I had a 383 built at a local machine shop, I gave them a 98 l31 roller block and ordered the rest of the parts thru them.

I talked alot with the owner about wich cam to use...ended up going with comp cams #12-404-4

The motor ran fine for the 30 min break in and about 60 miles of driving...then started surging under load and throwing random misfire codes.

I called comp cams and the cam # given to me by the machine shop is for a flat tappet cam...recomended for 350 tpi motors

I called the machinist, and he says there would be no way to install a flat tappet cam with the retaining plate, and gear...he is claiming he gave me the wrong cam card..

Is he bullshitting me? is it possible to mistakenly put a flat tappet cam in a motor when you thnk you have a roller cam?

sorry for the long post

it for sure does have roller lifters btw

 

Flat tappet cams don't have the machined groove to facilitate the cam thrust plate. Flat tappet cams can go into roller blocks just fine, so long as you have the correct flat tappets.

I am slightly confused. Your machinist aquired said camshaft, and upon inspection of camshaft, realized it was a flat tappet? But proceeded to use the roller tappets anyway? If so, pull the cam and lifters and inspect everything. They're 2 differently designed components, and not designed to be used with eachother. Roller lifters expect the cam lobe to be perfectly square. Flat tappet lobes are ground so that the lifter spins in the bore. They don't like eachother - the flat tappets angle-ground lobe surface puts excess load on one side of the roller lifters bearing. Can cause excessive wear, and eventually failure.

Bottom line, if the case is as I outlined, then get a new machinist.

 

Sorry if the post wasn't clear.



I had the machine shop assemble the bottom end and put in the cam, I put on the heads, intake, lifters etc..



They told me it had a roller cam (I had specified this as I gave them an oem roller block) and sold me a set of roller lifters when I picked up the completed motor.



I also got a piece of paper with the "supposed" cam specs and comp cams part # on it....I looked at the specs but never searched the part # online.


When the motor started running like **** I evntually ended up calling comp and they told me the part number and specs I was given were for a flat tappet cam.



But since the cam thrust plate is installed I'm going to assume it's a roller

 

megan fox saying Camshaft = BONER

 

I'd still pull the cam.