[UPDATE]

I left the rest of the initial post intact, but so ppl dont have to read the thread before replying, here is what I'm currently planning:

CC503 cam
MSD Opti
Meziere 55gpm WP
160* T-stat
Cloyes Tru-Roller timing chain
918 Beehive springs
787 retainers
648 locks
Oil pan gasket (any recommendations Jimi?)
Timing cover seals
New timing cover for mechanical WP delete (I need this, right?)

[/UPDATE]


So I think I'm gonna finally take the plunge this summer and put a Hot Cam in my LT4. So while researching the installation procedure, I got to thinking about the things I might as well replace while I'm in there. Here's what I'm thinking so far, but I could use some help. I've got LT headers/cats/Corsa as far as performance mods go, and some AFR heads are being considered as part of the operation...

1) Meziere water pump
2) 1.7 rockers
3) Lightweight pushrods (worth it?)
4) Maybe, MAYBE, a set of 195cc AFR heads


So my question(s) is(are):

1-My Opti is still doing fine at 75k miles; should I replace it while I'm in there, or would it be wasted money?
2-What 1.7 ratio roller-rockers would be best? Also, I think this would be beneficial power-wise, especially with new heads, but what about on stock LT4 heads/intake? Also, would I need to get any additional hardware with the rockers? Like guidplates or stuff like that.
3-Like I said above, is a new set of pushrods worth it?
4-Lastly, how big of an ordeal is it to change the heads?

I know this stuff has probably been answered many times,but one of the things I'm concerned about is the "whole picture" deal of the engine, and making sure it all works together well. I will be getting it dyno-tuned at Tony's Corvette Shop in MD soon after the work is done to optimize everything, so the tune shouldn't be an issue.

 

Since you are planning on replacing the rockers and rocker studs why not get 7/16" non self-aligning rockers, guide plates, and hardened pushrods. Not sure about the 1.7 rockers. But, I like TrickFlow Chromemoly pushrods and guide plates. ARP rocker studs are very high quality also.

If you are wanting more lift than the HotCam, why not use 1.6 rockers and get a custom cam or at least one ground with more lift?

 

Good point. Now that I think about it, I've heard good things about the Comp Camps 503 grind. Only problem is that I recall there being too much lift for the stock LT4 valve springs, so those have to be replace with heavier replacements. Guess I'll add that to the list.

So assuming I keep the rocker arms and pushrods and go with the CC503, what valve springs should I get?

 

I too am considering this down the road. From what I've found, going to the 1.7 rollers is a definite plus. Everything I've found leads to Scorpion. You will need guide plates as these are not self aligning. Push rods and springs are a safe bet as well. My concern with the hotcam roller combo that I haven't found out yet is piston clearance. It would really suck if a piston hit the valve.

I do know that if/when I do this, I will definitely replace the opti, either up grade or just a new stock one. If no other reason just b/c I wouldn't want to have to take all that stuff off again for a while. Coil, ignition, and wires. Perhaps upgrade timing chain. Maybe even consider underdrive pulley.

 

You will definately need new springs if you do the HotCam with 1.7 rockers or the Comp 503. I like the comp 918 bee hive springs.

You won't have any piston to valve clearance issues with either of these cams.

 

I would seriously consider replacing the opti. I would upgrade to the MSD pro billet opti. While your in there might as well install the end-all of optis.

 

I'll look into pricing for the Opti. I'm not sure if I could stomach both heads and a new Opti, so I might have to make a decision there

Looking into cams, rocker arms and springs, I think what I'm going to go with is the CC503 with those 918 Comp Cams valve springs. Should I get the recommended 772 or 788 retainers with them? I'm not sure about all the little stuff

 

I'm using the 787 steel retainers with my 918's. In bee hive retainers the steel is about the same weight as the Ti's, and more durable. Also using 648 locks.

 

There was a bad batch of comp beehive springs a while back. Not sure if they fixed the problem. They were breaking causing major problems. Many people have switched over to the PAC springs because of this. Do a search on the Z28 forum if you want to read about it. There are also several threads regarding the 1.6 vs 1.7 rockers. I remember reading that the 1.7 may not be worth the extra effort if you are doing the cam anyway. There are a few companies such as Ai that sell custom cam kits with everything included.

 

Get a quote from epowershops.com for the MSD opti.

 

Based upon my experience installing the hotcam. . . .
I would definitely go through the extra little effort and put a high quality oil pan gasket on there. Clean both front and back ends of the intake manfold till they are squeaking clean. . . then use the highest quality silicone high temp sealant that you find. I used the RED high temp silicone from permatex. Get a lower temp thermostat, 160 if you can find it. Clean the IAC throughly. With the stouter cam, you gonna trigger a misfire code at idle. I dont remember the fix, but it is here somewhere on the forum. Hope that helps some. Good luck

 

If you're really thinking about replacing the heads as well as the cam in your LT4 why not consider checking out Lloyd Elliot. He specializes in LT1/LT4 head/cam packages.

lloyd elliot's website is www.eportworks.com


Also you might want to consider replacing the lifters even if you stay with your stock pushrods.

 

Thanks a lot for the pointers guys (or gals).

At this point, I think I'm gonna stick with my stock heads. The LT4's don't flow too badly, and I think that a head change may be more than I want to bite off for this project. I'll have to look into the quality control on the beehive springs, that's strange.

JimiHendrix: I've had my intake manifold off now twice replacing the gasket trying to fix my high idle. Finally figured out that the "LT4" gaskets they sell don't actually fit, and I have to buy the $30 ones off Summit and spend half an hour dremel'ing the ports to fit So I know about cleaning the intake and sealing the front/back.

So as of now it's looking like:

CC503 cam
MSD Opti
Meziere 55gpm WP
160* T-stat
Cloyes Tru-Roller timing chain
918 Beehive springs
787 retainers
648 locks
Oil pan gasket (any recommendations Jimi?)

 

Think about replacing all of the seals in the timing cover, i.e. crank, WP & Opti drives.

I have the opposite problem... a small crank seal (maybe?) leak leading me to wonder about taking the cam plunge.

 

Yeah, I definitely will do that. Also, I need a new timing cover, right? One with the hole for the WP plugged?

 

Good luck on your build. Keep us up to date. My previous mods where similar to what you are doing (I did the LT4 top end with hotcam, LT headers Mez water pump ETC. ETC.) And I was very happy with the power. Even more so now that I did the 383.

You will be on par with most of todays performace cars.

 

The power is in the heads.

 

Felpro has a heavy duty one piece gasket that is virtually leak-proof. It is blue in color, and very stout piece. Most auto stores have it. You install it dry.

good luck

 

Nice. That's the one I was looking at once you recommended replacing the gasket, so it's already on the list

I think the only thing remaining is which Tru-Roller timing set to get? There are like 20 different ones for the SBC. And what to do about the timing cover? Do I need to buy a new one?

 

You can't Buy a timing cover with the WP hole plugged, you'll have plug your own.