M Block Build.

[Angelo Voltura]

Welp, as it usually happens, what was going to be a cam replacement turned into a "screw it lets build the sucker".

Gary, I know you are an M motor fan and I've been a fan of the underdog for a while now, so I'm thinking about what direction I want to go for my engine. I would really like your input along with anyone elses who has built one of these engines. I was originally just going to get it running so I could build my 429, but that can wait. I want to play with my M.

The 351 as it sits ran awesome, plenty of power and was quick for what it was in my 2wd. But, I want more. Basically this truck is going to be a back road bomber and stop light racer. The goal is to be able to smoke my pals (I already do this but I want to do better) and have something that's just fun to drive. The 351 is still bolted in the truck. I do not want to break that bank on this engine.

The run down on the current 351 is as follows:

.030 over w/ stock style pistons
Stock 2V heads with mild exhaust porting, double valve springs 260lb @ .510" lift
Currently non-adjustable valvetrain but have option to convert to full adjustable
218/228 @ .050"
114 LSA 109/119
.509/.509 lift
1 3/4" full length headers
Performer 400 intake
Edelbrock 1406 carb
Cloyes single roller timing chain
MSD 6AL w/ rebuilt Duraspark II distributor
Blaster 2 coil


I would say it was making a solid 300 fwhp when I lost the cam. However a few guys that I drag race with are saying at reality it was probably closer to 225 at the wheel, which is still a large upgrade from the 156 this engine had originally.

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Basically right now I have 3 choices. I have a bare bones block that is .040 over, that was a 400 at one point, it's now just a block. I also have the above listed 351 short block and a complete 400 that supposedly has 20k miles on the rebuild with flat tops in it. I can go any direction at this point. While I'm still thinking about slapping this 351 together so I can drive it, I'm likely going to build a 400.

My buddy who just built a 400 this past week that is supposedly to make 400hp and 500tq is telling me to ditch the 351 since after losing the cam we cannot verify the condition of the short block, and it has a nail-catching ring ridge and likely needs rings. Right now I'm really seriously considering saying screw it and yanking the short block and going with his 400 short block.

I am also looking at the same heads he used. They are the 72cc chamber Trick Flow 195cc heads. He is using TMeyer hyperuetectic flat tops that with this head yield 9.3:1 compression on pump gas. I'm not sure what pistons are currently in this 400 he's giving me. I'm hoping to go a little higher on compression and a nastier cam than the 218/228 I currently have.

Any suggestions before I pull the trigger?

[Gary Lewis]

I vote that you go with the 400 and the Trick Flow heads.  But you should go with 10.25 - 10.5:1 compression with the aluminum heads.  The aluminum cools the charge enough to lower the detonation point roughly 1 point.  So if you don't change to different pistons you are giving away power.

And I'd tap Tim for a cam.  He has grinds that he's used for years on these engines and with those heads.  He has them custom ground to what you want the engine to do.  

[Angelo Voltura]

What would I have to do for pistons to bump the compression? His website only offers 9.3:1 400 pistons with a 76cc chamber.

Be it I have enough parts here to get the 351 running I am probably going to put together so the truck is moveable and do the 400 on the side.

[Gary Lewis]

I'm pretty sure he has the pistons.  Call him.

[Angelo Voltura]

I think I will be. The other thing is I want to be mindful of how I put it together in case I decide on a power adder like boost or nitrous.