pr1689

I had purchased a set of Comp. Cams Pro Magnum roller rockers, 1.5 ratio. I have been rebuilding my engine and had a local mechanic friend come over to inspect some of the work I'd done. He said everything looked great with one exception. He felt that I needed to use the self-aligning roller rockers since the top of the valve set so much higher than the top of the spring. The springs can handle a lift up to 600.

The engine is a ZZ4 build. It's an 87 350, 60 over, zz4 cam, 113 casting aluminum heads, tpis big-mouth intake, large tube runners, flat top hypereutectic pistons. EDIT: Also, the heads have guideplates installed.

Any advice on this would be greatly appreciated. If I need to get the self-aligning rockers, I need to get them quickly as I was going to install the engine this weekend.

Thanks for any and all help,

Pat

pr1689

Bump. Anyone have any ideas? I thought that with guideplates, you didn't need self-aligning roller rockers. But the guy that looked at it said he would be worried that they would slip off the side and throw a pushrod. There is some movement side to side, but it just seemed a little extreme to me.

Apeiron

I have no idea what he's talking about, and possibly he doesn't either.. If you have guide plates, you want non-self-aligning rockers.

pr1689

Ok, that is good news. The guide plates are installed under the screw-in studs and it all looks good to me.

Should there be some side to side movement? That was the concern he posed.

Thanks,

Pat

Apeiron

Yes, there will be a very small amount of sideplay regardless of what method is used to locate the rockers.

pr1689

Ok, thank you very much for all the info and advice!

Thanks again,

Pat

Guest

With guideplates, no you dont need nor want self aligning rockers. I gotta ask though... are those aftermarket guideplates? The GM ones that came on some corvette AL heads arent compatible with hardened pushrods. FYI.

pr1689

Well they are the GM guideplates, so it looks like all I need to do is get a set of aftermarket guide plates and all will be fine. I'm glad you mentioned about the guideplates, that was something that would have caused me a bunch of trouble!!

Thanks everyone for all the help! I really appreciate it!

Pat

Apeiron

Just use the guideplates you've got.

pr1689

Well, I've got the hardened push rods, and after looking up the info for the head, it states that it uses the rail-type rockers with the gm plates, or you can use non-rail type rockers and change the guide plates.

Do you really think I can use the existing guide plates??

sofakingdom

iTrader: (1)

It's the other way around.... you either use the guide plates with non-rail rockers, or you ditch the guide plates and get the self-aligning rockers (with rails).

pr1689

I'm didn't describe it very well, but that is what I was trying to say. But it said to replace the existing guide plates if I was going to use non-rail type rockers.

My whole concern here is that I don't want to get it all assembled and then have to redo all the work I've done so far. I'm assuming that if it's calling to replace the existing guide plates if using hardened push rods, that maybe it would grind on the GM guide plates and create some filings which I don't want floating around in the engine!

Does that make any sense??

Thanks,

Pat

Guest

Makes sense to me. The factory plates will get torn apart with hardened pushrods. Either run standard pushrods, or get some aftermarket hardened guideplates.

old Phart

iTrader: (1)

madmax----I just read your post and now I'm worried about my engine work recently done. I have an original 5.7 350 engine in my 89 IROC with 92K miles on it. Two months ago, a local Corvette and Camaro auto shop installed Chrome Moly pushrods in my stock motor, along with Comp Cams Magnum 1.5 Roller Rockers (part # COM-1417-16) and new cam, XR 264 (part # 08-501-8). I put about 2,000 miles on my Camaro already. Am I going to have problems with this set up?

Guest

Assuming you have the factory iron heads and self aligning rockers, should be fine.

pr1689

Ok, I have one last question, the current guide plates are flat and are obviously what I will follow with. Is there a certain size I need to get with my comp cams pushrods? I would assume that there are some larger width cutouts in the guideplates. I'm sure this is a pretty noob question, but I really don't know.

Thanks,

Pat

pr1689

bump...

Guest

That all depends on what pushrods you got. 5/16? 3/8?

Stepped or flat doesnt much matter IMO but I went with flat ones for mine. Either Comp cams 4808-8 or 4810-8.

pr1689

Ok, great! Thanks a bunch!! I appreciate it and that does make sense!