Is there a 73 351 cobrajet? If so, how much are they worth in fair condition? I ran across an add yesterday and asked the seller to send info on the specs. He is asking $1200 with a c6 and 2500rpm stall converter plus an extra 351c as spare parts. Can anyone give me as much info on this engine as possible? If this is for real, I'd like to be well informed as to what to look for to make sure I am buying the real deal and not a mock. Thanks guys...........

 

It is a a 351C-4V Model CJ, It has large ports and a domed combustion chamber (75.4cc 9.0:1 CR). They are not worth $1200.00 with a fresh rebuild.

The C6 is the small block C6, and would bring some money.

If it runs good and you need something to put into a vehicle, it would be worth $600.00.

The small block 400 is the one to get.

 

danlee,

Thanks for the info. I just got an email from the person and he mentioned that he had it posted last spring and that the person that was gona buy it had a family emergency so he did not get it. He also mentioned that the guy was gona buy it for more than the listing price which does not make sense. If I were the buyer I'd generaly offer him less money and I think that would be just about anyone for that matter. He also mentioned he had flat top pistons but the rest of the rebuild was regular but professionally done adn the compression was 10:1 I believe. This might bring the price up right? Would this be suitable for a daily driver? I would like a few goodies but keep it at low octane. Don't know much about compression except the higher you go the higher the octane right? What is the cutoff point before you jump to the next octane grade?

 

At 9:1 depending on the cam you may run out of pump gas operation.

 

At 10:1 compression, you'll want the highest octane you can get.

2¢

 

This is a link to some good backround info on Clevelands. I think it should answer most of your questions.
http://reviews.ebay.com/Ford-351-Cle...00000001410755

 

Brian,

Thanks, great info.

As for the compression, I guess that engine is not for me then!

How can you tell how good a head job is done? There was another guy that was selling a 351c engine block and the heads. The block had only been vated and the heads he said had a 3 angle vlave job. There were some more parts like 7 hipo pistons (flat top maybe) with light weight rods and some more parts all for $250. I think it incleded a crank that had to be turned. Don't know the year on that one though. I thought about getting that one just for spare parts but I've been working nights for the last ten days and maybe he sold them already.

 

The '73 351C had 75.4cc heads 0.019" deck clearance and flattop pistons. It was 9.0:1 from the factory. To get 10:1 he would have to put dome pistons in it or mill the heads or deck the block. At 9.0:1 it would run on pump gas, maybe regular with a stock cam. At 10:1 it would need a fairly large cam to run on anything less than 93. These are open chamber heads, so there is no quench.


What heads did the fellow that was selling for $250 have? A good set of 4V closed chamber heads are worth that, if that is what you want. I sold a set without valves or springs for $500.00, but they were in excellent condition and had hardened seats and recently installed valve guides.

 

yea, they dogged the cj in '73 and had it down to like 220hp. what a joke...but a few tricks and it could be a terror with earlier heads etc. someone rebuilding a torino to spec would pay 1200 for it I'm thinking. I have a '72 torino with a 351cj and am fixing it up to sell.

 

danlee,

If I remember correctly, I beleie he interchanged heads between the 2v and the 4v. Would that raise compression to 10:1? About the $250 parts, they are 2v and so is the engine block that comes with it. Can those heads be used in a 351m? If so what difference will it make on performance? I have read of all kinds of combos with heads and internals that at this point I can't remember what does what and where. Perhaps it would be nice to build a chart with different combos to helps us out right?

 

Tom Monroe's book 'How To Build A Ford Engine' has an interchange table for all the engine combinations.

Those early 2V Cleveland heads are good for a swap to a 351M or 400 motor. They don't have the exhaust bumps and they have slightly smaller combustion chambers.

 

What kid of performance gain is there? Is it worth the $250?

 

If your vehicle is runnning good, I don't think that it is worth the cost and risk involved in swapping heads.

On the other hand, if you need some head work and you can get these for $250 and maybe save the head work, you will get some performance gain for little money. That is if the $250.00 heads are in good condition.

 

I really don't know what kind of performance I have on the engine. I bought this truck from a fellow here on this site two years ago and have not done much to it for one reason or another. Anyway, I just thought tha maybe the heads might be at a good price and could serve as spares or like I mentioned above to boost performance of the 351m. The last time I posted about the truck I bought it had issues with the carb (edelbrock1406 , bad exprience from edelbrock which really disapointed me with their procuct support but that is another LONG story) and just got another one not too long ago but have not tried to tune it since then. The specs on the internals are unknow since the seller did not know what went in it since his friend did the work. He believes most is stock except for cam being a mild cam. Engine 351M bored .30 over rebuilt in 1998.
C-6 trans also rebuilt in 1998.
Both have small leaks. Oil pans.
No coolant leaks
MSD Pro Billet distributor.
MSD 6A ignition box.
Holley commander 950 EFI w/Wide band O2 upgrade. Use laptop to tune engine.
New optima red top battery.
New painless wire harness
March performance aluminum pulley set.
Edelbrock 2171 aluminum intakebox, MSD.

Everything but the fuel injection system is on the engine. Decided to go with carb due to technical dificulties trying to tune the fuel injection. Pics are available on my gallery....

 

A set of Aussie heads would do more for performance, than the CJ heads. Then again you will not get a good set of Aussie heads for $250.00.

I think that you should save the money until you have enough to do a 400 conversion with Aussie heads.