disappointing 402 with L92's
 

I just dynoed my car today, very disappointed. It made 403 RWHP and 415 RWTQ. It has unported L92's, an L76 intake and a 228/230 on a 112 cam with 585/585. It made max power at 5600 rpm's and had 88 kpa at max power. I don't understand how people are putting up close to 500 rwhp with an L76/LS3 manifold when I'm pulling this much vacuum at 5600 rpm's, I have an LSXR intake that i'm going to put on and return to the dyno. Do I just have the wrong cam?

From what I've seen, the L92's seem to like a larger split in duration vs. what you are running.. Specs on your cam are identical to my old Trickflow stage 3 cam.. IMO you not taking full advantage of your set up with that cam and would get with Geoff at EPS or Pat G.

Yeah, I've heard that, but I thought there was a guy a few months back that posted on here with a set up very similar to mine that made 460 rwhp?

What ICL was the cam degree'd in at? Also what was the barometric pressure in kpa?

I'm not sure I know what ICL is, if your asking if the cam was installed straight up, then yes. If you're talking about the pressure in the manifold, it registered 88 KPA at 5600 rpm's. Did I answer your questions correctly?

Minus 2 degrees was ground in and the cam was installed straight up.

I'm at 2500' elevation, atmospheric pressure is usually around 95-96 kpa, sea level is around 100 kpa. You could be at 4000' and your atmospheric pressure could only be 88 kpa. No way to know how much of a restriction there is without knowing basline kpa. Get a degree wheel on that thing and check your cam timing events isntead of installing "straight up". How much lifter preload? Also what springs are you running and what condition are they in?

My 402ci 11.0.1 comp,ported l92's,stock l76 m6 12 bolt 4.11's made 517hp @6,300 468tq. @5,400. The cam at the time was 248/254 112 620ish lift on a 112 lob. I then went to a new cam from a vendor here and went down to just under 500hp with a lot of work and cutout open. I then went to the victor jr intake with elbow and a CUSTOM CAM FOR THE L92'S FROM PAT G. I told him i wanted the cam to pull high in the rpm's and it did pull to 7,500. from 7,000 to 7,500 it only lost 9hp. i then went to 530hp @6,900 rpm's. My new cam is some smaller and drives better. You should still be able to get close to 500hp with a proper set up. You do have some issues going on there. who installed the cam?

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I only got 423rwhp and 465rwtq on my 402 but I think Im being restricted by the ported 853s. Im looking to get a set of L92s and hopefully that will get me to 480rwhp.

I live in Ohio, which I believe is about at sea level. I have manley stainless valves patriot platinum springs (good to .700 lift) and titanium retainers.Stock length Trick Flow pushrods and Caddy lifters. I have revved this thing to 7,200 with no valve float. I have stock injectors which hit about 95% duty cycle at max rpm. Does anyone have a recommendation on a mild street cam that will get me to 460 to 480 h.p.?

l92's suck.lol they are a lazy head and hard to cam for most. I wish i just bought trick flows 235's back when i was going to. But,lucky for us trick flow has a l92/'ls3 head coming out end of the year. I hear it is a killer head. i talked to ed at trick flow. they shrunk the large intake valve down and i believe it's a 11 or 11.5 deg head and flows like a 245 head. can't wait to see what it will do.
LOROLLR-Get with Pat G on this site.

Mike C., a local guy that does nothing but ls motors installed it, I've known him for a long time and he has built some really killer motors, but this is the first ls3 headed one so we are learning together. The TFS's sound Bad Azz!

There is no way that cam is causing that issue. Are you sure your exhaust is not restricted? Cats plugged, crushed Y pipe? What TB?

OP you might want to PM WKMCD. He just had a 427 done with L92's. Maybe he'd be willing to share some info in PM. Not sure but its worth a shot. His 427 made a mere 576 rwhp 530 rwtq, and drives like STOCK ! Hope he can give you some pointers. Best of luck finding all that missing power.

Heck buy his old JT cam off him, it made 521 rwhp form a 402 I believe.

There is more going on than the cam, peaking at 5600 and the 88 kPa is the issue.

My buds car peaked at 5,800 and down on power.It turned out to be valve train. it now peaks at 6,600 and went up like 30hp.

i have 1.75 pacesetters and dual 3 inch with an h pipe. My car is a 1965 gto and the headers are for a newer truck, the passenger side dropped right in, but the driver side had to be cut and welded on 2 of the tubes. they don't look too hot, could be restricted, maybe that's what it is. That doesn't explain the vacuum in the intake though.

Double check your pushrod length too

what is the intake/exhaust valves sizes? and what the intake/exhaust runners sizes of the new TFS LS3 head?

Or mine that is a stock LS2....

Like 69 said....

There is something else going on.

Who built the block? Did you mill the heads? Run a compression test? What gasket? Pushrod length? What tb and is the intake ported? Who tuned it? What gas? What's your afr? How much timing?