I took the vette to have a dyno run and the results are disappointing.
I have a sorry 159 horsepower Im almost ashamed to say I have a vette. With the this current setup: 159 horsepower!!!!!!!!!

Edelbrock 1406 650cfm carb, Performer 2101 intake, 882 (boat anchor) heads, TRW forged flat top pistons, Lunati 278/288 (adv duration) cam, true dual exhaust with stock manifolds, dual high flow cats, h-pipe set up with flowmaster 40 series mufflers, TH 350, stock torque convertor,
355 gears, HEI ignition with hi-performance coil. 159 horsepower!!!!!!

These are the parts I have purchased to wake up this pitiful engine

Mighty Demon 750cfm mech secondary carb Weiand Stealth intake
Performer RPM aluminum heads (64cc), .100 dome hypertectic pistons,
1.6 roller-tip rockers, Lunati Voodoo cam (.525/.546 lift, .284/.292 adv
duration, .241/.249 duration @.50 ), Streetfighter TH 350 trans, 3000-3500 stall speed convertor, Dynomax headers.

I will get rid of those cats (since my vehicle is now emissions exempt and emission inspections have not yet reached this part of VA), Will purchase vacuum reserve canister if the above cam causes any troubles with my brakes, lights. Since I have another engine block I'm thinking about having it machined to make it a 383.

159 horsepower

 

You can put all the expensive crap you want on a crappy motor, what you end up with is, an expensive crappy motor! Either you have a throw away motor, or you have a cluster ****. Seriously, check that motors compression.

 

you posted a lot of specs - but are missing one that may be the most important... AFR. Did the dyno operator check your AFR during a WOT run ?

 

What RPM did you pull max power at? Either those cats are clogged, you have a fuel delivery problem, you're not getting full throttle, or there has to be something off in your tune-up. Did you get a printout of your A/F ratio? What's your timing & advance set up at? Headers would certainly help to free up some ponies too but even w/o them you should be able to wring alot more power from your motor. Don't give up on it til you've had a chance to work out the kinks.

 

Check your throttle linkage. If your using the stock throttle cable bracket with a Edelbrock or Holley your probably barely opening the secondaries .... how do I know.....been there, done that.

First dyno run on my ZZ4 (350 Hp crate motor) had a whopping 196 horses at the tires!! Come to find out that my throttle linkage was all screwed up. So the dyno run wasn't a complete waist of time & money .... it told me something was seriously wrong with my setup. Haven't dynoed the engine since, but I've ran a 13.3 @ 105mph in it during a test & tune day.

 

I'm yanking that motor. I have another bare block in my garage and I'm going to start from scratch.

 

Lose the Flowmaster mufflers too. Bleve it or not, they are restrictive.

Brett

 

That seems low for that combo, but it's not really a surprise.. None of the current components is really high performance...
The stock exhaust manifolds cost you big HP as does the performer intake.. The performer is by far not a performance intake...

 

After I did my first cam/intake swap, I actually LOST hp. It was only 130 rwhp at the dyno. I was very disappointed....until Lars re-jetted the carb, recurved the distributor, set the timing and FIXED THE THROTTLE CABLE.

My distributor was sloppy and needed bushings and re-curving. Throttle wont open the secondaries...bracket was bent. Carb was 2 jets undersized for my application..... I was ready to sell the car.

After Lars fixed these minor (yet important) things, I went from 130 hp to 210 hp.

Point is you need to look at all the minor stuff before you give up on this set up....fine tuning makes a lot of difference. My cam is a lousy HE260H only. You should be getting more power then the 210 I have. Oh and I also have TH400...

Good luck..........AND GET HEADERS...you are chocking the poor motor.

 

U may want to play with that combo u have now until u get it right. It sounds like ur on the learning curve and throwing more money and expensive parts won't help. Timing and mixture are where tuning makes hp but u didn't post ur info on either. Whats ur full advance and where (rpm) does it come in? Did they measure air/fuel at the dyno?
How 'bout installing an A/F meter to adjust the carb first - this would be a big help on any performance mtr - big or small, now or in future. Can u find a local shop with a dist machine to set ur dist advance curve?
Thats a big cam for the stock ram manifolds and headers would help. But i don't think the hi-flow type cats are all that bad for a "mild" 350 if using duals. But maybe just a 3 angle vlv job and pocket porting those "882's" (if possible for <$250) will wake them up. And reinstall with a thin (0.015") steel shim head gasket for a little more compression and a lot more quench.
U have plenty to tweek "as is". Hey tuning is really the least expensive and the most fun part.
Good luck. cardo0

 

Two things I learned when I had my vette on the dyno..

