87silverbullet

iTrader: (11)

I had a 406 built with a ton load of good parts but one thing that has bothered me is the 5.700 rods in it. I know that it will cause side load issues and affect cylinder walls and piston skirts.

Will it affect longevity down the road of the motor? I am also wondering if there is more power to be had with a 6.0 rod in the motor.

The motor dyno'd 565hp on an engine dyno on pump gas. We were hoping to hit the 600 mark but I think 565 isn't too shabby on pump fuel.

I think the heads are holding it back a little but we wanted to keep it with some low end torque since it is a street engine. It has AFR 210 Eliminators on it that are fully cnc ported.

Oldsmobility85

iTrader: (1)

It should do fine with 5.7's. 6.0 is about the standard though and probably would make a few more hp. I wouldn't worry with that. The 600 mark is probably more achievable with more rpm such as more camshaft and valvetrain and intake manifold.

How much torque did it make? What kind of rpm range did it make peak hp at?

87silverbullet

iTrader: (11)

The cam is already pretty big. 268/274 636/648 on a 106. It has a T&D shaft system for rockers and a solid roller setup. The intake manifold is a ported super vic. Believe it or not it made the most power with a cheap 830 cfm Holley carb staight out of Jegs. We tried a 1050,650,750,and a 790. Made the best power with the 830 torque and hp wise. The dyno guy was bragging about this carb he had that cost him 1200 bucks that he had modified and when we put it on the motor and made a pulls and tuned it, it only made 3 hp over the $400 830cfm carb.

I will have to pull the dyno sheets out to find those numbers again. I don't remember where it made the peak torque and how it carried the hp.

pancherj

565 seems low for what you are working with. Tell us more about the combo...

manifold?
timing curve?
headers?
measured compression?
curves from the dyno pulls?

Paul Huryk

Before the 6" rod & piston combo became widely available most everyone used the 5.7" 350 rods in their builds - built right not too many problems are going to happen.

That is a big cam - my cousin built a 406 for his Camaro back in 1994 that made 514hp @ 5800 with AFR 195s and a 230 cam (.550 lift) on a 110. That motor used 6" rods.

87silverbullet

iTrader: (11)

Super vic manifold cleaned up and port matched, not really ported out. I should of said that in my previous post. Just like any traditional pump gas smallblock it liked 36 total timing. The headers used on the dyno were just dyno headers but I think they were 1 3/4 headers primaries. We have 1 7/8 headers for the car its going in. The compression did not come out where we wanted it because we ordered the wrong pistons and we just told the engine builder to go with it and it came out to like 11.3:1. Like I said earlier, I would have to get to the dyno sheets after work today because we dyno'd this motor a year ago and I don't remember everything. So many things have come up that we haven't been able to put it in the car.



See, there you go, He has a 6.0 rod and made good power. Thats what makes me wonder about the 5.7's in mine. If he had a bigger cam it would of maybe carried it higher in the rpms and made more power but he only has 195's so it might have been airflow limited but we are talking about AFR's here

The cam was spec'd by our engine builder who is a graduate of Mondello Head porting school and with the help of one of the guys he knows that works at Comp cams. The thing is though we had it spec'd for the original set-up that was supposed to be higher compression but we ordered the wrong pistons.

pancherj

I had a 406 built with stock rods, crank and old TRW pistons. Compression was 10:1, cam was a solid flat tappet with similar specs (less lift), ported Twisted Wedge heads and a victor Jr. with a 750 double pumper. It was making right around 485HP and I was shifting at 6500 (and it was still pulling). I don't think 6" rods has anything to do with it. I also think you are right for expecting more power. I also can't believe a larger carb didn't bring more power and RPM. Where did the power and torque peak?

pancherj

Found this posted on Chevelles.com...410" 4.145"x3.800, Mahle flat tops, about 11.9-1 comp., old AFR 210's by Dr.J's, Isky RR615 roller, Super Victor by Dr. J's w/975 Demon. Driven to the track regularly. Best E.T. so far 6.48/104. Best with soft nitrous tune 6.11/112.89.

