I mentioned in another thread that the 330 engine is dead in my 67 Vista Cruiser, I am going to put a 78 403 in the car while I rebuild the 330. Is this going to be a direct bolt in with no major issues? Different water pumps or oil pans I can handle but will my front accessories line up (p/s, a/c) ? Any other issues? The engine is out of a 78 Trans Am. Are the motor mounts the same?

 

Use the 330 motor mounts. Use water pump and all pulleys and accessories off of the 330. Oil pan, I believe, is also the same.

 

X2 ^^^... flex plate bolt pattern is different.

 

I have the 403 flex plate, hopefully it will be ok.

 

I swapped mine from 330 to 403, easy swap, even easier if you use all ancillaries from 330 on the 403. I did a manual swap at the same time so I can’t say for sure but the torque converter should bolt to the 403 flex plate.


this is the 403

 

Existing converter to 403 flex plate will work, 330 flex plate to 403 crankshaft won't work due to a different crank bolt pattern.

Use the 403 plate as Toocool mentioned and it will work.
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OK, a new (possible) issue. The balancer (harmonic damper) on the 403 is 1 inch thick, the one on the 330 is about 5/8s thick. Are they interchangeable, it looks like it will make the pulleys out of alignment? I have a/c and absolutely have to keep it. What can I do here?

 

I used 403 balancer with 330 pulleys

 

The pulley mounting face is in the same place on all second-gen Olds balancers. The added thickness is towards the block, not towards the pulleys.

 

You dont know what a relief that is to hear. I have the 403 running on a run stand and was feeling pretty good about it until I noticed this difference, now I feel a lot better. The engine has been sitting for several years but started right up after I pre oiled it and put a good carb on it, then the core plugs started leaking, 3 of them rusted the centers out, Im going to replace them all before I put it in. Thanks guys.

 

Might be worth freeing up the 2 block drains on the 403 while accessible on the stand and replacing the frost/core plugs.

 

It would also be a good idea to flush the block while it's on the stand.

 

I Have all the core plugs out now and have flushed the block throughly, nothing but clear water now.
thanks

 

Well, im doing the swap tomorrow, I hope everything goes well. The new (replacement) engine has an Edelbrock intake, I hope everything bolts up correctly. I know the 403 runs and I will need to use the water pump that is on the engine in the car but I dont see any other issues off hand.

 

Wow what a difference. I knew the 330 in the car was tired but this 403 makes it feel like a different car. Way more power, very responsive and best of all I can use regular gas. I also added a HEI distributer at the same time. The 330 always needed premium. The 330 was rated at 320hp, the 403 is rated at 185. I know they were rated differently back then but that's just ridiculous.

 

That's great!

 

It's how they were rated. The 330 was rated at the flywheel with no accessories, where the 403 was rated at the tire in the vehicle. It's a massive difference for sure.
Even if the 330 did make more HP, the 403 should make more torque down low and that will make things feel quicker.