Times, dyno and all mods listed in sig. Race weight was 3350 for the car plus about 280 for me.

 

Wow, more good numbers there. That's on completely stock heads? I thought the 847 was pretty beefy for stock heads. Maybe they do better with the higher lift cams then many people assume.

How was the driveability with that cam?

 

Water pump was stock. Stock 104k mile shortblock and 3.42-geared 10-bolt.
Car weighed 3550-ish I think. Made a lot of midrange, would tear the tires loose just about anywhere in the first 2 gears if you just rolled on the throttle.

 

My old cam only setup:

cc503, LT's, hooker catback, stock intake, stock tb, stock WP, 1.6 RR's, 2800 vigi, nitto DR's, full weight:

12.06 @ 112.81 MPH was my best run.. car would be anywhere b/w 12.2-12.3 @ 110 in average weather.

 

Completely stock heads. Car made 260 RWHP bone stock. Made 300 RWHP with Hooker LTs and CAI. Made 358 RWHP with the cam. Granted, when I say cam, I also mean supporting mods like hardened pushrods and 1.6 roller rockers. Some people think cam only means truly cam only. It made that power on a mail order madz28 tune, probably could have made another 5 - 6 with a true dyno tune. I'd say another 10 with an electric waterpump too. 847 is kind of a big cam, needs 4.10s, as car peaked around 5800ish if i remember, and best shift points were around 6700ish. Definitely need a stall for an auto, I'd say. With the 4.10s and it tuned, it had hardly any cam surge too. I've since sold the car, but my friend has the motor and trans in his 88 RX7 right now. Runs like a raped ape still. (wow that sounded redneck)

 

Thanks for the info, very helpful

I'm running a 6 speed car with 4.10s so I'm thinking the 847 will be perfect for it. Your post convinced me as I've just ordered the cam. What springs did you go with? Also what were you running for injectors and other fuel system?

 

That is too big of a cam for a 350.

 

why? what about with a built bottom end?


I'm going to be getting a semi "cam only" engine together. I'm not looking into setting any internet records, just personal, so I can't call it a true cam only car. waiting on the shortblock to come back from machining right now. stock rotating assembly fully balanced with ARP rod bolts, new piston rings, all new bearings, stuffed into a 4 bolt main block. heads are stock heads but milled a tad along with new valve seals. stock valves still. that, along with a slightly decked block and mr gasket head gaskets should put my compression ratio around 11.5:1-12:1 depending on where everything falls into place. I had Ed Curtis spec me a cam specifically for my car. ~250-300 lbs of weight reduction, 4.11s, yank PT4000 stall, 7,000 rpm red line and a goal of well into the 11s. I ended up with a 242/250 112 lsa with under .600" lift. I thought it was on the large side but he assured me it would rock from where my stall speed is all the way to 6,800 rpm so I am trusting him. rest of the valvetrain consists of morel billet link bar lifters, chromemoly pushrods, PAC1518 valvesprings, comp pro mags on 7/16" studs, and trickflow guideplates. I'm not cutting corners on this one. everything I know of in the book that will add power and help longevity I'll do. I see way too many people half-*** a car.

Back to my initial question at the beginning of my post. I know my cam is big but I specifically wanted it this way. my 383 had a 242/248 108lsa with lazier lobes and i loved it. the car is a drag car that can be street driven, not a street car that can be drag raced. Comparing it to a GM847 is interesting. while the .050" measurements are longer for my cam the specs at seat to seat are nearly the same. IVO opening is the same and IVC is actually 4 degrees sooner. Exhaust valve events are similar too. I don't have specs @ .200" lift to compare.

Seeing some of your guys times is pretty comforting to me in hoping to hit my goal. I would be ecstatic if I could run an 11.5 but I highly doubt it. maybe with a perfect tune, more weight out, and racing at atco or englishtown in the fall.

 

Well average power is what makes a car fast, and it will be down in that respect, and the rpms are going to be quite risky on a stock shortblock.

People look at advertized rpm ranges but ALL the big company aftermarket cam rpm ranges are way off whe used in an LT1. My best guess is they are applying gen 1 duration=rpm rules and neglecting the way the LT1 intake shifts the rpm range upward.

 

you're 100% correct. most people throw parts together. Hell I did it with my 383 and never had a chance to work the bugs out. with a GM847, 3.23 gears and a 2800 rpm stall it just won't work. this is why I'm running 4.11s and a PT4000 stall. I fully expect, with shift extensions, to operate in the 5500-6800 range for everything other than the launch, playing well into the average power range my cam should operate best at. If it doesn't work out I'll stick another cam in there. already have the stout valvetrain pieces which are the most expensive part of a cam swap.
As for the stock shortblock, most people won't take the time or don't have the money to freshen it up and ensure that it will last. I'm confident mine will run the next time I pull it out to put something a little more wild in its place.