I couldn't get the graph to post. It made 615HP at 6800RPM and 545ft-lbs at 5400RPM. I think you should be "similar".

Oldsmobility85

iTrader: (1)

Thats cool man. I would have liked to see 600hp also. A 400 pulling 6800 or better rpm should make 600hp.

How much compression are you running?

pancherj

My 406 is long gone. I run a peanut motor now (350). It makes close to 485HP with 10.8:1 compression (pump gas), ported AFR's, 240@.050 hydraulic roller, ported air gap and a 750 mighty demon. I shift at 6800-7000RPM.

Get the engine in the car and run it down the strip. That will tell you a lot....and it is more fun then bench racing!

87silverbullet

iTrader: (11)

The larger carb did bring more hp but not much more. It lost torque bad though. So I rather lose a lil hp than alot of torque.

You could hear it on the dyno too. The smaller carbs were snappy on the dyno and when the dyno loaded the motor it came right out of the bog down. With the bigger carbs it took awhile to get out of the load the dyno was putting on the motor.

Like I said I need to get to the dyno sheets. If I told you anything off the top of my head I would be lying.

87silverbullet

iTrader: (11)

The motor is going in a 72 Nova. The weight of the Nova was 3050 with no driver with an iron headed smallblock in it. My buddy decided to redo the whole car body wise and we decided to put a fron clip on the car. It should get the car a whole lot lighter than before. I hope to see times like you posted out of this Nova.

Oldsmobility85

iTrader: (1)

I think the camshaft is probably too big for the amount of compression you are running.

I am running a built bottom end with 6" rod and 11
.1 compression. It has a set of Dr. J's prepped profiler 210's with there spec'd isky hyd roller cam that is 640/640 252/252 on a 108 lsa. Bryce claimes all of them that he has assembled make over 600hp @ 6800rpm.

I built the engine myself and did not dyno it but it has been 6.90's @3400lbs its first trip to the track and pulls clear to 6800+. Ithink you are giving up some power with that compression ratio and large camshaft and its ultimately hurting your dynamic compression ratio.

quick77

If you know anyone that would let you try a different intake,that might be some of the problem, a tall single plane,such as Bronx,or dart sells should help. I have seen that cheap power plus intake pull good numbers on my motor builders dyno, the brodix,dart intake are not cheap, but that's what's been used on our stuff for a long time

quick77

Brodix.....damn cell phone lol!

1997bird

iTrader: (2)

Crane has a very nice off the shelf grind camshaft that should make better power for you IMO, it is part # 118411.

Adv dur 290/306
Dur @.050" 260/268
Lift w/1.5 .670"/.625"
LSA 106

Lunati, Comp Cams, Cam Motion, Bullet Cams, ISKY, Erson Cams, etc all make similar cam profiles like this one mentioned, but I have only used the Crane and Erson lobes. I think you will be happier in the long run with this cam as your TQ will come up and you should 60' much better.

87silverbullet

iTrader: (11)

When we built this motor, our engine builder was telling us to go with a Dart intake but we already had the super Vic from the previous motor and it wasn't that old so we just used that.

One intake that I do have my eye on is the composite intake from AFR. I have been contemplating talking to AFR about this intake to put on this motor. This was the intake that Wilson never came out with. I must have called Wilson 10 times and they told me every time "just a couple of more weeks". As you can see it never made it to market.

Paul Huryk

He didn't go 6" rod to make more power, he went for durability and the ability to rev higher if time went on and he felt it needed more power.

Those AFRs were spec'd at 280cfm or something like that (can't remember exactly) so the engine could have pushed out 575hp easy. They didn't offer anything bigger at the time (no 205 or 215). The motor with the small heads made power at low as 3000rpm and made something like 500lb-ft at 3800 or so.