331/354 swap info

jsturtz · Post by **jsturtz** » Tue Jul 22, 2003 8:00 pm

I have the option to get a '54 331 with a pallet of spare parts. After IDing the "spares" they turned out to be heads, intake, and cross over from a '56 354. I am a Ford fan at heart but am not stupid enough to turn down a Hemi. It should look really cool in my '48 ford panel. My question is are the heads from the 354 compatable with the 331 and is it worth the trouble? I am building a daily driver and will keep most of it stock. (it comes with crome firepower valve covers) Any tips or info would be appreciated.

Post by **scottm** » Wed Jul 23, 2003 3:55 pm

The 331 and 354 are both low-deck blocks,
so I believe those heads should swap over.

jsturtz · Post by **jsturtz** » Wed Jul 23, 2003 9:53 pm

Thanks for that quick reply. I still have another project on blocks before I can start on the Hemi, but I need to make the decision to get this stuff before it walks. Any tips on building a good driver motor and are the 354 heads better ?

panic · Post by **panic** » Thu Jul 24, 2003 8:21 am

centerline · Post by **centerline** » Fri Jul 25, 2003 6:26 pm

The 56 heads will fit just fine on a 331 block. These heads use the water crossover with integral thermostat so you'll have to use a 55 or later intake manifold. The 54 and earlier had the thermostat housing in the manifold similar to a small block Chevy. These are the large port heads and should have the same size ports as the 54 and later 331 however; the combustion chambers may be slightly larger than the stock 331 heads resulting in slightly lower compression using stock pistons. The 331 only had 7.5/1 compression in 54 and a max of 8.5/1 in 55 so if I were you I'd pick up a set of stock 354 pistons when its time to rebuild and have it bored +.120 to 354 specs. Just make sure you have the block sonic checked first. 99% of all 331's can be safely overbored to 354. When I had my block checked it indicated that I happen to have one of the few that shifted just enough during casting to make it too close to take the chance so I went +.0625 (343 cu. in.) instead.

Good luck

TrWaters · Post by **TrWaters** » Fri Jul 25, 2003 9:15 pm

Actually, you would have to bore a 331 out .125 to reach the 354 bore size.

jsturtz · Post by **jsturtz** » Sat Jul 26, 2003 11:23 pm

I have the 56 354 intake with the 56 heads and water crossover, so I won't have any problem there. I was worried about the compression ratio if I put the 56 heads on. I haven't been able to find a listing of combustion camber cc's for either the 331 or 354 heads. Does anyone have these numbers? Also I have had a few nay sayers trying to convince me not to build the hemi because they are un-reliable and tend to have more than the average mechanical problems. I have also been told that while all the charts list the 54 331 with 4v carb at 235 hp that they don't get anywhere near that. I'm a pretty good mechanic and like a good challenge, but I like input from people who have actually seen, heard, and built this engine.

centerline · Post by **centerline** » Sun Jul 27, 2003 7:24 am

The early hemi is just as reliable as any other motor when it’s set up correctly. On the same line if you load it up with high performance racing parts it will be just as temperamental as any other race motor. Some of the problems come from people who run very high valve spring pressures, which causes a lot of wear on the rocker shafts.

Another problem is the availability of replacement parts when you're out on the road. However this is only shows up when you're running a motor equipped with the stock ignition system, starter and water pump. After all you just can't go to your local Pep Boys or Auto Zone and pick up a water pump for an early hemi. Chances are the guy behind the counter won't even know what you’re talking about since it won't be listed in his computer. To take care of this problem it's easier to run a readily available Chevy water pump, a 340 or similar small block Chrysler distributor and a trans adapter that uses the small block Chrysler starter.

I think the naysayers you're talking to are just jealous. And yes to go to 354 cu. in. you do have to go +.125. Thanks to Tr for correcting me.

TrWaters · Post by **TrWaters** » Mon Jul 28, 2003 8:40 pm

Just to expand on Centerline's comments, the early hemis are great engines. I would just be careful not to have it built by someone who likes to build every engine like a sbc.

TrWaters

jsturtz · Post by **jsturtz** » Wed Jul 30, 2003 10:12 pm

Thanks for the info. I build my own engines, and have never built a sbc, or any bbc for that matter. I will be back with more questions in about six months when I have started building my Hemi!

TheHEMI.com

331/354 swap info

331/354 swap info

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