine.

Yeah I was going to suggest pulling the oil pan. Def easier than pulling heads....cleaning threads, etc and reinstalling with sealant and correct torque. I was thinking it would be easier to measure bore that way but you are right.

Never fork over money without
1. verifying for yourself what you are buying
or
2. getting a warrantee in writing with full refund spelled out.

I remember track officials had a device that screwed into a spark plug & could measure the displacement of a single cylinder; x8 would give total displacement. Might want to check around before pulling heads/pan, etc.

hey thanks so much everyone for the great advise, ill have to run to my mechanics shop and pull the oil pan off to see what it is. And yes next time i am for sure going to do more research before buying. It was supposed to be a friend of a friend so i though i could trust them, and the excitment of getting my camaro running again i guess got me too.

Just curious how much was this motor? I'd be suspicious of the small balancer but maybe the guy got it with no balancer etc. and it was the only balancer he had and didn't know it needed a different balancer. If it isn't in the car i'd flip it over and check for crank casting number by removing the pan. As stated above he may have been burned the same way and you are getting fall off. Sucks but some people got no conscious when it comes to greed.

i only paid a 1,000 bucks so it was a steal of a deal,and it was supposed to be a deal that hey you know myfriend and ill give you a "hook up" because its just setting in my garage. He said he had it in a 80's grand national, but who knows really were he got it from.My friend said he owns a small used car lot so my fear is that he pulled it out of some car and has no clue nothing about it now.It has a holley carbs four barrell and eldelbrock intake with the breather ports in the front. the motors is still out the car. Once my mechanic told me it wasnt a stroker i told him to hold up until i found out what it was. Doing research online if its a 305 i dont want it. From the research they have alot of issues and problems.

Just because the guy put a cheap balancer dosen't mean diddly. I love how folks will always find a way to bust your balls when buying something. So go buy a nice balancer, will that make em happy. I say put the motor in and tell him to zip it!

a balancer has NOTHING TO DO if it is stroked!

don't even pay attention to external vs. internal balance either. That is a thing of the past. When the aftermarket wasn't out there, the only option was to purchase a 400 crank. Now a days that is not the case.

There are a ton of companies that manufacture an internal balanced stroked crank.

Your best option is to pull a head and verify how much "stroke" the motor has. I have no idea how you could tell them by pulling the pan as it is really tight in there to measure stroke. Only input on pulling the pan is maybe you can see if they had to clearance the block or rod bolts.

You can pull the pan & measure the difference in the pistons from bottom of the stroke to the top. It won't be exact but the difference from 3.48 & 3.75" stroke will be pretty clear. That way it only costs you an oilpan gasket set not the intake & head gaskets.

I have a internal balanced 400cid engine in my car & have had people look at the front of the engine & argue with me that it is only a 350 based on the balancer.:rolleyes:

Could just be an internal balance crank, when I bought my 406 crank it was supposed to be external balance, but when my machine shop went to balance it they called and said it would be much easier to balance internally, they would have to drill a ton of holes to balance it externally or just use a couple small pieces of mallory metal to internally balance it, so I bought a different balancer and let them do it the easy way.
You just need to verify the stroke and go from there.

Later
Mike

You can pull the pan & measure the difference in the pistons from bottom of the stroke to the top. It won't be exact but the difference from 3.48 & 3.75" stroke will be pretty clear. That way it only costs you an oilpan gasket set not the intake & head gaskets.
....

Exactly... If it's a stock 400 crank, you'll see the casting numbers.
Aftermarket crank, you can measure the piston travel from the pan side.

You'll be able to see any clearancing which may have been done for the longer stroke too.

O.K. thats some more good info to know thanks. Another questions the camaro was a v6 and im replacing it with this motor. I have a 350 turbo transmission in the car and a rear end from a 70 monticarlo in it aswell my dad all put in the car from 1988. Now what are someother things i will have to change over. Will the radiator have to be replaced? Brakes? my speedometer cluster? Just curious whatlese im going to have to get.

I remember track officials had a device that screwed into a spark plug & could measure the displacement of a single cylinder; x8 would give total displacement. Might want to check around before pulling heads/pan, etc.

Ive seen that too. Thats the way they did it at the dirt track as I recall.

Front brakes are the same.
Rear brakes... I think they are the same for a 1st gen Monte.
If the V6 had A/C, it should have the heavy duty radiator so that should work.

Instrument cluster...No change, except for the tach. (If it has one.)
You just need the right speedo gears to match the rear gears and tire size.

You'll need a different fan shroud or you can shorten the V6 one.

Motor mounts get bolted in a different place for the V8 swap but the holes are there.

Rest asured it's not a 305...3970010 casting # was used only on 4.00" bore blocks (302, 327, 350)

The damper means very little. Any SBC damper will fit on any SBC engine.

The 2 main diff is the size. You have 6", 6.75", and 8" Then the balance type internal balanced or external balanced. You can get both in 6.75" and 8" sizes.

Most common 383 builds uses an extranal balanced crank, meaning the damper and flexplate will be weighted.

