Hey,

I have a 56 F100 with a 351C 4bbl heads, and an FMX.

I have heard that the Clevland 4bbl heads are crappy for use in a truck, and that it is a top end powermaker.

I was looking at some parts the other day and I found an edlebrock intake and a crane cam, both were for lower end power, I was wondering if putting in parts that create power at lowere rpm will help this motor preform better for the street or will it just be a waste of money with the 4bbl heads?

Also, I was wondering if it would be possible to take a 400 block and such and just replace the pistons and heads with mine, then I could have a nice little bump in displacement, but then i would still have the crappy heads...although I would have a bump in displacement to mkake up for it?

Tell me what y'all think please, remember I am poor...

 

the added cubes of the 400 will wake up the 4V heads some, but there are no "off the shelf" intakes that fit the 400 and have the 4V porting. you have to use intake spacers and a 351C intake, maybe a distributor spacer to lift the dizzy up to clear the intake too. you can also use C pistons in a 400 but the wrist pin is a different diameter. the 400 rods need to be bushed to the smaller C pin size. why would you want to use your C pistons? if you're really poor, think about stamp collecting? there are at least a couple of 4V 351C's in street trucks that are rockin, but i wouldn't really recommend it for a 4wd work truck. a bit of a stall converter will help get the ball rolling too. is it 2wd/4wd? and what rear gears?

 

its 2wd, Im not sure of the rear end is, the guy said everything came out of a Mustang, but wouldn't they have put a c4 or c6 behind the 4V engine? Im gonna buy 3.XX posi for it hopefully

Its just supposed to be a cool 50's kustom, so I don't care about racing it, and when I drove it before the rain (its stuck in the mud right now and the tractors broke...) it seemed to be pretty powerful, so I dunno.

What about the intake/cam that I was thinking about? would the lower rpm parts work with the higher rpm heads? It has long tube headers and an Autolite carb by the way, but im thinking about getting either a demon or whatever will work best

 

oh yeah, I made $32,000 last year so im not THAT poor, just really...really cheap

Haha

 

You can pickup a set of stock 2V heads for that motor that will work great. Have them ported and matched to the intake you want to use. I just did this in my truck.

I am told that 4V heads are great for racing, but not for trucks and street drivers.

All you need to make your 351C a 400 is flattop pistons. The blocks are the same. I did this to my 351M in my 78 F150. Changed the crank and the pistons, and POOF, I have a 400 with a longer stroke and higher CR.

A 50's custom truck would be really cool, if done right....

 

Say what a 351c, and a 400 are not the same block at all, and changing pistons doesn't change the cubic inch of any engine you have to either bore it or change the crank to change the CI. a 351c is a 9.2" deck hieght the 400 is 10.3" the cleve uses 2.5" mains, and the 400 3" mains the cleveland uses a small block bell housing most (there are a very rare few 400s that had a small block bellhousing) other than the the 351m/400 use the big block bell housing.
Now onto the 4v heads they really aren't the way to go for a street driven truck either go with 2v heads, and flat top pistons, and have them ported or go spend the money for a set of alum aftermarket heads but definatly not cheap although looks cool

 

I mistyped....

The 351M and the 400 are the same block, and no, you don't have to bore it, just change the stroke, IE add flattop pistons and a new crank.

The 351C motor is similar to the 351M but not exactly the same, even thought they are the same family of engine, the 335 series. And from your description above, it says you have a 56 F100 with 351C heads, but it doesn't say exactly what engine they are on. I looked at putting the 4V heads on the 351M, but was told they are for higher RPMS and have very littel low-end torque so I decided against them.

And yes, you repeated what I said about the 2V heads. This is exactly what I have done. I ported/polished the stock 2V heads, added flattops pistons (with a 400 crank to make the motor 400 CI) and a good cam. Now I have a 400 instead of a 351M.

So which 351 do you really have??

 

I was hoping you had mistyped but you never know some people really don't understand that there is a difference, and I basically was backing you up on the 4v vs 2v heads because it's good advice, I assume he really has a 351c since it's what he header states, and he says he has a 351c with 4v heads. Now if he has 4v closed chamber heads he can sell them for enough to buy a set of 2v heads, by good valves springs locks, and retainers, and probably have most of the machine shop bill paid thus staying within the cheapo claim

 

Yes, true. The 4V heads are quite valuable with the closed chambers.

When I think of a 351 in a truck, I assume it is a Modified, especially in 56 when neither of these motors existed. I guess I shouldn't assume....

But yea, the M motor is made into a 400 easily. When I had mine built, some one told me that I was wasting my time with the 2V heads and should have gone with the 4V head because the ports on the Performer intake are so much larger than the ports on the 2V heads. Well.....when I got the intake back from the powder coating shop, guess what.....the intake ports had to the BORED to match the 2V heads. Yea, he knew what he was talking about.

