NSR

I'm rebuilding the engine on my winter vehicle. It is a '91 K5 Blazer with a TBI 350. I know the original engine had a roller cam but was told by previous owner that the engine had been replaced and I need to know if this engine has a roller cam or not so I can order new parts for it.

I have the cyclinder heads and intake manifold off, but still can't tell. I thought that with roller lifter's there was some extra metal in the lifter valley that holds the lifters, but I'm not sure and I don't see this on my engine. When it stops raining I'll try to get some numbers off the block, but I was wondering if anyone could tell me how to identify a roller cam/lifter engine from looks? Or if someone has a picture of a lifter valley from a roller engine that I can compare to? Thanks.

RB83L69

The only way to tell is to look.

The block numbers will be the same whether the prior owner replaced the cam or not. That will not help. For that natter, the same block casting was equipped with rollers in some applications, and wihtout them in others.

There is in fact a big piece of sheet metal all in the lifter gallery area of a factory roller cam motor, because the factory put their summer engineering intern's sophomore prject into production instead of doing what all the rest of us had been doing for all the decades before the factory "discovered" roller cams; namely, lifters were joined together in pairs pre cylinder by a link to keep them from turning.

There's not many parts where it makes a difference whether the lifters are roller or not. What are you working on? It may be a moot point.

NSR

Thanks for the response. I thought there should be a piece of metal in the valley but my engine doesn't have it, so I assume it's not a roller cam. Also the lofter's spin in there slots. I'm trying to figure out why there isn't any compression in the #5 cylinder. I decided while I'm at it I'd rebuild the top half of the engine and clean up everything I can without actually pulling the engine out.

The reason I'm trying to figure if it is a roller cam is because gasket sets are twice as expensive for those engines. Also it would be nice to know if the previous owner told me the truth about replacing the original engine with a Target Crate engine. My truck has 235,000 miles on it, but supposedly the engine only has 100,000. Do Target engine's even come with roller cam's?