Well let's start with the specs:

406ci
Hydraulic roller cam 230/236 .510/.520 112LSA
AFR 195 heads
10.5 compression
RPM Air-gap manifold
750 Edelbrock carb vacuum secondaries
1 5/8 shorty headers with 2.5 inch Y-pipe very restrcitive exhaust.

Alright its in my 83 Camaro w /T-56 Stage 3 Kevlar STAR clutch and 3.42's out back.

ON street tires it ran 13.5 @ 109 on a 2.4 60' time

Then I dynoed it yesterday:

320 hp and 380 torque at the wheels.

I was expecting more. I wanted to get this baseline then do these mods and see what I gained:
Victor Jr. Single plane port matched to 1205 gasket.
Hooker LT's with true dual dumps in front of rear tires.
and posibly a bigger carb.

How Much could I expect from those things? MY exhaust is very restrictive after the 2.5 inch Y-pipe it goes into a single piece of 2.5 where the cat should be then goes up to 3" I think that may be hurting me significantly. DOes anyone think I need a bigger cam? thanks I just to someone I can talk to that knows engines and can bounce ideas off me.

 

Hey man I was right next to your car when you dynoed.. pretty impressive numbers, its definitely a sleeper!!

I think your cam is matched up pretty good with those heads, and your carb sounds like its the right size. So if i were you.. I would start off with the exhaust like you said. Get some long tubes with a larger diameter cat back and I think you'll notice some gains.

Maybe get a cutout It would sound pretty mean, later

 

Thanks Tunedport341

I can live with the torque number but I wanted more hp out of it. I just read somewhere that no matter where or how long a restriction is in an exhaust the motor will see the whole exhaust as the size of the restriction. So does that mean my motor is looking at my exhaust as a single 2.5 exhaust? Because of that single piece of 2.5 right before the 3 inch? I got to do the dual exhaust and see what I get out of it.

 

O.k. yeah you are right that combo should make more power.

First you have to uncork that exhaust. I'm not a fan of shorties but I really don't think that's the problem. The 2.5" stuff all could be moved up to 3", but the part were you have 2.5" y-ing into 2.5" is a problem. 3"-3.5" all the way back. Then mufflers. What mufflers are you running?

Your ideas are good. Just don't change cams. You do what to add 1.6:1 rocker arms because that is not enough lift for a 406 period.

Change the headers to a 1 3/4 inch setup. If they have 3" collectors even better! Then make a 3" Y-pipe and run 3.5" back from that. Or you can run the duals jut put an X-pipe in there. Are you running mufflers?

Intake, the Air Gap is a good intake. If you are going to a single plane go to a Super Vic. The Rpm rating on intakes is partly B.S. If you are going to rev this thing up to 6500rpm then you'll be fine. A Super Vic on a 406 is about the right size. When you match the ports DO NOT GASKET MATCH! You need to match the intake manifold to the cylinder head ports not the other way around. The Super Vic is a much better design. If you have room for it and a 1" spacer you will do very well.

Carb, keep the vaccum, but just go up to a 850. You can over carb alot with the vaccum and it will never hurt.

I have a 400 package that will do 600+hp and 550 ft lbs (at the flywheel) and alot of my suggestions are based off of that.

Bret

 

I was thinking about doing a set-up like this:
http://www.thirdgen.org/techbb2/show...hreadid=126944

ITs a dual 2.5. I would turn mine towards the rear tires. It seems pretty cheap to do. A custom 3" Y-pipe and a mufflex 3.5 catback would be too much cash. I want to modify the 95 as well

 

Yeah, that motor should put down at least 380 rwhp. Going to the 1-3/4 headers and a 1-inch spacer (if you have the hood clearance) should pick you up another 10-15 hp from where you're at now.
I wouldn't even bother with a dual plane on a 450hp small-block. Chunk it and use the Vic. I don't see the carb being your problem either... personally I'd run a Holley 3310 (750cfm vac-sec), just because I'd rather tune a Holley. No biggie, the Edelbrock's a good carb too.

The rest of your power is, in my opinion, lost to the tuning. How much total advance are you running. Have you tried jet changes??
There some more power there loking for a way out.

-Mindgame

 

I wouldnt exactly call this advanced tech - BUT I will let the mods decide on that one

Anyhow - those numbers seem to be right on from what I have seen from Gen I SBC's.

I would be happy with your numbers - and add more goodies to add more HP

 

Where else would I put this in the 3rd gen forum? I wouldn't get any answers. ARe GEN 1 engines less powerful or something?

 

Why such a little cam for a 406??

-Chris

 

Exhuast? Check this out its just as good as the one that someone posted in this tread and will be good for all around power over the h-pipe
http://www.ls1tech.com/ubb/cgi-bin/u...24;t=004024;p=

 

depending on your plans of the cars- street driving, racing, etc. etc..............I am ASSUMING this is an all stock- heavy car. If so and you have 3.73-3.42 or higher ratio and a mild converter I would leave the intake and try to work with that cam. If you were building the engine again I would use a dif. (larger) one but since it is in there I would use it. With everything else ya have I do not think you are limited by the cam specs just yet. If piston to valve clearance allows I would use 1.6 rockers. I would use larger LT headers if possible, get a better exhaust system and muffler. Those are the major changes to make with out going into the motor a little more. Carb tuning and playing with timing could get ya a little more if that is off. The E.T.s would be MUCH better with
a 1.8 sixty foot.
Alot of people buy 10 to 1 pistons and do not know their comp. ratio. These comp ratios are calculated with a certain thickness head gasket, deck heighth and chamber volume. If the pistons were flycut that loses some also. The only way to know would be to measure and cc YOUR parts. FWI aluminum heads can take/need more compression than iron heads. Also an important thing would be the quench, ya want the piston as close to the quench pad as posible without hitting. (.035-.045 clearance). If your engine builder didn't check the comp ratio by measuring and cc ing or if he Quench is way off then that is some of the problem. If you tear back into it have the block zero decked, use a .039-.041 head gasket, and mill the heads AFTER this to get your desired compression. If ya arenot gonna pull the bottom end you could use a thinner head gasket to get the quench correct and/or mill the heads to get more compression.
Hope this helps

NightTrain66

 

That exhaust looks awesome and I would definately do it but it won't clear the frame on a 3rd gen. The frame on a 3rd gen flares in towards the tranny rather than a 4th gen that goes away. So it wouldn't clear.

 

One more thing. That Exh setup you had a link to will work. Put a X - pipe in it and DO NOT USE FLOWMASTERS! They sound neat but in all honesty the power that they rod is unreal. I've talked with guys who have directly swaped out Flowmasters to Dynomax mufflers on a Engine Dyno and picked up 20hp right there. I use Dynomax mufflers on everything that I can, or something really nice like Corsa stuff on Vette's and F-bodies.


Bret

 

WEll I was looking at SPintechs website. I am looking at two options.

1. Dual 3" oval tubing w/ no crossover.

2. Dual 2.5 w/ X-pipe.

Spintech mufflers are only 2.25 " thick!

 

How about adding a h-pipe or x-pipe to that 3". That's the best way to go.

Bret