Printable View
I need help identifying a block. It is said to be a 400 pulled out of a 78 3/4 ton truck. But when I ran casting numbers it said 350. It is a 4 bolt.
BLOCK #:
3956618
ENGINE VIN #:
V0425WI
It would be great if you could tell me what motor this is. I beleive it is a 400 but i may be wrong.
Just look for the steam holes between the cylinders, if it has the heads off. If not, check the vibration damper for a balance weight, or the ring gear for a weight. The 400 is the only externally-balanced SBC.
According to morte, considered the bible of chevy casting numbers to some. It is a 1969 302, or 350, with the 4 bolt main caps. Link # 1 is the block casting #s. Link # 2 shows how to find the block casting date on your motor for the year it was made. The 2nd link is titled casting # locations, but also in the first paragraph it gives the date location along with the casting location.
casting #s
http://www.mortec.com/castnum.htm
casting date
http://www.mortec.com/location.htm
It had a factory q-jet on it if that matters. I will check the date code.
Casting number 3956618 was used for the following engine blocks: 1969 - 302 used in the Z28, 1969 – 327 used in full size, and 1969 – 350 cars and trucks.
V = Flint
04 = April
25 = 25th day
WI was used for 1967 – 283 used in 4 wheel drive trucks (K-10 to K-25), 1968 – 307 used in 4 wheel drive trucks (K-10 to K-25), and 1969 – 350 GMC ¾ and 1 ton pickups with 4 bolt mains.
My guess is that you have a 350 from a GMC pickup
Regards,
Glenn
Are those 350's externally balanced because I beleive that this motor is?
Are those 350's externally balanced because I beleive that this motor is?
Did they run bigger balancers/dampers back then??
only the 400 and 454 were externally balanced.
All small block Chevy's are internally balanced with the exception of the 400 which is externally balanced on the flex plate and also require a correct “harmonic balancer”. The 400 is the only small block that actually uses a harmonic balancer which, in conjunction with the flex plate or flywheel “balances” the engine. A more accurate description for this component on all other Chevy small blocks is a “harmonic damper” or “torsional vibration damper”.
454/502 Big Block Chevy engines also use an externally balanced crankshaft.
Regards,
Glenn
Additional information:
GM used different widths, different weights and different timing positions, for a combination of seven different dampers, depending on what the engine is used for. The 350 used four different ones –
Part Number 6272221 is 6-¾”
Part Number 6272222 is an 8”
Part Number 3947708 is also an 8” referred to as “Special High Performance” and no longer carried by Chevrolet dealers (also used on the 302 motor).
Part Number 364709 is an 8” and specified for “Off Rod Racing”
GM trucks used a 7-1/4” OD damper for 265-350 trucks, 409 (trucks) an the 194-292 Inline-6 cylinder
305CI times at 12:00 o’clock position
350CI times at 1:30 o’clock
When in doubt – bring number 1 piston to TDC an install the correct timing pointer.
The date number is
C198
or
C199
I bought this in the 80's. It was a 1978 3/4 ton pickup. The guy says it was a stock 400 But everything I look for says its a 69 350. It doesnt really matter but I would like to know. So if it was in 1978 the date number woul match up.
Casting Date Example: E038 - (E = Month, 03 = Day, 8 = Last digit of model year (1978)).
Month: A = Jan, B = Feb, C = Mar, D = Apr, E = May, F = Jun, G = July, H = Aug, I = Sep, J = Oct, K = Nov, L = Dec
Is it possible that the casting date is “C108” which would be March 10, 1978?
It might have been so do you guys think it is a 400 or 350 by the numebrs I have given you I think it might be a 400.
Look at the Balancer . If it Looks Like this you have a 400 SB . Also the 400 4-Bolt main Blocks had 3 Water Plugs . Some of the 400 2-Bolt Mains had 2 but had the Boss in the Casting were the 3rd would go . All and All if the casting # On the Back off that Block show's it to be a 4" Bore L/J that's what it is . Truck that year Had 4-bolt Blocks . Most had cast Cranks and the Weaker White Iron Caps .
Just measure the bore and stroke. The numbers don't always mean much without knowing the history of the block and what sort of work has been done to it or what parts were put into it.....
Yes that would be best Could be a 302 or even a 408 From that Block . http://www.popularhotrodding.com/tec...ock/index.html
The numbers thing can be terribly misleading, most anything could have been done over the years to the block and other components.... Very easy to check the bore and stroke before you dissassemble it. If it's just a bare block, then just measure the bore and probably also check the dimensions on the cam and crank journals....Who knows what's been done there??? If it's dimensionally what you want, then have it tanked and mag checked. Then build it....
On a street type engine, I don't really think it makes a whole heck of a lot of difference what the nickel content is, street use won't stress it much anyway...
Another consideration before you waste a lot of time searching for a block, then having it cleaned and checked, then all the machine work remember there are a number of companies along with the OEM manufacturer that offer brand new blocks that are superior to the production pieces.... No sense to spend a bunch of time and money, reject 3 or 4 blocks cuz someone has already been in there and mangled a few parts or performed some questionable machine shop practices, then spen all the money for maching everything when a brand new block can be had for under $2k..... Ask Pat or one of the other machinists what it costs to do a block up so that dimensionally it is equal to a new one.......
It's not always about how much $$$$ you spend, but how you spend it.....
Like you said for a Street Build up to 450 H.P a GM Block is Fine . If you are Going over that or Running Lot's of Nitrous / Boost . Then Buy the Dart or World Block . As for other SB Chevys being Externally Balanced . Yes the 1986 and Newer One Piece Seal 5.0-5.7 Engines Use a Counterweighted Flywheel / Flex Plate . But it's weight is much smaller then the 400's .
To quote from the Dart site:
"Dart's new Special High Performance (SHP) small-block meets the need for an affordable, precision-machined cast-iron block with superior features. Designed for high-performance and heavy-duty applications producing up to 600 horsepower, the SHP block is the ideal starting point for hot rodders, drag racers, circle track competitors, off-roaders, and high-performance marine enthusiasts." unquote
This is a new block, Mains #2, 3, 4 are 4 bolt with splayed caps... Dart retails it for $1500, seen it other places for a bit less.........
Guess it depends on what you're planning on building, but this looks like a heck of a deal for me... Think chebbie sells one in their catalog for even a bit less???????
Sure that's a Nice Block You can Build a 454 SB with one of them Blocks . I would Love to have one . But Even at that Great Price I have to Pass on it :( But I do have a Few 10/20 High Nic Tin 3970010 Blocks with the stronger caps and a Few sets of heads Laying around ? A 355 420 H.P Build will have to do for Know . But if I ever win it Big I will build Two of The Dart Blocks :LOL: They are Nice same as there Cylinder Heads are :)
Yeah I have found out now that it is a 400.
Thanks for all the help