Im going to be installing RR's to my '88 C4 with stock heads soon and after reading more into the subject I think Ill go with Comp Cams magnums. Still have a few questions though: Is there a difference between the magnums and the ultras? How do I decide what ratio I need? I read that full roller is better-how do I tell if ones are full rollers? On ebay I found the comp cams for $138, are these the correct ones for my engine?-PN is 1416-16

 

those are roller tip, full rollers also have a roller in the center that the stud goes through, the picture on this link is a full roller http://www.compcams.com/information/.../ProMagnum.asp from what I understand full rollers wont be too much better than roller tips on a stock motor and are around double the price of roller tips

The part # you posted are for perimeter bolt valve covers so they won't fit on your '88, comp cams PN 1418-16 are roller tip with 1.6 ratio that fit center bolt valve covers and are self aligning like the stock rockers, my brother bought them for his '88 but hasn't installed them yet.

As for ratio I'd go with the 1.6 for the extra hp, I don't think 1.5s give much at all over stock. I'd also throw in a set of new valve springs that are slightly stiffer, LT4 springs would probably work well, and you might as well throw some new valve stem seals on while you are in there also.
Anyone feel free to correct me if I'm wrong

 

There are quite a few things to consider before doing a rocker arm swap.
1. Is this going to be the only mod or the beginning of much more? If this is only the beginning you might want to consider the 1.6 ratio rocker instead of the stock 1.5
2. If you decide to go with a 1.6 ratio rocker you will need to replace your stock springs too.
3. Are you thinking of a cam change in the future? If so you will want to consult the cam manufacture recommendations for their cam as to what type of rocker to use.
4. If you plan further mods you might want to think about going with 7/16" studs over the factory 3/8".
The rockers you show (1416-16) is a 1.6 ration rocker which would give you about 10 more horse power but would require changing springs. Also its a roller tipped rocker not a true roller rocker which would look like this http://www.jegs.com/i/Comp+Cams/249/1043-16/10002/-1. A full roller rocker would allow you to rev higher and thus make even more hp plus keep oil temps down. I have not done this yet to my 93 but want to in the future, I'm still researching this subject because there is a lot to think about before changing parts in the valve train, you want everything to work together or you will create problems. I'm sure others who know lots more on this than I do will comment. Good luck.

 

With full rollers Im guesing the stock valve covers cannot be used?
Car is not stock-I have a powerdyne bd-11a.
Also I read with 1.6 on the exhaust valve you can get a rough idle?
I plan on using LT4 valvesprings btw
Do the pushrods need to be changed?
Just did some more searching and have decided that I want to go with full roller. Can anyone recommend a good rocker?

 

http://www.compperformancegroupstore...e=SBCNEWRocker

These should fit your valve covers, you may have to do a little grinding to clearance them though. Also I'm not sure if these are self aligning or not, it doesn't say. If they are non self aligning you will also need to run guide plates and hardened push rods

 

Powerdyne eh? Guess this thread just took a left turn!

I'm thinking the ProMags might not work with centerbolt covers -- whether OEM or aftermarket.

Seems like people have had to use something like a Scorpion full-roller if they want to stay with stock covers and p-rods. Also consider whether you want to convert to hardened push-rods and non-self-aligning rockers. Those ProMags would require that swap. Very nice rockers though!



BTW,,,You don't need the Ultra Pro Mags. Plus, TomBrammer makes a VERY good point. If a head upgrade is in your future, 7/16" studs might be nice. OTOH, I don't think a 7/16" rocker is available in a narrow body or SA. If not, the conversion to non-aligning would definitely be required.

 

Should the factory 113s have guide plates?

 

Are the Scorpions any good? I was on their website and the 1.6s that are self aligning sound like a good product. Any downsides to self aligning?

 

self aligning can pop off the valve stem at high rpms, as long as you aren't spinning into the 6500+ range they should be fine

 

Thats good to hear-I definitely wont be spinning the engine that high especially with my TPI. lol

 

They come with something that looks like guide plates though they were used for assembly. They're not the same as guide plates for non-self-aligning setups. Neither are the push rods.

The Scorpions are good rockers. Pretty sure they're about the best reasonably-priced aluminum rr's you can buy.

 

I was on Scorpions website but it doesnt specify which are full roller or just roller tip.

 

on scorpions website under products all the rockers shown are full rollers the ones labeled "self-aligning" and "narrow body" should both fit with your centerbolt valve covers the only difference between the two is the one labeled "narrow body" is non self aligning and needs guide plates and hardened push rods

 

On your 1988 you want narrow self aligning scorpions. Go with 1.6 full RR's. Mine work great. Got mine at Flatlander Racing. Call them if you need help. I recommend strongly you get 101# LT4 spings from a GMPP online dealer.

 

Comp Pro Magnum sells a 1.6 RR kit that comes with new push rods. I installed a set in my 88. They are very quiet and add about 10 HP.

 

Crane suggests at least 105# seat pressure for full rollers- my CC 930 springs with stock seat pressure did not hold up. Some rockers came loose, a few slightly bent pushrods, but nothing major other than it taking me a while to figure it all out. I now have the CC 931 springs at 105#, and she runs way better. CC also took the 930 springs off their site, and they're not available from Jegs either.

 

You can use centerbolt valve covers (stock) with Pro Mags, but you'll have to modify them.
You have to remove drip tabs and grind some material of bolt guides. Easy job if you have air grinder.

 

Scorpions are excellent rocker arms. I'm running sets on my son's 96 LT1 and on my 388 LT1.

Jake

 

Not trying to hijack but I have a question that I hope someone can answer. I have Comp Cam pro mags 1.6 and want to change to a different valve cover. I like the proform 141-132 cover. Anyone know for sure if this will fit. Im not into modifying anything unless it's very minor.

Thanks

 

Just found the ones I need. Scorpions narrow body self aligning. SCP1036
Im going with 1.6 ratio and the set of 16 is $264.
How much do the LT4 valvesprings cost? Any vendors on here that sell them? Will my pushrods be fine or will I need to upgrade them?