83-84z28

OkI hope someone here can point me in theright direction. If you look at my sig. You can see my setup,well i went to the dyno last week and was not pleasantly surprised that i was only making 239hp and 281 lb.ft. my afr was abit rich at 10.5 but i still think i should be making more power than just 70 over my stockish lg4 i had before. I followed the tec article on distributor and am right in range throughout the range. I installed the cam straight up (dot to dot) The guys at work are knda pointing to poor cam selection and i sort of verified this when i called Patriot performance and they suggested a xe292 comp cam. Could this be a simple case of bad poor cam ? It just seems that th xe292 grind is a bit much for streetability. Any suggestions would be appreciated and any questions responded to. I would think i should have made around 300 to the wheel.

sofakingdom

iTrader: (1)

That's more than "a bit". That's like, not only not in the ballpark, but you're not even in the right area code. Your jets are around 25-30% too large in cross-sectional area. That's about 12% too large diameter (their number). That's BEYOND huge; that's MONSTROUSLY wrong.

How much did it improve when you fixed that?

What RPMs were the peak torque and HP at?

I disagree with just jamming a HUGE cam in that. Sure it might maybe make big HP #s, on the dyno; might even go fast at the track; but it won't be any fun to drive on the street. The cam you've got is a bit on the smallish side but should be fairly respectable.

I agree, the rest of your combo looks to me like it should put a good solid 300 HP to the wheels, once you get it tuned right.

83-84z28

At the time that i dyno'd it i had .101 jets and 070 X 047 rods in the primary and .095 secondary jets. I had mistakenly tried to copy the Eddy 1405 jets and rods to my 1806 (apparantly way off) The peak hp was at 5000 rpm and peak torque was at 3780 However as this was this engine's first run i probably let off a little earlier than i could have as it seemed to still be climbing when i let off. I havent re-dyno'd with the now stock jetting in it (.086 jets and 065 X 052 rods for the primary). so could i really be that far off power wise with this rich a jetting. Should i stick with the cam or go with something more aggressive?
BTW Thanks for the quick reply!

sofakingdom

iTrader: (1)

Stick with the cam you've got, at least for the meantime, and tune it.

It's going to be JUST as messed up with some other cam. Might as well get it dialed in, to where you're not trying fix multiple problems all at the same time (a fornicated carb, PLUS whatever a cam swap introduces).

YOu don't "need" a dyno run to tune it; if this is a Q-Jet, dial in the jets by removing the sec link and looking for best MPH over a long enough run to get all the way to 3rd gear. Use the same run every time and a stopwatch. Then dial in the rods by looking for the best acceleration time from something like 55 to 80 in 4th gear, at some high vacuum; like, tape your vacuum gauge to your windshield, and do your 55-80 run, at 12 in Hg or whatever other value seems most reasonable (the motor will tell you what that is, you'll see). With a Q-Jet, that is the proper technique.

Then once you get the primaries set up right, set the air valve tension for best MPH in the 1320'.

83-84z28

Sorry, and i know i'm going to get flamed i dont have a q-jet i've got an edelbrock 1806 (650 with vac. sec.). Everyone's been pushing me to get a holley or barry grant with mech. secondaries, and i will if needed ( i seem to be leaning that way anyway). Unfortunately i seem to be the victim of my own series of bad choices. I will try to tune everything as soon as i can. by the way my initial timing is at 14.5 and the vac advance puts in about 20 as does the centrifugal. The vac. adv. seems to come in at about 8-10" ported vacuum and the mechanical seems to be all in by about 2900 rpm.

sofakingdom

iTrader: (1)

Duh... yeah, not a Q-Jet, it's a Carter.... I guess my brain got a cramp and thought that model # was one of their Q-Jets.

Oh well, follow their instructions for calibrating it. I don't have anything to offer on those, they're just not something I've ever really dealt with very much.

But the same situation applies: swapping the cam isn't going to fix the carb.