A friend of mine has a 1973 Dodge 318 motor. H asked me do I want it. I was thinking of building one anyways and was loking to see if Dodge changed anything on the motors and couldn't find anything. The question is I have a 318 in my truck no and if I would build the 73 from the ground up would it bolt in. The heads don't look the same as what I have on my truck. Any body have any ideas?
If it fits I want to build the motor to get 400 horsepower out of it.

 

Yours is fuel injected, his is carb'ed. You'd have to swap in a bunch of wiring and all that computer crap.

 

I was hoping the block it self would bolt in. IM going to change the carb out for fuel injection. I want to go with a roller set up and gear drive

 

there is proablly no difference in the block.........the only reason that i would use that old block is if it's four bolt main and the one in ur truck is 2.....but i don't know which is which.........i just say so hypotheticly..........look at it this way........if the block is useable.... like you said the heads are different so your truck is going to be down while you remove the engine change stuff over......unless the old block is better for some reason i'd leave it alone because your already gona have so much time in the changer over using your short block won't take that much longer and you'll proablly save your self a little headache

 

LA versus Magnum

The block itself has few important changes. Your heads are FAR superior though. You could build up the shortblock and slap your heads on it, as well as a Magnum style intake manifold. Check your heads for cracks though. I'd recommend getting the block, building it with high compression bits, balancing it, and slapping on some Magnum heavy duty heads.

 

Im going to use the old block and have it built. First step im doing is sending it out to the speed sho to do a little work. Then im ordering a kit from Summit. Pistion's and Crank gaskets and bearing. After that I will find set of heads from the junk yard and send them out when they come back I will start setting it up to be a roller motor with a gear drive. If I did my math right im looking at at lease 45o to 500 horsepower when im done. I want to have the new motor ready to drop in before next summer. The biggest problem is my wife because right now it's in the basement and shes flipping out. Lucky the truck won't fit LOL thanks for the help guys

 

With the amount you're going to spend getting those heads to flow you might as well look into getting aftermarket stuff. The 88+ (iirc) heads have a swirl port design, but the 318 heads seem to have small ports and you may need to really hog them out to get decent numbers from them. The HD Magnum heads flow really well right out of the box and they're not too expensive either.

I think you're overly optimistic on your target numbers, unless you're planning on going high compression stroker or forced induction. Even then it's going to be quite expensive to build and it may not be all that streetable afterwards.

 

+1 horatio, i agree.

 

I want power. I maybe a little crazy and I know it but when im done I want the power i need when I need it.

 

A 318 hogged out with a 4" stroker crank is just shy of 400 cid. You'll get about 20 cid more by starting with a 360 block, as well as larger crank bearings.

If you aren't going to stroke it though, and you do the supporting changes to get into the 450-500hp range, you're going to wind up with a motor that idles at 1500 rpm and won't really run well in conditions other than WOT. It's not going to be a good motor for your 4200+ pound 4x4 at all.