With the strong aftermarket now, you can also get intranal balaNced 3.75" stroke cranks, so you could build a 383 using intranl balance and common sbc damper

Only way to know for sure is gonna be to measure the stroke lenght or get the casting number or part number off the crankshaft

if you only payed 1000 you have not done your ass unless its stuffed...so do what everyone has been saying and in 1 hour you can know what your dealing with. i would be pulling heads and pan and going right over it before putting it in a camaro as the crossmember prevents you from pulling the pan in the car anyway. there could be a damaged bore with a sleeve job or something else in their..... the cost of some stud sealer, gaskets is well worth a peek.

You'll be able to see any clearancing which may have been done for the longer stroke too.
i would think this is the quickest way to tell without running numbers, right??

if you only payed 1000 you have not done your ass unless its stuffed...so do what everyone has been saying and in 1 hour you can know what your dealing with. i would be pulling heads and pan and going right over it before putting it in a camaro as the crossmember prevents you from pulling the pan in the car anyway. there could be a damaged bore with a sleeve job or something else in their..... the cost of some stud sealer, gaskets is well worth a peek.

X 2

I just bought roller motor with build sheets from two machine shops but still pulled it apart to swap heads and lopk over some internals. You only get one shot at this with it on the floor stand and it's simple right now.

Buy a set of gaskets for motor and rip er up and see what ya got bro. Pop the heads off first and write stuff down. You said you have concerns if it's a 305, pulling heads will help tell that immediately and check what heads/ rockers you have. IF it has some newer parts like GM heads that are more modern it may be a yanked engine. That intake and carb can be thrown on any motor quickly.

After heads are off roll her over and pull off pan. ( take photo's for seller )

If it's junk you can embarrass him big time.

My 412 is internally balanced. Aftermarket.

Yank the pan. read the numbers. Call it a day.

-- Joe

for 1000 dollar engine ...put it in and if it runs you got your moneys worth.

for 1000 dollar engine ...put it in and if it runs you got your moneys worth.
if you do that might as well just run it on the floor before you put it in.

my mechanic told me the size of the balancer is a good indication on whether it's a 2 or 4 bolt main - can anyone comment on the truth of that?

but like what was said, if it runs you didn't get taken.

My mechanic has a 355, he's asking $ 4,000.00 for it and it has over $ 8,000.00 in it, so to get something for a thousand, you're laughing

the thing too is that unless you buy an engine new, or have it built or do it yourself, someone can talk it up all day. But really it's like going for a grab bag and hoping for the best. Even in my case, I have no clue about the internals so it's impossible to tell without stripping it down. But the good thing is it's a chevy block and the 350 is bulletproof

Dynobrat... There is no relation to damper size and # of main bolts.

Here's my take on it from the years of working on these things..

Stock.. 265, and some early 283s had no damper, just a hub
283, 327, 307 had 6" dampers that was thin, the high output 327's got the 6.75" damper, so did the early 350's.

Then all 350s, 305, 400s went to an 8" damper. The 305's damper was thinner than the 350's, and the 400's was external balanced

Now over the course of years, parts gets swapped so no telling what you might find put on what ever engine.

I know myself I use 6.75" dampers on alot of builds for less rotating weight

my mechanic told me the size of the balancer is a good indication on whether it's a 2 or 4 bolt main - can anyone comment on the truth of that?


Fire your mechanic. Sounds like an idiot.

-- Joe

Sounds like your "mechanic" dosen't know squat - maybe he's the one taking you for a ride.
1. size of balancer does not dictate stroke
2. size of balancer does not dictate 4 or 2 bolt mains
3. $4000 for a $8000 engine??? LOL

The quickest and easiest way is to pull the pan, look at the crank stroke 1st, then the bottom of the cylinders will have some grinding/clearancing for the longer stroke if it's 3.75". You can also tell the bore size that way as well, a touch harder than just looking at the top of the bore but the pistons are right there - measure the skirts. If the crank is GM, it will have casting number/date on it. Dates are letters/mubers EX: - B0779 - Feb 7th, 1979.
The "010" block was a high nickel block that was made for many years, early GM 350 targetmaster crate engines, and several 4bbl cars trucks. Only made in 4" bore thus 350 (or if someone messed with it 327, 302).

I'd pull the pan if it was me, if you have to see about returning it that way your only out a few $$ - and find a mechanic that knows something - everything you said he told you is BS.

Don

...If it is not as advertised ,verbal or otherwise , you can take him to small claims court ,and you WILL win , 25 bucks to file plus your time ,just my.02, DC:bowtie:

"he's asking $ 4,000.00 for it and it has over $ 8,000.00 in it"

That 350 better have a blower on it for 8K.

My 383 we ran in the dirt car has a tiny balancer like a early 327. Pull the pan.

Iv got my mechanic pulling the numbers off it today, so i can find out what it is. So its no way of this being a 305 i should be fine. If its a 302 , 327, or a 350 ill be ok with that atleast.

