[WANTED] 72 340 warranty block

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RRman68

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I would like to find a 72 warranty block for my 72 demon or a build date close to 01/31/72 which is my car build date.
 
I got a 12-31-72 440 on the way to the machine shop...lol if I don't get a title back on the 72 Duster I will check the block on it. I will keep an eye out as 340s end up in the shop from time to time.
 
I have a standard bore 340 standard 9.56 deck height out of a 1971 Demon. It is a 340-1 block one of the most sought after do to its strength for stroker install. most are 340-5 to 340 -8. Plagued with porosity and cyl not being concentric.

It is not the year. It is the -1 after the casted 340 left side behind the starter. 340-1 . I have had many 340's machined you can see the quality difference in the block due to no mold imperfections on the -1's. Especially in the right rear lifter bore and rear of block. -1's are first pour and quality scrutinized. Will sell if interested.

Some info you should take into consideration when purchacing a block if date code is preference. the lower the number after the 340 the better chances you have of getting a solid foundation. also demand to know the deck height many are cut to far over the years
 
If you have a build date of 1/72 then the casting date on your motor should be somewhere in the 4th quarter of 71......Keep it consistent with the factory logistics of supply line available to keep the production line running. I have a 71 or 72 340 in a 69 Barracuda I am going to swap out in the near future for a shiny 360 stroker that is sitting on an engine stand eager to be commissioned. The motor runs and the car has been driven by our family for the past 5 years. I will send you the casting information tomorrow.
 
If you have a build date of 1/72 then the casting date on your motor should be somewhere in the 4th quarter of 71......Keep it consistent with the factory logistics of supply line available to keep the production line running.



x2. You should be looking for a late summer '71 casting date if the assembly went into a car in January.
 
I have a warranty 340, the rivit and very top of the plate is still there, no vin stamped on the rail. But I think the date is 1/23/71 much to early for your build.
 
Thanks everyone for the info. I'm confused about the date thing, I get the original motor date should be late 71 but I assume that a warranted motor would be replaced some time after the car was sold and maybe blown up or whatever. ? So wouldn't the replacement motor(block) be dated after the car build date? Thanks
 
This has always puzzled me. If you don't have the numbers matching block, what does it matter which year your replacement block is? Once you lose the numbers matching block, it's game over as far as any increase in value goes. Just put an injected 360Magnum or 408 stroker in it and enjoy the car.
 
Oldmanmopar just a question.. wasn't the -1 and through the span of that -4 and -5 the core shift? A realignment of the core to get it back to acceptable tolerances? If that's the case wouldn't the first batch of -2 be tighter than the last ones of the 1? Just trying to not over hype the stamped numbers. I'm learning and there's a lot to learn!
Dale
 
Thanks everyone for the info. I'm confused about the date thing, I get the original motor date should be late 71 but I assume that a warranted motor would be replaced some time after the car was sold and maybe blown up or whatever. ? So wouldn't the replacement motor(block) be dated after the car build date? Thanks

The cast date and build date on the block are two different things the actual engine build up date ( when the short block was assembled with Pistons rods etc..)with a lot of the engine details are on the drivers side front just under the head. My demon was built on April 2nd 71, but the block was cast 7/7/70 it was assembled 11/23/70 but not put into the car for another 4.5 months on April 2 1971,

Most engines were cast 2 to 3 months before the car build date, and usually the engine build date will be anywhere from a week to a month before the cars SPD. But with mopar there are exceptions.
 
Oldmanmopar just a question.. wasn't the -1 and through the span of that -4 and -5 the core shift? A realignment of the core to get it back to acceptable tolerances? If that's the case wouldn't the first batch of -2 be tighter than the last ones of the 1? Just trying to not over hype the stamped numbers. I'm learning and there's a lot to learn!
Dale

What I have found 1's and 2's are near perfect when sonic tested. Quality control personel on any pore usually checks the first two molds at the begining of the shift when they are being made.

I know this ffrst hand I worked at a foundry.

Usually at the end of the shift those making the molds were watching the clock to go home . Also the molds were still a bit damp. also quality control is gone for the day on long coffe breaks. You know how it is, Pride is always there at the start of a shift and disapears as the shift goes on.

The same goes for X blocks I have had them with real bad porosity. worse then stardard blocks. I believe it is due to High nickle content. Higher temp with damp mold.

Now this info is only what I have gathered myself over the years of owning and building many 340 motors. I saved many blocks over the years most all were low number or race blocks.

I had a -6 block throw #5 piston out of the block coming off the turn in a sprint car.. When you looked at the motor everything was gone around that piston. all that was left were the head bolts and part of the block bolted to the destroyed pan rail . It looked like it had a missing tooth.
 
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