It has been decked already before I got it. Bought a bunch of stuff from a guy that was moving to California a while back. If it is not exactly zero deck it is very close.

Thanks Cab. Any advice on piston choice is appreciated. The pistons mentioned are TRW #2355 .030 forged pistons. As heavy as they are I would think they should work but have not measured the thickness of the top. I also have on the shelf a set of KB 237 flat tops that are .040 over with very similar compression height.. I know the KB's could run a tighter clearance but don't know if they would stand up-especially with the top ring so high. The TRW's are old and would swell and require a lot of clearance.

What rings would you chose for this application?


Aren't there some 440 industrial motors that have the same type water pump and heads? Are the heads the same configuration as the 413-3 with a closed chamber and sodium valves?

I'm sure your six pack pistons have the standard 5/15,5/16, 3/16 ring pack piston grooves, make sure though , and then order a set of rings for a motor home motor in the proper bore size if your piston top are thick enough to use in that motor for your deal
The TRW should have the needed piston to cylinder wall clearances built into them, you might want to add another .0010 to be safe though
Take one of those pistons and measure it where you should on the skirts at room temps and then stick it in a preheated oven a little over 250F and remeasure it to see how much it grows at those temps. , be careful so you don't burn your fingers also
On the 440-3 motors they are no where near like the 361 and 413 industrial motors so don't count on finding any 440 or 440-3 motor with those early heads and water pump timing cover like those on the early, pre 1973 H.D. 361/413 motors.
As far as the 440-3 valves I'm not sure about them or how they where made

Doc or Cab, you guys wouldn't happen to have a 413-3 piston laying around somewhere would you? I'd like to get my hands on one and do some measuring. Thinking about a hemi rod option. Or maybe someone has info what the pin height on these pistons is?

You looking for the 413 industrial piston compression distance ? .... CD ??

I don’t have any of those motors here OR the specs but I’d bet my life you’d be totally safe with that rod using any type of 383 or 413 piston. But I’m also sure that you will need to do some major shaving the piston tops to get a good quench.

And you would HAVE TO adjust any of that based on the deck height of the block you wind up using.

And NO WAY would I use that industrial piston in this project. The dish in that piston is huge

Thanks Doc. I got these specs from a guy on ebay regarding the 413 motorhome cam. He has some NOS ones listed. Really surprised how little lift it has. Smaller that a 318 in that regard.

cam lift int .240" exh .240"

valve lift int .360" exh .360"

adv. dur. int 260 exh 260

effective timing event @.050" cam lift

dur. int 193 exh 194

opens int 10 ATC exh 27 BBC

closes int 23 ABC exh 13 BTC

overlap 44

lobe line int 106 exh 110

mG .., that cam I would trash too .... never really made any decision on a cam choice but the cam tech THESE DAYS has to be way waaaaay bester than late 60s !

Yes sir I totally agree.

Was looking at this baby Lunati but I am no cam expert.

https://www.lunatipower.com/voodoo-hydraulic-flat-tappet-chrysler-361-440-253-258.html

Hydraulic Flat Tappet. Very strong torque and increased HP for 383-440 cubic inch motors. Compatible with stock type fuel injection. Works great for pleasure/ski boats, and mild towing applications.; Advertised Duration (Int/Exh): 253/258; Duration @ .050 (Int/Exh): 208/213; Gross Valve Lift (Int/Exh): .454/.454; LSA/ICL: 112/108; Valve Lash (Int/Exh): Hyd/Hyd; RPM Range: idle-5000; Includes: Cam Only


I know what works in a street build but I admit to being out of my depth with the motorhome stuff.

But, I am learning thanks to you guys.

Me thimks you should look at a HEAVY TOWING APPLICATION.

I was going to suggest calling General Kinetics... but they were bought up by Lunati I believe. Maybe even try Racer Brown.

Used to have some dealings with GK many moons ago ... and they would grind up a special cam for a couple of $$ more