355 motor 348 motor interchange

The rear motor mount set up is guite a bit different between the two. The head transfer would be difficult also. There has been discusion before on this board about it. The oil gallies/drainback is different 3 vs. 2. Anything can be done but was the end result worth it? That would be a matter of opinion. IMO you would be better off to buy a 348 and enjoy it for what it is or buy a 355 and enjoy it for what it is, both are great cars for different reasons. Combining the two seems useless IMO. The only interchangable parts that I'm aware of are the cyl. liners, probably are other minor parts, I have not that thorough of search. Regards, Vern

 

I am currently rebuilding my 348 gearbox with some internals from a 355. So some of the parts are interchangeable.

 

Fchatter Andy Hls has the 355's 6 speed on his 348 with 348 motor. He's got a thread on the conversion (http://www.ferrarichat.com/forum/showthread.php?t=46657) as he had to make slight changes (new brackets for the rear of the subframe) to make it work...but his 348 crank did bolt up to the 355's 6 speed so I'd presume that in reverse that the 355 engine would bolt to the 348 tranny likewise.


But heads on a 5 valve per cylinder engine matching with a 4 valve per cylinder engine?!

 

For the amount of money it would take to do it properly you're better off just buying a 355.

 

Oh? What internals??????

 

Ernie, I disagree a bit. If you could get the bracket design and any other changes from Andy Hls, who pioneered the mod, then going to a used 355 tranny on a 348 engine after you've blown your own tranny might not be that much different in price.

As a Spider owner, I don't **want** the maintenance hassles of the 355 power top hydraulics, motor, ECU, etc. I don't want the power steering pump, belt, and hydraulic issues, either. I don't even want the adjustable shock ECU/motor hassle. I don't want the 355's power seats.

But the 355's 6 speed tranny is pretty cool. The extra horsepower in the 355's motor is likewise appealing.

 

I can see why Andy did the swap, and he was able to do it with some mods. However I don't think it would be as easy to do the engine swap. yes it will bolt up to the 348 tranny but that is the easy part. Especially if you put the 5.2 engine in. Not only would you need the engine, you would need the ecu and the wiring harness too. Plus the location of the oiling system. The 348's have the tank in the rear, were the 355's have the oil tank on the front. So the plumming for that would need to be changed also. Then there is the issue of the a/c system. The 348 has the alternator on the left side of the engine and the a/c pump on the right side. The 355 has them flip flopped. So unless you are planning on not have a/c you would also have to change the plumming for the a/c.

With the way 355 prices are coming down, to me it makes more financial sence to spend an extra $10k - $15k for a early model 355, that already has everything done. Yes the 348 and the 355 share the same body, but why go to all the trouble. If you what 355 performance why spend the time, money, headaches, busted knuckles, etcetera, changing a 348 into a 355, just get a 355 in the first place. Or if it's because you like the look of the 348 better, then spend the money on making your 348 a little bit quicker. Justin's 348 spider puts out 365hp and he recently maxed it out at 186mph! That is only 10hp less than a '99 355 and the same topend.

 

Now that I agree with, Ernie.

But, if your tranny was already blown and a used 355 6 speed was handy, I'd think that with a little Andy Hls experience you could make the swap/upgrade cost effective.

Likewise, a blown 348 motor would be a good time to upgrade to a used 355 motor (even with the plumbing issues).

Although I agree with you that just to do one or both of the upgrades out of the blue would be a bit cost/effort prohibitive.