Hello,
I have some 2v cleveland heads that came off of a 351M/400 with a casting of D5and I am wondering if they are worth building or should I look for the earlier 2v heads? I plan on some minor port work, gasket matching an such, plus larger 1.71 ex. valves and standard intakes. I have a set of Aussie heads, but I have decided not to use them because I would have 10.5:1 or higher compression with my flat top pistons, which is more than I would like for this engine.
I have heard that the later heads have nasty smog bumps, would having them ported make them just as good as earlier heads? Thanks.
Cory

 

the later 351m/400 heads have the smog bump in the exhaust port, and I think the port is a little smaller but you could probably port them out enough to flow as good as the earlier heads, but the only major advantage of running the later heads is the induction hardened exh seats, and by putting in the larger valves you will cut that out so don't forget to put in hardened seats or sell your aussie heads, and you can probably get enough to get a good set of early C heads, and probably the new valves as well.

 

Look into your exhuast ports. If they look very restrictive don't spend the money on them. Get some earlier heads. The later M heads have a raised floor in the exhaust that may contain a water passage. Then again it might just have been an attempt to increase flow velocity to compensate for emmisions.

 

I am not sure of my casting numbers but the heads had the bump (not drilled out for the EGR though) and I had no problems cutting a LOT of metal out of them. I also did the larger valves.
If you are going down this larger valve road, you want bigger intake and exaust.
Read this: http://realbig.com/detomaso/1998-02/161.html
and this: http://www.jason.fletcher.net/tech/f.../cleveland.htm

According to Danlee of this board, and I agree, the ideal big valves sizes are 2.15 and 1.65 to minimize shrouding, which means having them cut down from what you can buy commonly. GL

 

If you look on BubbaF250s website there is a section that shows what the best heads are and which year to look for. Off the top of my head I think 77 is a good year because it had a 74cc chamber.

 

77 also used the castings with the restrictive exhaust port. I would agree with just finding the early Cleveland 2V castings and have the hardened seats installed, if you're going to run bigger exhaust valves anyway. I think I might know you from another board, Cory......

 

I have a set of CHI-3V aluminum heads. They flow 319 CFM at 0.600 lift. The Intake valves are 2.15 and Exhaust valves are 1.65. CHI says that larger valves are shrouded by the cylinder walls.

I would concentrate on the porting and the Intake valve, leave the exhaust valve as is.

 

This is from Dave Williams @ http://www.angelfire.com/ar/dw42/fordhead.htm :
(which is an excellent source and a long page on tons of heads, use your "find on this page" function and search "351C" and "351M" for the gems. BTW, danlee, he lists the weights for the heads I think you wanted a while back.)

==Oddball 2V Cleveland Exhaust Ports--------------------------------
351C-2v heads are popular for some racing classes. The 2V, 351M, and
400 heads are all pretty much the same, *but* some 351M heads have a
bizarre "potbelly" exhaust port, with a the top of the port lowered
to about the valve guide level. You can barely get a finger through
the port, it's that tiny. And for some reason it's part of the water
jacket, so you'll hit water if you try to grind it out.

 

Yes, my CHI-3V heads weigh 53 lbs less per pair than 351C-2V heads. These are a little expensive, but there are none equal.
The large port 4V cleveland heads might outflow them at very high lifts, but I don't want a cam with that much lift due to the overlap that wil come with it.


Note about 351C-2V heads:

"pocket ported" intake 203 CFM at 0.400, exhaust 145
| will not flow much more unless a bigger intake valve
| is installed. Exhaust valve size will not improve
| the flow any.

 

Indeed, the major disadvantage of later ('75-up) heads is the lowered water jacket around the exhaust valve guide, however, it might not be as much of a disadvantage as you would think. I've seen flow bench testing on stock, unmodified heads that showed some, but surprisingly little difference between earlier heads without the "potbelly" and later heads with it. And even with the lowered water jacket, the later heads can still be ported to flow significantly better than stock.

This feature was introduced in MY1975 heads, and continued until the end of production in 1982. I believe it was intended to improve cooling for the heads to mitigate low-octane pinging, which was a major concern for the 400 when unleaded fuel was mandated for MY1975.

Just in casual observation, I noticed very little difference between the ports on various '75-up M-block (351M/400) heads. Unfortunately, I did not consider port differences when measuring the heads listed on my web site.

The earlier heads (pre-'75) obviously have a better exhaust port design. If you intend to do some serious porting, that could be an important consideration.

 

is there a left and right side for the 2v cleveland heads or do they fit any side?

 

the early heads will fit either side, the later heads with the smog fittings are side specific, but if you are plugging them off then you can put them on either side as long as you can still bolt your accesserious up.

 

Yea Im sure its from a couple boards, the N54 cleveland forum and classicbroncos.com.

My cleveland is in my 1966 bronco, and it is built for all low end power and torque. I want the larger exhaust valves to aid in the torque, the intake valves I figure are large enough, maybe some 2.09" 460 valves would be good though. The cam isnt a high lift or duration, it is .469"In/.505"Ex and .255/.265 adv dur. so I do not need high flowing heads. Even though the engine still peaks at 5500 RPM. The torque curve peaks just over 2500 and is flatter than a board across the rpm range. I just want a simple port job and I need to rebuild the heads I have anyway, the valve stem seals and probably guides are worn out. Thanks.

 

I kinda thought that was you. I'm heading to the Mid-America Shelby/Performance Ford meet here after I get off work. They have drag races and a swap meet today, then the car show and swap tomorrow. I'm going to see if I can find someone giving away an X-cellerator intake for 2V heads. Yeah, right. I've seen the link where some different intakes were tested, and the X-cellerator makes more torque across the RPM range than the Performer does, so I'm going to see if I can turn one up a little cheaper somewhere. This meet will probably have mostly FE and Windsor stuff, but it doesn't hurt to look. Besides, there's nothing like a lot full of Shelbys, Panteras, Cobras, Tigers, and all other forms of old Ford muscle. It's my yearly addiction.

 

Sounds like a good event. I havent been to any good swap meets here on the west coast. Someday I hope to make one of the many Pamona swaps, they are supposed to be really good, and the happen like every other month or so.