correction, i meant to say a GM 847 w 1/7RRs, or a custom cam like .620/.630 with a long *** duration on a 110 or something along those lines

 

correction, i meant to say a GM 847 w 1/7RRs, or a custom cam like .620/.630 with a long *** duration on a 110 or something along those lines

 

You are defiantly way down on power. How was you knock? Was it dyno tuned or just dyno tested? I would think something is missing here. Do you have a logger? What kind of injectors etc are you runnig? How high did you spin the cam to make that power?

I have a 355 with a 847 and stock ported castings and im well above your 396 in the HP range.

 

Very little knock and it was dyno tuned. I'm running 37lbs injectors and we spun it to 6500rpm.

 

Your numbers sound ok to me. You can't build a 383 or 396 and put the same top end that would make 380 rwhp on a 355 and expect it to significantly increase the horsepower output on a larger cubic in motor.

I also do not think you'll pick up 70-100 rwhp as was talked about before unless you go with some nasty solid roller cam, and even then I think the heads are still going to limit you (not saying your heads are bad, you just need more cfm for the extra cubes.

 

What are your goals for the car? I think your number are fine for the combination. Your torque numbers are great and I think it would make a great street/strip motor. I bet that thing drives like a monster on the street, you don't have to spin in to the moon to make power, and it will give you miles of smiles.

Also look at your graph and check the areas under the curve. I bet your torque is nice and flat and you hp is not at all "peaky". I don't hold a lot of faith in dyno numbers anymore as my car with a cam "way too small" for people on this board put rwhp numbers all over the place 362, 385, 400 on different, yet supposedly repeatable dyno jets..I ran a Corvette with 466 supposed rwhp and beat him at the track. As long as your tune is right, your graph looks good and your tuner found nothing glaringly wrong I say hit the track and see how that torque moves that car! Dynos are a great tuning tool, but the track is the ultimate judge...Sounds like a fun ride...

--Alan

 

Something is definitely wrong. The cc306 can make up to 400rwp on stock ported castings in a 350. Its made over 350rwp on stock UNPORTED castings in an otherwise stock 350. I would look into things like rocker adjustment, optispark. It may even be the dyno, would be good to see what other cars are putting down on that dyno. Try to find out if you can get the flow numbers on your heads from mti.

 

when running an auto and a 12 bolt its hard to tell what kind of power you are losing through the drivetrain.

i think its funny that most people on this board will tell you that the 306 is too small but that cam can make over 400 rwhp. however, it depends on the whole setup and not just the cam. the better the heads you have, the less cam you can get away with and vice versa. the mti car that i was referring to did have an lt4 top end, but that still leads to my point that the 306 can make plenty of power with the correct combination. if your heads arent really that good (ported lt1's in the 270 peak cfm range) then you can over cam the motor and you will make more power, but you will sacrifice drivability. with a 306 in a 396 motor, it probably sounds real mean but drives like stock. i think you should take the car to the track and see what it runs. that should mean more than your dyno numbers.

 

the 847 would be a mild cam for a 396 with good heads/intake. About like having a hotcam in a stock cubed lt1 (which produces some great results I might add). I had the 847 on my stock cubed lt1 w/1.7RRs for a year or so, nice combo for a stock engine/heads, but would think a solid roller custom grind cam would be best.

 

well you guys are all wrong about the head flow numbers not enough to support big numbers with a solid roller

here are xxsaint69xx head flow numbers very close to mine

Flow Numbers:
.200---149.8--111.5
.300---207.4--143.0
.400---247.3--162.5
.500---278.5--179.8
.600---289.5--190.0
.650---288.5--193.9

MTI LT1 heads. Big Valves, Tripple Coil Springs good up to 700 lift. Big Valves, ARP 7/16 Studs.
2.02/1.60 i believe. Flow sheet for the heads is bellow, i have the actual sheet as well so the numbers arent fake. Awsome head. Motor made 622/735

Custom Solid Roller Cam for the heads by Lazer Cams. 254/261 duration, .678/.678 lift with 1.6 Rockers. 114 lsa.

 

622/735. Cool. You da man!

 

Huh?!

 

with a 200 shot lol but here is what 1racerdude wrote me




I made a run through with the same cam that ran 10.30's with a 383 and a turbo 350.

Your combo made a peak of 617 FWHP@7000 and 517FWTQ@5500 that equates to 505RWHP with 10.8 inches of vacuum that will be enough to run power brakes.

Ain't done yet---the torque seems to be low-- going to watch the game.



Larry

 

~500rwhp on a 200 shot in a 398ci...not bad I'd say!!!!!!!!

So that's like...310-315rwhp N/A?

 

Don't know about a 200 shot.Must be another engine.

The numbers I gave him were ALL MOTOR with my camshaft in it.