Hey all,

I just took my Camaro up to the new chassis dyno at a friend's shop in Binghamton, NY. If anyone is in the area, hit up Overdrive Automotive in Johnson City to check it out. Anyway, the numbers came back nearly exactly where they should have for my setup - 349whp/373wtq - I'm very happy with the numbers.

That said, I'm always interested in more power. Take a look at the dyno video and the dyno sheet below and the specs of the build. I think that I'm choking my heads off before they are able to breath completely up to 6500. The XE274 cam in it goes to 6000 (the dyno sheet shows about 5800 but I think it's off a couple hundred RPM) while the heads go up to 6500. Is there perhaps a better cam combination to throw in this thing to glean a bit more top end?



• 360cu, 2 piece rear main, 4 bolt, ARP hardware intake to oil pan
• 11.2:1 static compression, 93 octane
• Speedpro domed hypereutectic domed pistons with valve reliefs; -11.8cc volume
• Holley 650 mechanical double pumper, Holley HP main body (choke delete, high flow, 750 conversion, 1” phelonic spacer)
• Edelbrock RPM Air-Gap
• JEG’s (Profiler rebranded) aluminum heads, 195cc intake, 72cc combustion chamber, 2.02/1.60 intake/exhaust ports, screw in studs with guide plates, angle plug, D-shape exhaust ports
• Comp Cams High Energy 1.5 full aluminum roller rockers
• Comp Cams Magnum pushrods, hardened, 5/16 diameter, 7.900” (+.100”)
• Cometic MLS head gaskets, .051” quench
• Comp Cams XE274 camshaft, hydraulic flat tappet, 1,800 to 6,000 rpm, 230/236 duration at .050”, .490/.490 valve lift
• Proform GM licensed die-cast aluminum valve covers
• MSD E-Curve distributor
• MSD Digital 6A ignition box
• MSD Blaster 3 coil

 

http://www.crankshaftcoalition.com/w..._compatibility

You didn't say anything about the exhaust.

 

1 5/8" primary, 3" collector, long tubes, true dual straight pipes.

 

Pretty reasonable numbers. I would do a roller cam conversion to get a more aggressive lobe with lots more lift. Duration you should be good to pull to 6500 but need abit more lift to breathe up top. Roller cam will give you lift with that same duration but a faster lobe to keep good driveability. Going much bigger with a flat tappet is going to start making bottom end soggy and idle abit rough

 

I've been toying with a roller cam conversion for awhile. I'll have to double check my piston/valve clearance to see how much more lift I can get away with. Any ballpark ideas on how much more on the dyno I would see out of a roller setup?

 

Something like the xfi 280 would make closer to 360-380 whp if the manifold and carb arent holding it back. Thats my guess with those heads box stock. I tuned a low comp efi 360 with that 280 cam on old afr 190's and it would have made 350-360 if it didnt suffer valve float. Springs are crucial for that cam. Need a stiff double. Your heads are on par if not beyond old afr 195's. same valve size. Definately revs out 6400-6500 rpm. Alittle head work and it could see 400 whp. You reallly get smoother operation and should see more low grunt from faster lobes. Abit smoother idle but with carb you may want to change lsa on most shelf cams to 108-111 depending

 

I smell winter project.

 

Its worth a shot imo. No worries about oils and lifter/cam lobe failures, etc. as long as valvetrain is there to support the rpm and roller cam lobe i think they are superior

 

How much advance were you able to get away with?

 

It's fine. You're not going to make peak HP at 6500 with that combo- that would take a much larger cam, and I doubt you'll like living with anything much bigger (on the street anyway). In the real world, you're going to shift at a point beyond peak HP anyway. I suspect you'll find your best ET shifting right around 6500 or so.

Anything is do-able for money, of course, but you built a nice stout little 350. I'd think long and hard about swapping all sorts of parts for a few more HP- go have some fun with it first, then decide a COMPREHENSIVE plan of action.

I would tell you to add a nitrous kit for those times when you really need to turn the amp up to 11, but with that compression ratio I wouldn't try it on pump gas. Just too risky. And with hypereutectic pistons..... nah, just keep it the way it is.

 

Sweet car. I hope mine looks as good when done.
Great numbers too.

BTW what size rims are those? the cast 15" or 16" iroc rims?

 

I agree with all points made. I know that as far as tuning goes, the car does need a good tune. That being said the dyno day was essentially just to get a baseline for me, which yielded results I was not anticipating. My engine builder was also there as he had 4 other cars there that day and was shocked at the numbers mine put down. He was expecting them to be low as there was no tune in the car at all, but the numbers that came out were baffling to him as well. Exact same build as a one he did for a corvette with the exception of the headers, and that car made a consistent 420 to the tires on the same dyno.

I know there's work to be done, and the point of this thread wasn't to start a pissing match about anything, but to see if the dyno numbers I gave were expected given the info on the car at hand...

General consensus seems to be that they're pretty in line with each other, as unfortunate and disappointing they may be.

 

I wouldnt go any bigger as said wiht FT cam
Those heads pick up a lot with minor work if Im not mistaken. If done correctly you could sacrifice only a few cfm on runner size and pick up a solid 30+cfm.
If you went roller on top now youre talking.
You got a solid 350 right there Id leave it as is unless youre really unhappy the $/gains really take a leap from where youre at.

Unless I misread the same combo going 420 at the tire, not possible

 

Thread is over 6 years old guys and the OP hasn't been here in over a year.