Acceptable Time Period for Date/Period Correct Engine

[RockyPat]

Hello all,

I have a 1973 Roadrunner that was built on 9/20/72.

It is a 400 4 Barrel/727 car.

The original 400 is missing.

I want to get a date/period correct 400.

I am looking at a 400 that was casted on 3/30/72. It was assembled on 4/18/72.

Is this too much of a time gap?

What is an appropriate time gap?

Also, since my Roadrunner was a 400 4 Barrel car, would the original 400 have come stamped with an "HP" on it?

Any help would be great!

Thank you!

 

[toolmanmike]

Too much in my book. A few weeks to a month gap is more comfortable. Rarely were they over a month old.

 

[WileERobby]

Here's my "2 cents" ( worth 2 bazooka bubble gums when I was a kid ): not matching number engine... 73 model... 400 engine... I wouldn't put too much effort on a closer date engine, if the price was right on that engine, I'd do that. I don't think a closer date engine would make that much of a difference. That's up to you of course, whatever floats yer boat. And, I for one, like your year bodystyle !

 

[RemCharger]

Here's my "2 cents" ( worth 2 bazooka bubble gums when I was a kid ): not matching number engine... 73 model... 400 engine... I wouldn't put too much effort on a closer date engine, if the price was right on that engine, I'd do that. I don't think a closer date engine would make that much of a difference. That's up to you of course, whatever floats yer boat. And, I for one, like your year bodystyle !

That makes sense. Even a 74 wouldn't draw too much stink eye.

 

[Lefty71]

Also, since my Roadrunner was a 400 4 Barrel car, would the original 400 have come stamped with an "HP" on it?

I don't think so.

 

[RockyPat]

Too much in my book. A few weeks to a month gap is more comfortable. Rarely were they over a month old.

Thank you.

I did not know that they were built so quickly after assembly. That is cool.

 

[RockyPat]

I don't think so.

Thank you Lefty.

 

[RockyPat]

Here's my "2 cents" ( worth 2 bazooka bubble gums when I was a kid ): not matching number engine... 73 model... 400 engine... I wouldn't put too much effort on a closer date engine, if the price was right on that engine, I'd do that. I don't think a closer date engine would make that much of a difference. That's up to you of course, whatever floats yer boat. And, I for one, like your year bodystyle !

Yes, I think you are 100% right. I like the motor and its price. Apparently, it ran before it was pulled, and it has been stored inside.

 

[eldubb440]

that 4/72 engine is most likely a 72....... but once the original is gone, does it really matter?

 

[RockyPat]

That makes sense. Even a 74 wouldn't draw too much stink eye.

Agreed. Thank you

 

[RockyPat]

that 4/72 engine is most likely a 72

You are right, it came out of a 72 Charger.

 

[Lefty71]

Thank you Lefty.

I'm hoping others will chime in here....I have and have-had lots of 400 big block Mopars, most all have had 4bbl carbs. I`ve seen quite a few RB blocks stamped HP and HP2, but i`m not sure i`ve ever seen HP stamped on a 400?

 

[RemCharger]

Pretty sure they did.

 

[WileERobby]

Yes, I think you are 100% right. I like the motor and its price. Apparently, it ran before it was pulled, and it has been stored inside.

I think what you just said is way more important than getting a closer build-date engine. Get that baby in there & get that runner runnin' !! Be sure to keep us abreast with your progress and, of course, the mandatory photos !

 

[MoparLeo]

Non matching numbers engine doesn't matter even if it was made the same day and shift. They are only original once.
After that it is just a pissing party....

 

[70rcode]

Chrysler didn't Always use engine blocks that quickly after block casting date....I Saw a factory built June '70 Cuda delivered to a dealership ( off the transporter) with a '69 cast dated HP stress relieved engine block.....There never seems a 100 % Mopar sure thing back in the good ole days !!

 

[gtx6970]

Use it, anything better / closer aint gonna squat in value or desirability

and ps, Ive never seen a HP stamped 400 that I can remember

 

[RockyPat]

I'm hoping others will chime in here....I have and have-had lots of 400 big block Mopars, most all have had 4bbl carbs. I`ve seen quite a few RB blocks stamped HP and HP2, but i`m not sure i`ve ever seen HP stamped on a 400?

Mine is a HP motor. It is a 400. I hope this helps.

 

[RockyPat]

Pretty sure they did.

You are right. They did.

 

[RockyPat]

I think what you just said is way more important than getting a closer build-date engine. Get that baby in there & get that runner runnin' !! Be sure to keep us abreast with your progress and, of course, the mandatory photos !

Thank you! I did end up purchasing the engine. The cylinder walls look to be in great shape. I am trying to keep it low budget, so I can get it into my car faster.