My new heads are killing me need help

Okay so I got the suspension in the rear fixed, now all I did was have the heads and intake done by modern, the fastest the cars been is 10.54 last year the car was running 9.70s all day long. Now it’s all messed up, I put the timing at 34 degrees but I haven’t touch the carb .. how far up should I jet it? It’s a dog out of the hole 1.54 60 ft where last year I was running 1.28 - 1.30. So what kinda of jets should I go up too ? The car is really starting to get to me so before I through a forsale sign on it I’d thought I’d ask here for so suggestions thanks John

Look at your plugs.

Just because the heads are better doesn’t automatically mean you jet up. You may be to Rich now or issues with the carb from sitting

Haven’t had a run that made it the hole way ..

That was where I was heading. He thinks he's lean but he very well could be rich. The plugs would give a better idea which way to go.

If you had the engine all apart to have the heads re-worked than a bunch of stuff was touched. You could have a problem most anywhere. Could be a vacuum leak, or valve lash, or firing order is off or a few dozen other things.

I'd start with the basics and go from there. Confirm firing order, look at the plugs, check manifold vacuum while running, run a compression check, etc. Almost anything can go wrong when you pull and engine apart and put it back together. I think I've every mistake in the book and then I find another way to make one.

Checked all the easy thinkings. It’s just not running anywhere near what it should and I just can’t figure it out

What carb and what jets are in it now ?

Can you get or borrow and AFR guage?
Can you get to a chassis dyno to get help in trouble shooting and dialing the car up?
Is it blowing black smoke, a dog at idle/off idle.
Somehow i think you would know if its "that" rich.
Can you get someone to video a burn out and a run ?
What does engine vacuum look like at idle in neutral and i gear?

Are the plugs black and sooty or white as snow?

How long did your fuel sit?
Down here is "really, really" easy to have ones fuel turn to engine puke solution- wont run for squat.
Checked floats/fuel pressure?

Is distributer locked out or on a timing curve- if on a curve, make sure curve is still intact( nothing gave up in distributer)

we recently had an MSD issue, actually the connector between distributer and msd box- i check that all the time now- grin.

Sure hope you can find your gremlin.
How are water temps?
Any pressure in the cooling system after the runs?

I’d see about borrowing a known good carb off a somewhat similar combo.

Some guys laugh at me for never having an engine on a dyno in 44 years but having a RacePak in my car gives me info on every pass, not just in the dyno room.

Which spark box are you using?
The only thing i have ever had go bad that killed a ton of ET was a Digital 6 box. Took half a season to find the problem. Swapped it and car came back.
It would cause a miss in second and third gear was the symptom

agreed John
Dyno's still offer things a racepak cannot but a Racepak ( data gathering) offers us many things a dyno just cannot.
I do like the engine dyno for several reasons- one of course is that if we have any major issues we don't have to pull an engine.
The second for me is the repeatability that allows for testing/experimenting and that it doesn't put wear on the car.
But as soon as i can gather more data- I doubt i will ever use a chassis dyno again.
You have your chassis dyno every time you make a pass and with far more "real world" data than a chassis dyno can give.

If a brand new build car build and it was high hp, I would likely still hit a chassis dyno for a few pulls but, thats about the only reason i can think of if i had a Racepak.

* Jet for MPH.
* Squirters & pump cams for 60'

Be careful so one doesn't overlap the other. (i.e.: too much jet can mask a need for bigger squirters and/or a bigger (longer squirting) pump cam.

Smaller squirters will increase the duration of the squirt and bigger squirters will shorten the duration of a given pump cam. You don't want the squirt any longer or shorter than necessary because it will mess up the A/F ratio of the main metering system (jets).

Yep. All that stuff contributes to optimal ET’s. But his car is off 8 tenths or more.

John I have a good running 1050 Quickfuel I could let you use just to see if it changes at all.
I work in Kent not to far from you.

Gus

Gus I may take you up on that ..
here is a run done on the car

It’s now a 493
-1 ported heads from modern
Ported intake
1050 AED carb 95 primes and 96 second shooters I could tell you
11-1.1 comp
Crank trigger
Msd 6 al
Small roller 316-321 283 and 288 at 50 and .660- 663 4500-7200
Timing is set at 34
Checked wiring and all other small things.
This thing should be running 9.5 or better . Things a beast
In the Pitts and road but track not so much. I’m at a
Lost.

I have a 540 with B1s and a much larger cam then you .
1150 Carb and I have 93s in mine right now .

That’s what I’m getting at .. this thing should fall In the 9s ..
hell my 438 ran a best of 9.98 .. I might just put that back
In ..

I know you can’t compare carb to carb but my old high 9 oldschool (906 heads) build had 99 jets in my 1050 carb. My 8.50 build with 440-1 heads had 90-91’s Jets in the same carb

Any chance the relief is stuck in the fuel pump? I had that happen once and it would never show a symptom until you tried to launch the car at the track.

I'm with you. His problem is not jets and squirters.

How many mph is it off?

I would be looking for something bigger that was touched when in the motor.

Well it’s coming back out. I really didn’t to have to pull it again but it is what it is I guess.

It’s off over 20 mph was running 140 ish and 120 to 124 was the beat

The cam is big duration wise for 11.1 compression. You check cranking compression?

