351m or 351w?

[wannabebuilder]

tell me what you think is better and if you have ever built one because i have both and am asking for some tips on what to do. if i should build the one or the other. i am pretty new at engine building and could use some help.

[CobraEd]

I think that the 351M is a later derivitive of the Cleveland, but with more low performance components. There is also a 400M of the same block. I think most of the M engines may heve been low rpm and truck engines. Anyway there are TONS of really nice high performance aftermarket parts for the Windsor.

[blykins]

Between the two....Windsor...without a doubt.

[flwolfman]

Go with the Windsor, great aftermarket parts. The M can be made to run, but it is harder and more expensive to do so. The 351M is a smog motor for large cars and pickups. The 351W is the standard for today. Good luck with your build.

[lovehamr]

I concur, build the W. The M is a high deck version of the Cleveland with some rather morphadite features like mostly small block measurements but with a 429/460 bell housing bolt pattern. The 351 and 400ci engines were identical except for the rotating internals; i.e., different crank, pistons etc. It's worth noting that 4V Cleveland heads will bolt to this block and intake spacers are available to make that work. 400+ci with those heads could be a running machine. I still have to go with the others on the W though as the aftermarket (including Ford) has really stepped up to the plate with those engines and it'd be much easier.

Steve

[Jac Mac]

If your building a low budget motor and want to play a little here is a combo that works for a 351w.

Use the 351m rods (6.58"), modify as follows- Narrow the big end to the 351w width( these rods use 351c brgs, not 351w-same journal dia,different tunnel dia)- Fit pin bush's from 272/292/312 Y block( they press straight in)hone to suit the new piston pin size-Use pistons originally intended for 3.25" stroker 302w ( 1.165" comp height ). You will now have a rod ratio in the 1.89/1 area, still at 351ci but it helps move the torque up the RPM range,Make sure you rebalance, Tell your cam vendor what you have done when you order the cam, if he says it wont make a difference find another cam vendor.

Jac Mac

[Jim Barnett]

I'd trade 'em both for a 351 Cleveland, but that's just 'cause I've got one in my LAE and it looks and performs GREAT!! IMO) Otherwise, the W is the most preferred/used SB in many Cobras.

[cobrabobby]

I put a 400 with 4V CC heads in a Midstates and built it to run. They can make
great HP if built right but I wouldn't do it again. Not worth the hassles
associated with a bastard set up. Ended up being more expensive than
the worth of it. Go with a W or a straight C. Being different has its price!
Bob T.