Happy Easter All. I am in the process of making my '77 F100 with a 351M/400 into the beast she can be and have hit a point where I need some advice. My original cam shaft is about toast and know I need a new one. While I am having that done, I just a soon add some new aluminum heads to wake my truck up. What is the best value in the aluminum head game? Also, if anyone has any that they want to sell, I am in the market. Any help is greatly appreciated.

 

The Kaase CHI heads are probably the best.

Kaase C-400, CHI cylinder heads

Edelbrock and trick flow make heads as well. Probably depends on your application which ones are best. Full on race heads wont help low end torque in a truck, but any of these will be an improvement over stock.

Most important thing in these engines is getting the correct pistons to increase the compression ratio. To my knowledge, the only pistons that do are made by Kaase.

Other pistons will say they are flat tops, but they dont increase your compression ratio in any meaningful way.

If I'm wrong, someone can correct me.

Also try searching the engine forum for specifics such as this.

 

Depends what you are doing with it. If you are building a 2wd street/strip monster to crush imports and embarrass late model junk with 50 year old technology, then a set of early 351c closed chamber/big valve/huge port heads from an early mustang/cougar/cyclone can't be beat for the price. They are slightly doggish under 2500 from, but pull like a rocket through 7000 RPM. Pick a set up for about 500 bucks all day long. They are cast iron, but they are brutal. You'll need intake spacers to make the C intake work on the M, but the valve train/cam etc are identical. A 400 crank, some TMI flat tops, a big cam, a loose converter and 4:10s , you'd have a nasty fast truck for cheap.

If you are building something that needs to be quick, but streetable, the CHI 3v's are well reviewed. Aluminum, lightweight, good chambers, and perform well throughout. I wanted a set, but they are slightly pricey.

If you are looking for torque and affordability, Australian cast iron 2V Cleveland heads are the hot ticket to turn a 351m/400 into an absolute animal. Really wakes them up, straight bolt on. They are getting scarce though.

The edelbrock aluminum heads are pricey, but both the Cleveland and M guys say the performance gains over the stock 2V heads is amazing.

Stock M and Cleveland 2V heads flow better than most in stock form. Get em resurfaced for a bump in compression, mild porting, 1 piece valves, port match and they work pretty good for an all around duty head. I'm building a 400 with slightly reworked stock heads for a work truck right now, and the machinist is confident it's going to make about 400 HP and well over 450tq. We will see, from past experience, that's about close to right.

Thanks for building a 351M/400. We M motor guys take a lot of abuse and listen to a lot of lies, ignorance and misinformation about our engines. You will enjoy miles of trouble free dependability and gobs of nasty torque for cheap as I have. Good luck!

 

Any leads on some Aussie heads?

 

Australian heads are all over the place. Like on Ebay. Folks import them by the boatload. But then you have to have them gone through and that isn't cheap.
Procomp has come up in recent years and you can get a set of heads complete from them for less than $1200. Look under Speedmaster.com
There are others, look online for the selection.

R

 

There is a forum specifically for 351/400 engines on here. Lot's of info there. I don't remember needing spacers for my intake when I put 351 Cleveland heads on my 351M. Put an Edelbrock 4 barrel intake on it also. I bought a 351C engine for $100, yanked the heads and sold the block for $100. Machine shop rebuilt them for $500 including installing hardened valve seats. I didn't mill the heads, but that would've given a little more oomph to it.

 

You need the spacers to put 351C intake manifolds on 351M/400 blocks.

I hope the OP is working on a 400. 400 is much easier to fix than the 351M.

 

You dont need to use a 351c intake. Just use an aluminum intake for the 351M/400.

 

If it is a 351m it needs 400 guts to be worth a damn. I run aussie Cleveland heads on my 400 and make about 370 hp. Got them cheap from a friend though.

I am building a 460 for my other truck and picked up some speedmaster heads. Quality is actually pretty good. Need a little bowl blend but pretty good for the $$$

 

It's been awhile, I forgot about that on the spacers. I actually traded a crank for a 400 dual plane intake for my 351M. It was a direct fit.

 

You can use a factory's 351M400 or an aluminum 351M/400 intake on factory 351M, 400, 351C, and Aussie 2V heads, it's a direct fit.

If you use the 351 4V heads, you will need to use a 351 4V intake with spacers, because the 4V's intake ports are a full 3/4 inch bigger than the 2v's!