Modified P75 Head vs Stock B16 Head, which one?

Seems like a hell of a choice to make, and that there should be one obvious answer, but the complication is because of the specs below. I have in my possession these two heads, and will mate one to the block listed below. Ignoring the circumstance of why I'm doing this or how I got into this choice, which head would produce more power? The engine will not be a street engine, and will see not see any drag racing. It's goal in life will be to power an endurance racing CRX.

I'm looking to get some informed opinions. I know there is a lot of speculation and heresay here, but I would appreciate anyone with first hand knowledge chiming in. I have done a search through the forums of which head flows better, but I've found nothing but speculation from "friends of friends that once heard this" And yes, I did say I was looking for opinions because its likely no one has had this comparison come up before so I don't expect anyone to come up with anything definitive. I'm looking for a rough educated reasoning as to which would be the better choice.

Thanks in advance to anyone that can help.

Modified B18 P75 non-VTEC Head
Brian Crower B18a1 stage 2 cams, BC0022
Brian Crower 31mm valves, BC3020
Brian Crower 28mm exhaust valves, BC3021
Supertech dual valve springs and titanium retainer kit, SPRK-TS1015/LS
Lightly resurfaced head (approx 2mm remaining)
3 angle valve job
No porting/polish work

Mostly Stock B16 PR3 VTEC Head
Skunk2 Stage 1 Cams
Lightly resurfaced head
3 angle valve job
OEM 33mm intake valves
OEM 28mm exhaust
OEM everything else
No porting/polish work

Modified B18 Block
Eagle forged crank, CRS1835041772
Wiseco pistons (altered height, 9.8:1, 81mm bore), K542M81
Wiseco rings (30deg offset installation), 8100XX
Molnar rods, HH5394CEB4-A
Arp head studs, 208-4302
Arp rod bolts, 208-6001
Rehoned cylinders

ECU
Hondata S300v2

 

unless your goal is to do it non vtec "just because you can," the correct answer is the b16 head.

 

Thanks for the follow up to my question. Could you explain what makes it the "correct answer"?

 

Later when I'm at my computer... Didn't feel like typing up a long answer on my phone

 

The b16 head flows 100x better than a stock port p75 head. Even a ported p75 head can't really compete as well vs a vtec head. They make way more power. You'll NEVER make the kind of power nonvtec as you can vtec. It just won't happen N/A

also, you can retain streetability a lot better with vtec. Nonvtec with big cams is like having a vtec head with vtec killer cams. (vtec all the time)

 

The key word I see in your build spec is "endurance racing" what you want is reliable, usable power.

I'd do the b16 head here without question. It's damn near bulletproof, it flows about as good as you're gonna get for a stock head, and the parts support is better. Having vtec will be useful, there will be slow corners where you'll have to drop the revs down and you'll have the low cam to keep some usable torque down there. The non vtec head is going to have a narrower power band and you would fall off the cam in those scenarios. Even with port work it's also going to flow less at the big end then a vtec head would. The b16 head will still make more power in the higher range where you will spend the bulk f your time, assuming your gear strategy is on point.

If you really want to do a non vtec head, seek out a P8R. It has 33mm intake valves as opposed to he 31s in a P75 head and also has 84mm combustion chambers that leave the valves much more ushrouded (with room to improve with a little work). I'm not a huge fan of the rocker design on these heads though, and the valve seats have a tendency to recess on the exhaust side. For that reason and others, forget the Supertech springs on that head, they are very aggressive and have a ton of seat pressure and are honestly wayyy more than you need for the cams you listed. Rocket sells a set that are much lighter and more ideal for that application. Skip the Ti retainers and stay with steel. The Ti will wear out quickly and I wouldn't recommended them for anything that is expected to see sustained rpm.

For either, consider putting more effort into your engine management. AEM infinity with COP would be the way to go in my opinion and leaves you a ton of room to grow. There's a ton of drivability and efficiency (longer stints!) on the table for your application if you put the smarts into your electronics.

You really need to consider reliability more than power for a build like this. Enduro is a far different and harsher environment than a street/strip build will see. What are your plans for the bottom end?

My $.02, lol

 

How much of an influence does the the cam have versus valve size? I know that the B16 has 33mm intake valves versus the 31mm on the p75. Are you saying that even with aggressive cams on the p75, that the larger ports of he B16 are what makes the difference? Since we are looking for more flow through the motor, is the port size the more influential feature was?

 

Good points. The narrower power band would be a difficult to manage for the lesser experienced members of our team.

I asked of this in a reply to the previous post before yours, but can't a more aggressive cam with small ports make up for a less aggressive cam with larger ports?

My plans for the bottom end are what is listed in my original post. I actually have all the parts I listed. Went on a buying spree and ended up with this stuff pretty cheap, but now that I have it all, I'm trying to decide which pieces would be best. Shopping the forums I got all the stuff above for under $2000 including 2 transmissions and a stock b16 bottom end.