I've been looking at a heads/cam upgrade for my daily driven stock bottom end c5. I was thinking of going with 62cc prc 220 heads + 228r cam, but I'm worried DCR is too high with that combo (I calculated 9.13:1 but that may be wrong). Going to 64cc still seems on the high side at 8.9:1. Car is a manual, and will be run on 93 octane. Any suggestions on a cam? I've seen the 228r recommended a lot for a daily driver, but maybe there are better options. I haven't gotten a ton of help from the couple of vendors I've contacted so far.

 

The Summit stage 2 cam or TSP 228/232 are better choices due to the larger exhaust split.

 

Make sure you are calculating DCR @ .006" instead of the cam cards .050"

The PRC 225 as-cast have 13* degree valves giving you more PTV clearance and better flow than the 20* degree PRC 220's

 

LS engines all have 15 degree valve angle. I think the PRC 220's are that or less.

 

Correct the PRC 220's are 15* and the PRC 225 are 13*
The 13* will allow a little more PTV

 

There are tons of cams out there that make great street cams. The main thing to look for is intake duration in the 226-229 range and exhaust in the 230-235 range. a few examples to look up:

Ed Curtis streetsweeper HT
Tick saturday night special torquemax
Cam motion Titan 4
TSP 228/232
BTR stage 2

There's tons of them out there, and the differences between them all are quite subtle. I can't say I've ever heard anyone complain about any of them.

 

Just pick what kind of heads you like, and then contact Pat G at PatGTuning and he will spec you a custom cam that cam motion or Texas speed will grind for you. You wont be disappointed and it will get you exactly where you want to be. Or follow Vaders advice he provided very good cams.

 

Yes. My concern is that when calculating DCR with common street cams I’ve been getting a high DCR value.

I redid it with the 228r specs at .006 as suggested above (used 277/277, 112lsa, 110icl) and got 11:1 static and 8.5 dynamic using sbe ls1 specs, 62cc heads, .051 head gasket.

If those numbers are correct that should be pretty good for 93 octane correct?

Could someone confirm those numbers.

 

I may do that. Thanks

 

I run 12to1 static compression and I have no problem with 93 octane gas. My car is fairly light 3000-3100lbs six speed with a 3.90 gear. Manual, low gear, light car will all play in your favor. Point being don't be afraid of 11 or 12to1 with a proper tune.

 

Yes, your numbers are correct.

On 93 octane, I will run DRC up to 8.73 on a daily driver. Track only, I'll push even higher into the 8.8's. I ran 8.56 DCR on 91 out in AZ heat for a few years with no issues on a daily driver. If you're set on that 228r, I would go to 61 or even 60.5cc on the heads tbh.

Also, be sure to run a thinner head gasket - .041. this will both raise compression AND reduce the detonation potential.

 

Great info, thanks. Just used the 228r because I had the specs handy.

Regarding thinner head gaskets, that’s to target a quench of .035 assuming a deck clearance of -.006 correct? I was under the impression from reading that actual deck clearance likely varies a little and without measuring I could end up with lower than .035 using a .041 gasket. Is that a major concern or not really?

 

The factory sbe is so much better than they were in days of eld. If you measure all of them, you'll find .003 variance across all 8 at the worst, unless you have bearing issues. If you're worried about it, measure them all and set HG by the highest off the deck. I've used different thicknesses on each bank before. but on a SBE that is not going to rev into the 7K+ range, I would not worry about it and would just rock a pair of .041's

 

Got it. Thanks for the help

 

I'm noticing a trend, that of using .041 gaskets to closely approach the magic .035 quench goal, after taking into account any negative deck clearance...