1) I sux at setting the carb and timing. The dyno operator was kind enough to adjust both while on the dyno. This is the best time to adjust the carb because you can literally see what you are doing to the carb via the dyno numbers. He dialed in my carb over about 10 pulls. My timing was also way off...possibly bad balancer but most likely just my crappy skills.

2) My dyno operator suggested on my last pull removing the mechanical fan and clutch. He thought it was robbing me of power. We did and I picked up 15hp and around 12ft-lbs of torque. The next week I installed a single 16" electric fan. Best money I ever spent.

I agree with others. Get what you have dialed in before spending lots of cash. The dyno operator said my car pulled very well considering the near stock engine I have minus vortec heads. He said that earlier in the week he had a guy with a mid 90's Fbody who had just spent well over $1,000 in after market parts. He said the Fbody with fuel injection and expensive aftermarket pulled only a few more hp than me. I ended up with a best of 251 rwhp and 310ft-lbs of torque with a 350ci. That was with a tired bottom half. The only thing I've done to the engine was installed used vortec heads and a performer vortec intake. Still need to change the cam to match the heads and intake as well as a complete bottom end rebuild.

 

my stock 77 l48,126k, absent smog equip, with headers and a 2 into 1 with cat....pulled 142 HP.......i'm still breaking in the new engine so the next dyno run will be later this summer....don't feel bad ,its easy for people to brag about HP its another to actually measure it....i call it the reality check....in fact i have a freind who will not take his car to the dyno because he scared to see what it will say.

 

I think with tuning you still have 30 or 40 hp, but that's it. If you were trying to find 300 rwhp, your going to have to go with option 2.

 

There seems to be something wrong with current state of the engine. Others have given some suggestions as to what may be causing the low numbers.
Since you already have a spare block, I would have it machined to a 383. You will want to wait until the block is done before ordering pistons. It should clean up a 30 over (if virgin) or they may have to bore 60 over. No sense ordering in the wrong pistons. The new ones you have will not work for a 383. i would not recommend domed pistons for a street 383 as the compression will be too high in most cases. I calculated my compression at 11.2 with flat tops. If you go the 383 route, you might as well get new rods. That way you'll be able to build the complete long block while the current engine sits in the car. Unless you get an internally balanced crank, you also need a new damper and flexplate.

 

I'm your friend.

 

It's not the best intake but I make 300 rwhp with it. The hood clearance and vortec head don't give me any other choice with the Quadrajet.

You should be close to 225-250 rwhp with that combo. The throttle linkage, timing curve and carburator jetting as other said should be checked.

Stephan

 

Follow the advice of Les and others first: Get your engine dialed in! I left over 60 horsepower on the bench by not having my linkage setup correctly. I was only getting about 3/4 throttle when floored. Ignition, valve adjustments, fuel, etc. can produce huge gains in power.

The common thread through most dyno runs is that the owner was satisfied with the power and bragged about what a powerhouse the car was. Then the dyno run...

Take solace in that most claimed horsepower is out to lunch!! Your actual 159 horsepower will probably blow the doors of someone else’s 350hp.

Get it tuned correctly and blow the door of someone's 500hp!

It's easy to spend money on parts. Invest a few in tuning first.

Chuck

 

Follow the advice of Les and others first: Get your engine dialed in! I left over 60 horsepower on the bench by not having my linkage setup correctly. I was only getting about 3/4 throttle when floored. Ignition, valve adjustments, fuel, etc. can produce huge gains in power.

The common thread through most dyno runs is that yesterday the owner was satisfied with the power and bragged about what a powerhouse the car was. Then after the dyno run...

Take solace in that most claimed horsepower is out to lunch!! Your actual 159 horsepower will probably blow the doors of someone else’s 350hp.

Get it tuned correctly and blow the door of someone's 500hp!

It's easy to spend money on parts. Invest a few in tuning first.

Chuck

 

make that two friends....