Iv got my mechanic pulling the numbers off it today, so i can find out what it is. So its no way of this being a 305 i should be fine. If its a 302 , 327, or a 350 ill be ok with that atleast.

Why are you paying a mechanic?

-- Joe

Why are you paying a mechanic?
BECAUSE HE HAS NO IDEA WHAT HE IS DOING..........

BECAUSE HE HAS NO IDEA WHAT HE IS DOING..........

Sounds like his mechanic doesn't either.

Hobby is not so much fun if your paying all kinds of money for stupid people to make the same mistakes, yet hide them.

-- Joe

Iv got my mechanic pulling the numbers off it today, so i can find out what it is. So its no way of this being a 305 i should be fine. If its a 302 , 327, or a 350 ill be ok with that atleast.

Since 302's are pretty rare, and the 327 hasn't been mfg'd since '69 it's a pretty good bet it's a 350 block. (the first 350's were made in '67) Until you check the stroke there's no telling what it is. lol
Don

Even aftermarket cranks have part numbers engraved on the main counterweight (my Scat has it on the first large counterweight). The crank will tell the story of whether it is a stroker or not. But whether it is a 377, 383, etc., you'd have to mic the bore or find the number on the top of the piston. I would definitely take the heads and pan off before installing the engine. Its easy, its quick and it does not cost a fortune. It would bug me to no end not knowing for sure.

Keep us informed!

Even aftermarket cranks have part numbers engraved on the main counterweight (my Scat has it on the first large counterweight). The crank will tell the story of whether it is a stroker or not. But whether it is a 377, 383, etc., you'd have to mic the bore or find the number on the top of the piston. I would definitely take the heads and pan off before installing the engine. Its easy, its quick and it does not cost a fortune. It would bug me to no end not knowing for sure.

Keep us informed!

My forged Ohio crankshaft doesn't have any markings at all. That is how all of their cranks leave.

Although probably not all that uncommon, it happens from time to time with some vendors.

http://www.ohiocrank.com/home.html

-- Joe

Actually I Work For A Dealership, And One Of The Mechanics Here, His Uncle Builds Drag Cars For A Living. So I Figured If This Guy Can Build All These Built Nova's And Chevelle's And Etc With These Huge Big Blocks, He Should Be Able To Do A Small Block. Iv Seen This Mechanics Work And He Does A Good Job. And He Is Only Charging Me A Small Amount Too Which Is Good. But Hearing Everyone On Here Is Making Me Question Him Also If He Knows What Hes Talking About.

Actually I Work For A Nissan Dealership, And One Of The Mechanics Here, His Uncle Builds Drag Cars For A Living. So I Figured If This Guy Can Build All These Built Nova's And Chevelle's And Etc With These Huge Big Blocks, He Should Be Able To Do A Small Block. Iv Seen This Mechanics Work And He Does A Good Job. And He Is Only Charging Me A Small Amount Too Which Is Good. But Hearing Everyone On Here Is Making Me Question Him Also If He Knows What Hes Talking About.

I believe you had caps lock on.

Actually I Work For A Nissan Dealership, And One Of The Mechanics Here, His Uncle Builds Drag Cars For A Living. So I Figured If This Guy Can Build All These Built Nova's And Chevelle's And Etc With These Huge Big Blocks, He Should Be Able To Do A Small Block. Iv Seen This Mechanics Work And He Does A Good Job. And He Is Only Charging Me A Small Amount Too Which Is Good. But Hearing Everyone On Here Is Making Me Question Him Also If He Knows What Hes Talking About.

Think about what you said.

You are hiring him, as a mechanic.

Yet you have "Seen his work".

If you are not a mechanic, how do you know what you have seen is right?

I've met a lot of mechanics over the years. Hell I owned a race shop for almost 10. The majority of people are idiots and you have to be careful. A guy who does brakes is not qualified to build race engines, heck he might not even be qualified to do brakes.

-- Joe

My forged Ohio crankshaft doesn't have any markings at all. That is how all of their cranks leave.

Although probably not all that uncommon, it happens from time to time with some vendors.

http://www.ohiocrank.com/home.html

-- Joe

I sit corrected. I guess I should have wrote, "Some aftermarket cranks have part numbers stamped in". I know my Scat does.

I sit corrected. I guess I should have wrote, "Some aftermarket cranks have part numbers stamped in". I know my Scat does.

Yeah. I think there is just soo many companies buying the chinese forgings that shops are not engraving numbers.

It can be a issue too because you don't end up knowing what forging you are getting, 5140, 4340, etc. And most of the chinese cranks I have seen, the parting lines were completely machined, so you have to whack the thing with a wrench to even tell if it's forged vs cast.

-- Joe

I figure for a $1,000, tear her down and do NO more than check it and if it check's out OK, go!

This way, you will know such crap as bearing clearances, what cam and piston type and heads/valve sizes along w/ enough info to calculate the CR right!!!!!!!!!

And I would be tickled to death to find a 1-piece seal later block that has the roller cam stuff ready to go but not used!

Hell, the last of the new crate Goodwrench 2-piece seal engines are now over $1500 if you can find one...

pdq67