Engine Rebuild Kit - Ford Forums

10-24-2003, 20:18

Hey guys & gals,

Soooo.. Heh.. Had something funny happen today with my '77. See, I know that I've been having power/hp issues with my 351M, so I asked a buddy of mine who runs dirt track to take a look at it. He listened for a few minutes and then says I've got a miss. Turns out I had 4 dead cylinders. 2 wires were crossed on my distributor. Who'da thunk. Fixed that and man did that do wonders, as I am sure you can guess. Anyway I was all smiles. So to the question.

I was looking at a rebuild kit in my new Summit Cat and noticed a few things. The rebuild kit that I was looking at is the Fel-pro Sealed Power kit. The engine in my truck is the 351M/400 block. The only listing is for the 400 forged 8.33:1 comp 72cc Head. Now there is also a listing for a 351W Hypereutectic 9.17:1 comp 63cc Head. I know that more compression is a good thing, and I think that less cc's are good too (or am I wrong?) So I was wondering if I could use the Hypereutectic kit for my engine. Also what exactly is Hypereutectic and why does it get more compression? Anyway if anyone could point me in the right direction it would be appreciated.

About the heads, the 400 has 2v heads stock, but I haven't seen anyplace to get 4v heads for it. Are they not made? Wouldn't 4v heads be better? I assume that I would need a 4bbl intake and carb for it, or am I wrong?

TIA,

Aaron

10-24-2003, 20:23

Also, Would the rims from a newer model Ford Truck (say a lightning or a LaRouche) fit on a early model Truck like mine ('77)? Like the Lug patterns.

89F150 · 10-24-2003, 20:42

Ive read that it can be done. If you get a set of first gen lightning rims because they wer 5 bolt lug pattern. I'm guessing you have the five as well.

'92BigBronco · 10-24-2003, 21:12

Quote:

Originally Posted by 1bad77

Hey guys & gals,

Soooo.. Heh.. Had something funny happen today with my '77. See, I know that I've been having power/hp issues with my 351M, so I asked a buddy of mine who runs dirt track to take a look at it. He listened for a few minutes and then says I've got a miss. Turns out I had 4 dead cylinders. 2 wires were crossed on my distributor. Who'da thunk. Fixed that and man did that do wonders, as I am sure you can guess. Anyway I was all smiles. So to the question.

I was looking at a rebuild kit in my new Summit Cat and noticed a few things. The rebuild kit that I was looking at is the Fel-pro Sealed Power kit. The engine in my truck is the 351M/400 block. The only listing is for the 400 forged 8.33:1 comp 72cc Head. Now there is also a listing for a 351W Hypereutectic 9.17:1 comp 63cc Head. I know that more compression is a good thing, and I think that less cc's are good too (or am I wrong?) So I was wondering if I could use the Hypereutectic kit for my engine. Also what exactly is Hypereutectic and why does it get more compression? Anyway if anyone could point me in the right direction it would be appreciated.

About the heads, the 400 has 2v heads stock, but I haven't seen anyplace to get 4v heads for it. Are they not made? Wouldn't 4v heads be better? I assume that I would need a 4bbl intake and carb for it, or am I wrong?

TIA,

Aaron

I'm no where near an expert on the M-blocks but I do have some basic knowledge that may help you out. The 351M/400 and the 351C are both 335 series engines. Heads for a 351W will not bolt on and as far as I know, only the 351C has 4V heads available. I believe the 351C heads will bolt onto a 351M block. As far as 4V heads being better than 2V heads....I'll say that depends on what your plans are. 4V heads have larger ports resulting in increased volumes and slower air velocities through the ports when compared to the 2V heads. The 4V heads will generate more power on the top end than the 2V heads will but will not produce as much bottom end torque. If I were going to choose between 2V and 4V heads, I would go with a set of ported and polished 2V heads to get good torque on the bottom end and good flow for top end power.

Regarding compression, higher compression creates more power but higher octane fuel is required to prevent knock. The higher the dynamic compression ratio, the higher the octane rating required. Cam selection has a big effect on what compression ratio you will actually be running at as valve overlap and duration greatly effect the DCR. The smaller the combustion chamber size, the higher the compression ratio. Static compression ratio is simply the volume of the cylinder at BDC divided by the volume of the cylinder at TDC. Obviously, if you have a smaller volume at TDC, the compression ratio will be higher when compared to a cylinder head with larger combustion chambers.

Whenever you decide to rebuild, you need to think about what you actually hope to achieve. Options from mild to wild are available but wild usually costs a good deal more than mild.

