I super confused on this topic. I hear that in 1987 GM switched some things on their small blocks.But I had the last year for a LG4 but the first they were rollered, right? One thing is valve cover bolt positing and switch to a roller type valve train. I will soon be ordering a intake and a cam from summit and will find out ether way but I want to see if anyone would know for sure before I rip the top end apart because I need to do a top end rebuild on it. (I know I have the new style rocker covers.) If it indeed is a roller, the parts cost parts just went up. I want to keep this engine. I don't have the space/ time or money to be doing an engine swap, although I'd love to. Simplified. What type of roller cam and would you guys recommend, and with a slightly bigger cam would I have to worry about putting in brand new stock OEM valve/valve springs/lifters/push rods along with a less then mild cam, or would I have to put in like aftermarket performance stuff to handle the bigger cam? just to get a little above stock. Like 210-225 lift at .50. Thanks for the help! If there is a roller kit available LMK! And/ or is there a way to convert a roller to a mechanical? Thanks guys!

 

Ok so I did some talking and looking and I see that I do indeed have a roller shown by the new style valve covers. So question is now- What cam and with that mild cam would I be alright replacing the upper parts with stock OEM rated parts from my local Auto parts store with out risking premature failure?

 

There are some mis-statements here that need to be cleared up.

First, it's not "roller vs. mechanical". It's roller vs. flat tappet. The lifters are still hydraulic, not solid (mechanical), they just have a roller following the cam now. This started in 1987 for passenger car and "performance" applications. Trucks didn't get roller lifters until 1996.

Also in 1987, the heads were changed for the center bolt valve covers. Good move, in my opinion. The head/intake mounting interface also changed, with the center two mount bolts on each side going to 72 degrees on the iron heads (Vette aluminum heads retained the 90 degree bolt angle for all of the bolts). All SBC's got this (except the Vettes noted above), passenger car or truck.

Although the cost for the cam went up, you can reuse roller lifters that aren't damaged (primarily the roller). You don't have to get new cam and lifters together like you do for flat tappets. I'm using stock factory lifters in my engine. It is a much better set-up than flat tappets, so it is worth the little bit more the cam will cost. You don't have to get anything else special (timing set replacement is usually a good idea regardless). If you go for the cheaper flat tappet cam and lifters, you'll also have to change out the pushrods (flat tappet pushrods are longer than roller lifter pushrods).

A cam in the 260 advertised duration range with less than .480" lift should do fine without any further modifications. Valve spring replacement should be considered mandatory whenever you go with an aftermarket cam.

 

Thanks so much 57kid as always, so informative. So, I want to keep it simple, bc when it gets complicated I get confused lol. I will want to keep the roller system. I'll look at a roller cam in those Numbers and also I was going to change all the upper parts out, when you say valve spring replacement, do you mean with new, stock oem's or aftermarket ones? Thanks for the write up, I'm printing it out and keeping it for my records!
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something like this perhaps?
http://store.summitracing.com/partde...00%2D8&FROM=MG

 

Aftermarket valve springs. That cam would be more than stock, but still fairly mild. The .488" exhaust lift would require verifying each exhaust valve travel before installing (verifying the intakes wouldn't be a bad idea, either). You should have at least .060" more valve travel than lift.

 

ok, i see now. Maybe I'll try to find one with a little less lift. What type of valve springs/ cam would you recommend?

 

If you want some more terminology help, read the article in my sig.

 

Just curious, why could you not use a normal flat tappet cam with roller lifters, in a roller block?

 

good question. So what kinda of valve springs should I be looking at? Or should I just tell the shop that I'm taking them to to get rebuilt to put in beefier springs?

 

double post see below.

 

Roller lifters will not work on a flat tappet cam.

A flat tappet cam's lobes have a profile that is raised in the middle where the lifter and cam touch. On a roller cam the lobe profile is flat. Further the ramps on the lobes are much steeper on the roller cam.

your flat tappet has a much smoother ramp rate than the roller, so using a mild cam thats a FT with rollers will only hinder any performance gain you hope to accomplish with a bigger cam.

I think the front-most journal on the cam is shorter with rollers, which is why the flat tappet blocks retrofitted with a roller cam require the use of a cam button and retainer to prevent cam walk.