 

I respectfully disagree that the 847 is too big of a cam for a 350, and over the years there has been much debate. While it will never be settled, I look at the only quantifiable measure (dyno results) as a way to compare. E.T.s and trap speed have too many variables, due to driver error, traction, and race weight. However, my car has been on 2 different dynojets, different models in fact, and dyno'd the same. I have compared my cam only dyno to NUMEROUS other cam only LT1s, and the 847 has CONSISTENTLY made MORE power and torque under the curve. Perhaps you will sacrifice about 20 ft. lbs below 3000 rpms, but in my book, if you begin a race below 3000 rpms, you need to learn to drive better.
My car made over 350 rwhp from 5400 to 6200 rpms. It made peak power of 358 at 5800. Ideal shift points are around 6700 - 6800. Some people consider this too high of an rpm for the LT1. I don't. I think its about the sweet spot, since the PCM limit is 7000 rpms. Why have it peak higher, if you can't rev past it? If your car makes peak power at 7000 rpms, the car will e.t. like it has LESS power than that, since you can't shfit past the peak, so it effectively never gets to USE all of the HP it can make.
Old farts think that the LT1 should rev to 6000 rpms max. Ok, then cam it for that. I think 6800 is better, so that's what I wanted to make use of.
There have been a VERY few examples of smaller cams making close to the same power as the 847, but it has been demonstrated time and again that the 847 makes 350-360 rwhp on stock heads. If 100 people have done the 847 and 90 get 360 rwhp, and 100 people did a CC305 and 20 got 350 rwhp, the odds of the 847 are more in your favor.
As far as 96capricemgr claiming average power will be down, it's just plain not true. I'll find the thread from a few years back where I believe JonA did a custom cam from Bret, and my 847 was nearly identical. No need to reinvent the wheel for a stock headed car.

Zigroid, I think the cam Ed spec'd out will ROCK. EdC knows his stuff. He spec'd out a cam for my buddy's 436 Windsor, and it made 525 RWHP N/A with out of the box heads. That car was a BLAST to drive.

 

Oh geez, I ran a set of single valvespring Comibination Motorsports, CM612 I think it was. I don't even think they sell them anymore. You'd be much better off running some beehives, though they are a good bit more expensive. I think they might even add a bit of power.

I was using stock injectors, which with a good set of 30s, it probably would have made some more power as duty cycle was around 103% at redline WOT IIRC. I also had a Walbro 255 lph in tank fuel pump.

I was also running nothing more than a stock replacement single roller timing chain. I'd love to have had a double roller though. I think I'd run one if I did it again. People say its a weak link, and I'm sure it is, but mine held up fine N/A and with a 150 shot. I think it's cheap insurance though.

Not sure how much you have read on doing cams, and I don't want to scare you, but there is one mod I STRONGLY recommend when doing a cam in an LT1. It is REAL cheap insurance, but VERY worth it.

I put a new STOCK oil pump with a GM White spring. The white spring is for higher pressure, which you will NEED turning the higher rpms. The LT1 oil pump is a cheap part, and the LAST thing you want is a ruined motor because of a $20 part. I've heard lots of stories of the oil pump pickup falling out of the pump, plus a new oil pump is a guarantee it will give you the pressure you need.

Good luck with it, and come back with some kick *** dyno numbers and e.t.s to prove to people how good that cam is!

 

No one thinks my #'s are real, but here is the graph...these #'s were NO SPRAY....





Car is a 1994 Z28, was M6 during the tuning.
355 stock rebuild bottom end,
Comp Cams 230/236 @.050 .555/.580 lift, 1.6 rr's, comp cams dual valve springs, gasket matched intake, 58mmtb, 30lb injectors, Walbro 315lph pump, slight bowl work done to the heads by Jordon Musser, Pacesetter LT's & custom ORY, custom CAI, A/C delete, electric wp.

and thats pretty much it.. car went 12.3@113 with 1.6 60' pulling front's 4" off the ground in 95* heat & 90+% humidity at Oreilly Raceway park..

and I'm sure Javier will jump on my case soon lol..

 

332/327 through a 2800 stall and 3.73 with 503 cam

 

Im loving some of the numbers Im seeing. Im new to LTxs, and didnt know a cam would wake them up like this.

Are there any good powerful cams that dont require a stall? Ive got mine apart, and figured I would cam it while I was in it, but dont want a stall yet.