between roller cams whats the difference between retrofit and oem?

 

Retrofit is usually for pre 87 blocks that didnt come from the factory with roller provisions. Oem is for a standard factory roller block. You seem to have the oem type.

 

but the question is, why the difference, what are the physical differences?

 

OEM block is designed for roller lifters, has the spider web to hold them, and a retainer behind the timing chain (which is different) for the cam. Retrofit has the lifters linked in pairs, and requires a button on the timing chain gear to keep the cam from walking out of the block.....and costs much much more.

 

oh thats lame about the button, i guess the stock plate that slides over the cam wont fit over the retrofit?

 

There's no place on an older block to bolt it.

 

To bolt it in you need to drill into an oil galley, a few people here have done it and some with not so good end results. Another thing is trying to get a bolt to seat good in suck thin material without breaking it, if the bolt goes in too far youll block the galley which isnt good either.

If the bolt comes out say good bye to oil presssure and if the lifter turns in the bore you just lost yourself a cam and lifter(s)

 

ok lets imagine, i have an oem roller block (cuz i do) and i wanted to put a retrofit cam into it (dont ask why)

would i be able to use the cam retainer plate? and not use button. also do retrofit cams use standard cam sprocket bolt pattern?

 

lol, i just have to ask...

Why the heck would you use a retro cam when you could use a regular roller cam?

 

There won't be a groove in the front of the cam for the plate. The retro cam would use the standard bolt pattern.

Edit-the factory roller cam has a tighter bolt pattern b/c of the groove in it for the retainer plate.

 

thanks lo tec you answered my specific question, mainly thats what i wanted to know. you da man!

 

A picture is worth 1000 words.



Flat tappet, factory roller, retro roller.