413 swap

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vcustoms86

vcustoms86

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Im taking a 413 out of a late 60's motor home and swaping into my 71 dart. If i change the motor mounts for now will the k-member hold up to the additional eight and power? My goal for now is to just get it running. I know once its running and i try to make it go faster i will need to swap in something stronger but for now will the slant 6 k-member work?
 
There's no strength difference in the k-members, but any 413 built after 1965 will have a completely undesirable top end and water pump housing.
 
Jim Lusk said:
There's no strength difference in the k-members, but any 413 built after 1965 will have a completely undesirable top end and water pump housing.
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Whats undesirable about them? I picked it up for 100 bucks and it runs pretty smooth. Figured why not.
 
I think you'd be better off with a 440 block if you want to go rb block. More cubes. Theres no real advantage to running a 413 unless it has max wedge heads. There nothing undesireable,thier just down on cubes from a 440. On the plus side it should have a forged crank.

You coulld stroke it like a 440 though...
 
Like i said for 100 bucks i couldnt pass it up. I can probably get the car running and street legal for about 2 grand. Well, i hope anyway lol
 
needsaresto said:
I think you'd be better off with a 440 block if you want to go rb block. More cubes. Theres no real advantage to running a 413 unless it has max wedge heads. There nothing undesireable,thier just down on cubes from a 440. On the plus side it should have a forged crank.

You coulld stroke it like a 440 though...
Click to expand...

You might want to revisit the undesirable comment. Motorhome 413s has different heads (they look more like Pontiac heads than Mopar heads) and a HUGE water pump housing that also bolts to the front of the heads. Those parts are considerably heavier than normal passenger car parts.
 
I understand that if i had a 440 it would be best but I dont. There is no way i could find a running 440 with under 50k miles for 100 bucks. This is a budget build so im just gonna make the best out of it and see what happens. All i was looking for was advice on what the best way to do things with what i got and what problems im gonna run into with mounts and etc. Instead i got everyone telling me to get a different motor. Not alot of help guys. I just want to get it running.
 
I understand Jim but the undesireable parts are easily swapped out. The block is the main thing right? If it's in good condition why not run some more modern 452 heads etc and swap in a car wp? Easy enough.
 
The k member should be good with aftermarket mounts. For a 100$ u can't go wrong and like stated above you van always swap stuff out later. Bolt it in and Hammer Down!!
 
yeah sounds like a deal to me! I would just put a passenger car h2o pump on it..
 
Direct answer is yes. The K-Frame will hold up to the 413 and there's not much it won't hold up to. Once you get that 413 up into the 500Hp-600Hp (or more) range you'll find that the K-Frame will still be strong enough.
 
Where would be a good place to start looking for the mounts? Should i use the 727 with the motor or try and find a different one?
 
Engineswaps.com or google search trans adapt. I'm new the Mopar scene but I've learned alot on this forum from good people willing to share there knowledge. The search engine is your best friend too. Just got my 440 duster going and thanks to alot of good people on this forum.
 
The 413 used in Motor Homes is a 413-3 HD truck engine. The cylinder heads are unique on this engine and require special exhaust manifolds that will not clear any passenger car K-member. These heads will not accept any other manifold or header, the exhaust bolt pattern is different to any passenger car or later truck or motor home (440) engine. The water pump and housing are also different (6 bolt pump with greasable bearing). The short block should be usable, but these engines had lower compression than passenger car 413's, also check the crank flange, some of them are 8 bolt. The 727 trans is likely to be a short version with a bolt on flange, not a slip yoke.

Whether you choose to use this engine or not is up to you, just be aware that it's not easy.
 
I had one of these rebuilt to a 426 (.060 over 413). I'd slap the 452 heads on it, change the cam and run a car water pump. Torque monster. For $100, you are out NOTHING. I'd have bought it to before the guy changed his mind.

Yea..I traded this good engine for a 440 that turned out to be pure junk. Guy would not make good on it. He put it in a Dart. I hope that 413 blows to smithereens. He talked me out of that 413 cause he said I'd have to change so much over. Bullsh**. I was younger then and did'nt know any better. Live and learn.

Changing heads and a water pump really isn't that big of a deal.
 
Ajp440 said:
The k member should be good with aftermarket mounts. For a 100$ u can't go wrong and like stated above you van always swap stuff out later. Bolt it in and Hammer Down!!
Click to expand...


Yep..
Some people throw additional welds on the k frame but most of the time, it's really just overkill. Unless you are running obscene amounts of power and torque, fear not for the stock k member is more than plenty strong.
 
Your K-frame will be fine, Put in some Schumacker motor mounts for $160, Go with the 413 and some fun. You will need a different drive shaft. Down the road you will have to change the /6 rear axle. You a can keep the torsion bars for good weight transfer, it will not handle real good on turns.
 
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