Like the saying goes....

Horsepower costs money. How fast do you want to go??

351w · 10-24-2003, 21:46

Quote:

Originally Posted by '92BigBronco

I'm no where near an expert.
Heads for a 351W will not bolt on and as far as I know, only the 351C has 4V heads available.

there are 4V heads on alot of 351w's .
yes everyones opinion on the heads vary's depending on what they are looking to get out of them.
i have replaced my set of 4V heads with a set of aftermarket heads that flowed 2 1/2 times more than the 4V before i ported them. (go figure)
the 4V heads will work fine on any street driven vehicle but they tend to have a restrictive exhaust port if you want real power at top end.

i also run hypereutectic pistons and feel they are worth the money !

the makes of pistons are as follows.
cast are the cheapest.
hypereutectic are alot better.
forged is the ultimate high.

forged are mainly for a racing type application but can be used.
the reason the hyper's have a higher compression is merely the dome design of the piston and they come in different design.

whoever you order your parts from will be able to help you determine what the approximate compression will be but higher is not always better as 92 stated before.
try to stay between 9 and 9.5 compression and around 9 is probably better in the long run.

'92BigBronco · 10-24-2003, 21:54

Quote:

Originally Posted by 351w

there are 4V heads on alot of 351w's .

You're right. I was referring to the 335 series engine family not the Windsor's. I guess I should have made it more clear by saying that of the 335 series engine's, only the Cleveland blocks came with optional 4V heads.

10-25-2003, 05:03

Wow, that's alot to chew on; thanks for the info. My main goal is to make it as fast as possible, but street legal too. I guess my main goal is to get a respectable amount of HP out of it.

I think I'll stay with the 2v heads, and port and polish them, and buy my pistons seperate.

Here is an HP tip that my dirt track bud told me, anyone else heard this? If you drill 6 holes evenly around the TOP of the piston (about 3/32 or so) it increases HP in large, crazy amounts. The theory being that it changes the way the fuel is dispersed and compressed or something. The only thing I can't figure is I thought the fuel was ignited at the BOTTOM of the piston. Anyone heard this?

Anyway, thanks again for the info.

Aaron

'92BigBronco · 10-25-2003, 12:44

That's a new one on me.....and I don't think I would want to be drilling into my new pistons to find out. I guess it COULD promote fuel atomization by creating turbulence in the combustion chamber as the air enters the cylinder. Interesting thought......

The fuel/air mixture is usually ignited right around top dead center depending on your ignition timing. The flame front burns evenly (in microseconds) from where the spark plug ignited it towards the piston as it is forced downward by the force of the combustion on the power stroke. If the fuel/air mixture was ignited when the piston was at BDC, the force of the combustion wouldn't allow the piston back up to TDC for the exhaust stroke.

When air is compressed, it generates heat (PV=RT) and the higher the compression ratio, the more heat the compression stroke generates. If the compression ratio is too high and the octane rating of the fuel too low, the temperatures inside the cylinder will reach the auto-ignition temp of the fuel and will cause it to spontaneously combust. (Like a diesel engine) The higher the compression ratio, the higher the octane rating required to prevent this (knock) from happening.

Higher octane fuels burn slower than fuels with a lower octane rating, allowing one with a high compression engine to advance the ignition timing without getting audible knock. On the power stroke, the fuel burns and forces the piston downward. The slower the burn, the more work will be generated [work=(Force)(time)] which is why a higher compression engine creates more power, ceteris paribus. The piston being forced downward is subject to a larger force over a longer period of time....creating MORE POWER!!

Sorry if that's more info than you wanted but engine design and power/efficiency analysis is kind of my hobby. (no laughing allowed) :-)

351w · 10-25-2003, 13:27

hey 92, i think you need a girlfriend or another hobby !
then maybe it wont take me 20 min to read your posts.
haha.
1bad77 i think you need to find out more about the holes in the pistons because i have seen something about that once before but before i would consider it being lagit i need to hear more details about it.
i remember seeing a pic of a piston that had holes around the outer edge but cant remember any details if any were givin.
what you described earlier sounded a bit like how a 2 stroke would work being that the air/fuel mix is drawn into the cylinder on the bottom of the piston and then pushed up to the top through a transfer port in the cylinder wall before ignition.
but that is totally diff than a 4 stroke where the fuel mix is always on top of the piston.

'92BigBronco · 10-25-2003, 14:57

Hey, watch it buddy. LOL I am happily engaged to a beautiful girl BUT that doesn't mean I should stop doing what I'm interested in!!