I did some searching but never really found the true meaning of a "bolt in" cam. Would it be a cam that can be used as a direct replacement of the Mfr stock cam without changing/altering: heads/valve size/springs/pushrods/gasket thickness/etc ? Not that an application could certainly benefit from changing any of the above for optimum performance but designed to be an improvement if just used as a direct stock replacement of standard cam ? Also having to consider the cam mfr recommendation for intake/exhaust. Also EFI tuning would be a given. Just wondering ??

 

You are correct.

 

Add using the std. chain drives for the cams to your definition.

 

I don't think you can assume that much. I think "bolt in" means the cam itself fits in the engine case in but the lifters, pushrods, gaskets, etc. need to be fitted to the new cam geometry because the lift is different than stock. It is an advertising-type term, not necessarily 100% accurate to run with without knowing the details, imho.

 

I would describe a bolt-in cam as one that can be fitted without any modifications. In other words it will pep up a stock or near stock motor. Other cams can require modifications to the crankcase, just to get them in, or need higher compression to work well, or head modifications, etc.

There is a whole range of cams, from mild performance through to outright racing, with increasing modifications needed to make them work. Bolt-in cams are on the bottom rung of that tuning ladder.

 

Bolt in cam: a cam that can be used as a direct replacement of the Mfr stock cam without changing/altering: heads/valve size/springs/pushrods/gasket thickness/etc. uses stock base circle.

would likely benefit from additional compression and head work, but not required for it to function

 

I just had a (bolt end cam) installed se255 adj. pushrods. Now they cant tell me why the tq is to the right( not the low to mid range tq 255 is supposed to do). Also tell me the clicking I hear in rear cy. is a lazy lifter and the knock I hear at 55mph in 5th gear (6speed trans) when I roll on gas is because to low on rpms. The knock I hear when shifting up the gears first gear up is not happening. So bolt in cam #@$*$#@ no no no If you are luckey yes if not you could be in for trouble.

 

I gotta disagree. Should be just as the OP described.

Lift being "different that stock" is what makes it a performance upgrade.
You don't need the pushrods until you alter some other geometry, such as head gasket thickness, shaving the heads for compression, etc.

Bolt in is straight up what the OP thought in the first place.

They all do that.

 

Not sure what the book says, but I sure would not have called the 255 a "bolt in" cam. It needs the right compression to behave correctly.

 

Who is "they"?
As for the clicking, how many turns did you adjust the pushrods?