And he can certainly get a set of 2V head fairly cheap, even if he wants to go Aussie.

 

as far as I know its a Cleveland, the guy said all the running gear was from a 1970 Mustang. I checked the side of the heads where some website said the the 4V heads have a 4 on them and they had that, and I opend the valve covers and it had that weird (canted?) valve arrangement so im pretty sure its a 4v.

I thought the FMX was a crappy trans that was put behind the weaker engines though and its seems odd to have that behind the 351C 4V as I have always heard that the cleveland was a preformer?

I really don't want flat tops, the CR is already way too high (10 to 1?)

what about the lower rpm power parts? The edlebrock intake and the cam that I mentioned earlier? would my engine benifit from these parts at all or would they just conflict with the high rpm nature of the heads?

Keep in mind that the truck will only be used for cruising and parts running, so it dosen't have to be a monster

 

how do I tell if they are open or closed chamber?

 

still too many mysteries, how do you know that the CR is 10:1? low end cams generally don't want that high of a CR. do you have any specs on the proposed cam or the grind # and manufacturer? the FMX trans is a medium duty unit with no overdrive to burn up, old school technology that can be beefed up by any competent builder. not a lot of fancy aftermarket parts but all performance build principles apply. shift kit, increase line pressure a little, lose the waves, thinner pressure plates, add clutches, lighten the accumulator springs and a little stall(2000-2400) converter... if you aren't after a monster you would be better off with the 2V heads. Comp Cams 268H is awesome in a 2V Cleveland, and the performer intake is pretty much an aluminum stock intake that lets you use a 4bbl carb on 2V heads(or 4V). some guys say that a stock iron 4V intake is better than the performer except for the weight. the edelbrock is OK for a driver, it has smaller ports than stock for better response at low end. do you have access to a boroscope? it will go in through a spark plug hole and you can see inside the chamber to find out which heads you have, and the pistons too. have you heard of the Parker Funnelweb intake and the port stuffers?

 

if it is from a 70 mustang 4v engine then it should be closed chamber heads, the main problem with dropping a low end cam, and edelbrock performer intake on the 4v heads is that you still have the huge ports, and valves of the 4v heads (they use the same valves as the 429cj heads, and bigger valves than a set of stock 460 heads) so your low end port velocity stinks, although they can be made to have SOME low end performance what will happen is you will sacrifice you performance all around because just as the heads are starting to work the intake, and cam will run out of there power band, you best performance is when all of you components match, and the 4v heads on a 351 CI engine really don't even start to perform until around 3500+rpm. Now on the other had a 2v cleve engine can be made to give tremendous power on the low end without totally lossing the top end power with the right parts my race engine last year was running 2v heads (although they were aussies) and I was shifting at 7200 rpm. A parker funnelweb is an awesome intake but it is a highrise single plane intake (very similar to an edelbrock victor only better) but on 2v heads it will out perform a performer intake, but on 4v heads will make the engine even doggier on the bottom end. If it's just a ego thing and want to be able to say you have a 70 mustang 351c 4v engine in there then by all means keep the heads put a parker on it with about a 750cfm dp holley, get a 3000-3200 stall convertor, and a dual pattern cam with a set of lower gears and have fun but if you really want some low end power sell the 4v heads and build for the lower end.

 

If this truck is going to just be used for work and running around, you should pull that engine and dave it for a street-rod project later. But I would like to see you make a rod out of that old truck....that would be really cool.

 

So Pick-N-Pull is having their monthly "half off sale" pretty soon and since heads are only like $150 regular, they would be like 75 bucks, not bad...

Are the 351M heads identical to the 351C 2V heads? How about the 400M in case I can't find a 351 (VERY doubtful)
Will my stock intake work with the M 2V heads? How about my pistons?
pushrods?
camshaft?
headers?
Should I pull the intake along with the 2v heads and use that? Also I have heard that the M dizzy is better (electronic?) should I get that too and will it work?
Is there anything else I will need?

The cam was a crane, my computer is crapping out right now so I cannot get onto the website, I do remember that it was one level up from the lowest and that it started with M, As for the CR i found that on some website about Clevelands.

My plans for that truck are to build a simple 50's style Kustom. It is already flat black and has crappy white American Racing wheels but my buddy who has a 66 F-100 Kustom said I could have his steelies.
I plan to lower it was much as possible while retaining the stock suspension (no mustang II, no Volari), Chop the top (although I highly doubt I am skilled enough), remove the stock gas tank and replace it with a Mustang style, stuff like that.

I have already removed the door handles and am going to fill the holes soon, im hoping to get an autolok shaved door kit but I would like to keep it 50's and without electronics, if anyone knows how to do it old school let me know. I removed the grille as it was pretty dinged up and am trying to make a custom spiderweb grille. I would really like to get fender skirts for the rear but don't know if I have the skill to build them.

Sorry that that was so long, thank you all for your help.