I'm thinking about getting into an ls1 next year and am looking for some opinions/facts on c5r heads. I know that sb2.2's are THE head to get for SBC's, bar none. I want to know if c5r's are THE head to get for ls1's, bar none. If anyone has a comparison of flow numbers or dyno numbers side by side, that would be outstanding. I want to know, ballpark, what a c5r-headed 382 with ls6 cam and LSX intake/90mmTB would put out at the flywheel. Also could it beat an SB2.2-headed 400 easily, or would the 400 run away from it. I know this is kind of vague, but it will be my first ls1 and I really don't want to put this kind of money into a car without knowing how it would stack up against the SBC competition. Thanks for any and all input in advance, I'm looking forward to seeing what an ls1 can offer me.

 

C5-R heads need a custom intake. No LS series intake will bolt up without modification of some nature. They have very small chambers as well. C5-R, ETP, and LS7 are probably the top of the LS series pile right now.

 

ttt

 

My understanding is that a C5R head wont work on a 3.900 bore.

 

That's what I was going to add.

You'll need at least a 4.125 bore as most of the C5R heads get put together with a 2.15 or bigger valve.
ET uses a 2.18 valve on their version.
Mine is a 2.225 In.

As far as manifolds go, the port design on the intake side looks identical to the new LS7 castings which might work with the new LS7 intake manifold.
But I cannot confirm this, not to mention the flow capabilities of the head will probably exceed what the LS7 manifold can do.
My Hogan manifold uses a 4" runner built specifically for use above the 5500-6000 rpm range.
My heads also flow well over 400 cfm on the intake side at .800 lift.

If you don't plan on big rpm and a massive cam, there is probably a better choice of head for the LSx series that will be alot cheaper.

 

I agree with the above.

Also, why would you think about pairing an anemic cam with a full-race head? You'd make more power with a ported LS1 head and a bigger hydaulic roller.

Mike

 

My original intent was to get a side-by-side comparison of sb2.2 vs c5r heads, with flow numbers for each. If it would be more cost-effective to get a different head and make comparable power, I would be all over it, but I am curious about if c5r's are the final word in ls1 performance heads. I know Patriot and AFR make nice affordable heads and I'll probably end up with one of those, but curiosity has bit me pretty hard after reading what some c5r-headed engines are doing. Recently Shafiroff advertised a $2995 382 that looked really tempting and 405hp Z06 cams look impressive and affordable, so that was the basis for my hypothetical engine. I don't even have the ls1 car yet, so I was just asking some questions. Keep the feedback coming, as I can use all the ls1 info I can get from people who have actually used these parts. Thanks.

 

Let's just point this out again. You will NOT be able to use the C5R heads on a 382. The valves are to large, along with the port volumes. The combustion chambers are also to small. A set of ET performance 215 cc 11* heads and a Z06 cam would work nicely in a stock bottom end, although I prefer more camshaft than that. If you would like to look at flow numbers, go to www.etheads.com and check out all that they have avalible. They have C5R and brodix versions I believe.

 

Does anyone here have dyno numbers on a ls6 with nothing more than a 382
stroker kit and possibly some good heads? That could at least give me a baseline as to how much more than 405 hp these upgrades will offer total, and would help greatly in determining where to spend the money. I'm just about dead set on the stroker kit and cam due to their affordability, but I would really appreciate the hp comparison for the upgraded heads.

basically: ls6=405hp, 382 ls6 w/ stock heads=?(ballpark), 382 ls6 w/ upgraded heads=?(ballpark)

Thanks a lot in advance for whatever info you can offer.

 

You heads and cam selection play a HUGE part in power.

These are my choices for a stroker motor:
Dart 225s or AFR 225s or seriously ported LS6s.

The cam would be somewhere in the 240 duration @ .050" with .600+ lift.

You then of course would want to buy a FAST 90/90 TB/Intake Manifold Setup, some 42# injectors, possibly some new lifters (Morel if you have the money....not a necessity, though..the Melling stock replacements work fine), possibly new rockers (Jesel if you have the money, stock if you're on a budget) and dyno tuning. Don' forget all of the necessary bolt-ons like an Underdrive crank pulley, Longtube Headers (Get the LG Mototsports if you have a Vette), Exhaust, CAI, etc, etc, etc.

If you want roundabout numbers at the crank, then:
z06=405
382 stroker with ls6 heads = somewhere around 460 (around 400rwhp w/manual)
382 with aftermarket or ported LS6 heads = anywhere from 500-650hp (430-550rwhp w/manual)

Mike