Flywheel and motor mount questions.

[YuriOrlov]

Hi, I have a 348/409 engine that I took out of a dually truck (it had been put in after market), it has a stick shift right now, I'm thinking about puting it in this other truck I have, so here are my questions: My other truck has a 305 sbc and a 700R4 tranny, will the flex plate on a 305 bolt up to a 348/409? And are the motor mounts in the same place? In other words is it a direct bolt in swap?

If it is, then I need to find a cheap alternator bracket to put my new high output alternator on the 348/409. Who sells those?

Thanks.

[jwhotrod]

Well, I'll tell you what I know. I dropped a 409 in a 35 chevy 2 door sedan that had been setup for a small block, and a 700r4. The motor will set in the same postion using the 305 motor mounts, and you can bolt the 700r4 to it and use a 168 tooth flexplate. However, you will find that the flange OD on your motors crankshaft will not fit into the stamped recess in that flex plate. So you need (2) .020 shimsto sace the flexplate back, you can get them from showcars.com Really inexpense, so to that extent it is a bolt in swap. Carb linkage, etc. is a different matter based on what you have obviously.

I also think there is some difference in block bellhousing bolt pattern depending on year of manufacture. Older blocks are different than newer stuff, I think.

I do know for sure the above is true for a 1964 block, someone else will be adding to what i have said here, this place is great for info and sharing.

[YuriOrlov]

Thanks. Is there a place to buy the correct flexplate? I'm not to keen on shimming the flexplate.
I know I could just look at my engine to see if the bellhousing is standard, but my engine is at my shop 80 miles away and I'm just throwing around ideas. I'll look more closly, and also see if infact I have a 409 or a 348, either way though, I was doing burn outs with it in a 1.25 ton dump truck! It's gotta be big horse power!

Thanks for the info.

[jwhotrod]

Actually if you want a new flexplate you can get the flexplate and shims from showcars as a "kit", but no matter what you do you will have to shim the flexplate. the OD of the bolt flange on the 409/348 crank is slightly larger than the flange on a big block or small block. the only option is to turn a chamfer on the crank flange, but do not try to do that chucking it up in a lathe and oing it correctly. This does not have any significant effect on starters or head space for the torque convertor.

[models916]

You can just grind a little off the crank flange to fit the modern flywheels.