Hey guys so I've got the chance to get 2 valve 351c 4 barrel heads and intake I want to put them on my bone stock 400 it's got a 2 barrel carb intake and heads. What kinda problems will I run into ?

 

@ mechanicman101,

You should probably start your own thread when asking a question.

edit: indeed he just started his own thread, think I just responded to the wrong thread..nope wait, a mod stepped in and fixed it..lol..

 

New thread, done.

 

Looks to me like this IS his thread

 

You will need to find a 400 intake that covers those big ports first. Ditto for the exhaust's headers will need to fit both a 400's taller profile in the vehicle and cover the ports. FPA is the only game in town here I think. Pistons will need to have valve reliefs to match the larger valves too.. Otherwise the valvetrain is the same.

 

The cleveland 2v heads are the best stock source. Mounting is no different from 351m/400. I think the compression is about the same too but the ports are much better.

 

I extracted the posts from a hijacked thread and created a brand-new one (this one).

He asked the same question in a different thread but I left it alone.
https://www.ford-trucks.com/forums/1...l#post18324694

 

You will have NO problems bolting on 2V 351C heads. Before 1975 the 2V C heads were the same head (baring part numbers) as the 400 head. After 1975 the 351M/400 head changed to accomidate the smog pump bumps in the exhaust ports. All your 400 parts will bolt on without a problem.

 

There were companies that made spacers to go between the heads and intake allowing one to install 351C 4v heads and intake on 400 blocks.

 

yes the 4v is a different animal and too much for most engines.

 

Currently Price Motorsport is the only one making spacers. I'm using a set on my 400. Price Motorsport

 

 

Bull-loney! The 4V heads worked on the 351 and will work even better on a 400. You didn't say whether the heads were open or closed chamber. That makes a big difference. For an open chamber head you need the Tim Meyer special pistons to creatre some squish in the chamber and get the compression up;. That's actually two different things. Getting the compression up can be accomplished with pistons with a larger compression distance. However to get some squish so you can use the higher compression, you need a piston with a lump that comes to the top of the chamber (within 0.040" or so) and gets the mixture moving. The TMI pistons do that. My 400 with stock replacement pistons pings and I've had to retard the spark to silence it. Getting some squish in the chamber is your best bet.

The 4V ports are pretty big and you need spacers with the right size holes to use the 351C intake. I understand they are available. There are some low production manifolds floating around but if you just plan to use the spacers you'll be ahead.

R.

 

Something that is way overlooked is how to properly CAM a engine with 4V Cleveland heads. I would suggest googling George Pence and reading what he has to say. Personally I would not invest in a set of 4V heads for a 351M/400, I would jump strait to TFS195 Power Ports. They are reasonably priced, come assembled, and would be cheaper than trying to adapt 4V heads to a 400. They flow better than the 4V heads, yet use 2V ports. They weigh like 30lbs a piece and standard 351M/400 manifolds and headers bolt right up. But that's my two cents. The 2V Cleveland head is a different story and for mild street use will work fine. They will need much more cam to get to the power levels of the TFS195's with even the most moderate of cams, but the 2V heads should be cheaper than either the 4V heads or the TFS195's.

 

With the stock 4v heads you will wind up with a high rpm torque band in a heavy vehicle. Not a good match. Not fun to drive unless you want performance over driveability. As above there are newer better options.