What the heck is this

7173Mustangs.com

Help Support 7173Mustangs.com:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.
I thought so I though that (R0890) would tell me who the builder was ,That goes along with the different color heads I see now their has been work done to this motor in the past



 
If you check the date codes and the VIN# on block probably do not match your car. Common in past to just swap your core for already built engine.

Fellow here owns one of the prototype Boss 429 cars. He got it cheaper, well over $100,000 because it was not numbers matching. About 6 months after he bought the car he got a message from someone that had his original VIN# matching Boss 9 engine. I think he paid a sum for that so now numbers matching prototype. Prototypes have two build sheets and two different Marti reports. One with 428 CJ and one with Boss 429.

If you had an issue with a Boss 9 car the dealer could not work on it. They pulled the engine sent to Holman Moody and they just sent you what ever engine was ready. That is how his engine got mixed up. Nobody worried about numbers matching back then.

 
That's all good stuff , I got to try again and get a mirror in the left side and look for that original vin. I haven't done much about this engine lately ,just some sanding on the body (I had my own body shop in the 80's) ,as soon as it gets a little warmer yesterday my new spark plugs fouled out all of them took the valve cover off passage side so in a few days ill try running it again and ill adjust the valves ( I hope their hyd lifters) If all of this don't work (get the shaking out) im also going to plug off all vac lines,, ,,,then its time to take the engine out and start from scratch ,,Dave I Hope that not the case here with the engine motor mount and exhaust pipe I can't get a mirror in their ether

 
Last edited by a moderator:
Unless someone has had the heads machined for adjustable rocker arms or installed the Crane conversion the valves are not adjustable. They are hydraulic, unless someone slipped in a Boss engine.

The plugs likely fouled due to rich carburetor or oil. If they are all fouled I would start with carburetor.

 
I think the cylinder head casting numbers are under the intake ports, so you'll only be able to see them with aa magnet if you pop the intake off.

Can you post up a picture of the date code and cylinder head that you have the VC off of? It would be simple to see if you have adjustable valves.

Honestly I would put your efforts into figuring out what you actually have vs. trying to figure out what that tag means. That engine has been messed with, try and rule out the 'tune' related things that could cause your condition and check them off the list. If all those items (complete fuel system and ignition system) are up to snuff then start looking into the insides of the motor.

Just my $0.02...

-Matt

 
I did do some ignition parts im waiting for others to come ,,I do have to take the head off cause I found a exhaust bolt broke off in the head I haven't taken the exhaust manifold off maybe i'll get lucky and find it sticking out a little,,i thought about buying a new holley (if that's not the problem I could always sell the old one)



pic share

 
Nope, those are factory Cleveland bolt-down rockers and are not adjustable.

Date code is 9L19, wich decodes as 1969 - December - 19th day.

Can't see the number on the corners of the heads, so you either have closed chamber 4V heads, or standard open chamber 2V - unless it's actually 1979 and they are 351M/400 heads.

 
Back
Top