Yeah was all between 170-175 was the highest ..

But again the only change made was the porting of the heads and intake ..

You run pump gas?

No I run 110 race fuel

Have It dynoed........ figure out if it’s the motor combo, an accessory(fuel pump, ign, carb), or something else in the car(converter, wiring, etc).

If the motor makes the expected power, you can rule that out and focus on the other stuff.

I’d bring my carb and ign box with me if you get it tested.

Well I just pulled the motor for the 4th time this season and I can tell you it’s getting old pulling a B.B. out of an a-body. I noticed that the exhaust looks all sooted up. I think I have my carb space on backwards so not sure what that will do. Then I got busted tell on my converter and can’t seem to find anyone to fix it so I Guess I will weld them up and try it all again. I don’t know what else to do ???

Id put the jets back to last year. then check Cam degree!

Done and done ... nothing seems to make a difference

Your sure the mark on the balancer is right?? leak down and compression test maybe it is hitting the valves?
so does it just lie down right off the line? Valves are not marking pistons. no missing just flat??

Everything looks new, it’s got 2 runs on a fresh rebuild .. no idea what’s up. I have a set of stock max wedge heads I was thinking of throughing them on to see if there is a difference..

Sometimes you need a fresh set of eyes on a problem like that. Do you know any engine builders who will take a look at the engine with you? Sounds like you're missing a bunch of power so it has to be something fairly big. It could be the convertor or the trans too. Those things can kill your ET if they go bad. Heck, one time I lost a bunch of power because my emergency brake got partially locked up. Took me a while to figure that one out!

When a car slows down after a parts change their is a reason for that change, figuring out what is causing it can be the hard, challenging part
Reading your other post about the converter I would look very hard at that, those teeth don't break normally
Converters die and get worn out

Maybe I missed it, but have you told us all of the stuff you did check? Might be easier than us guessing what it could be.

Looks like your missing about 200 hp.

First thoughts:
If the car has mufflers, something sh** the bed there
What's your trap fuel pressure?
Cranking cylinder pressure?
Cylinder leak down?
Converter sh** the bed
Fuel line problem between gauge and carb
Cam timing off
Ignition timing way off
lost lobe

I know in the past that I have been so convinced that something was right that I could not see that it was not.

No the converter issues happened long ago and I just kept welding teeth on it but it’s getting to messed up to keep it up.
Checked wiring
Checked timing
Checked comp test 170-175
Checked leak down was not a noticeable difference
Checked cap and rotor
Checked crank trigger
Checked ignition box/ tried my 7al
Trans temp is good. I just don’t know where else to look

This is a good example of why if someone brings me a motor with the intent of me making a few changes to increase the power output....... it gets put on the dyno before being taken apart.

This does two things(for a drag application).....
-establishes a baseline number to work from.
-helps determine if the “car” is running the et’s it should for the power the motor currently makes.

I’ve seen it go both ways before.
-The car was slow, but the motor was doing exactly what it should...... so no changes were made to the motor......... and the customer diligently worked on the car and ultimately picked up over .5 ET without making any more power.
-The car was slow...... and the motor was down a solid 50hp from what I was getting from very similar combos.

Of course, then there’s the situation where someone buys a motor that came with a dyno sheet, and the car hasn’t been running et’s or speeds representative of the dyno numbers are....... and they have spent thousands on fuel system upgrades, trans parts, converters, maybe some gears, etc....... all to no avail.
Then we put it on the dyno and it’s down 50, 75, 100hp from what the dyno sheet that came with the motor shows......... and the car is going exactly as fast as it should, based on our numbers.
It’s this scenario that lead me to start testing before any modifications begin....... to make sure everyone is on the same page right from the start.

The OP’s car is running way way off from what it should.
It shouldn’t be that hard to come up with a realistic horsepower estimate for that combination of parts.
If the motor makes within +/- 30hp of that figure....... you can leave the motor combo alone........ it’s not your problem.
On the other hand, if it’s down 100hp....... better get it apart and start looking.

Obviously, you’d like to test at a dyno service that has a good history of cars running times/speeds that are in line with what’s expected based on the dyno numbers.

How much for the before and after dyno jobs.

Depends on what it is(how involved the installation is), but the least you’d pay nowadays here is $550 per session.

Keep in mind, most of the time when it comes to this, the owner as already spent a pile of money and numerous wasted trips to the track trying to get the cars performance to improve.
The system they’ve been using to make decisions on how or what to try next hasn’t been working for them....... so they’re looking for a different approach.

It’s no different than someone bringing you some ported heads and asking if you can make them any better.
You’d flow them before you started working on them, right?

Absolutely but I didn’t charge for flowbench testing unless it was someone walking in off the street. Then it was 50.00 but then again maybe this is why I totally gave up doing work for others. Lol
I kinda figured 400-500 for a dyno session

A lot of the time when a cars performance is off, the first thing that gets blamed is the motor for not making enough power.
It’s usually when it’s not a “known good” combo, and/or has never been on the dyno.
In that situation you don’t really know what it “should” run.
If you have a bunch of 700hp parts, and your motor makes 700hp...... you’re doing okay.

One thing to keep in mind is, many combos don’t have another “easy” or cost effective 50hp in them.
The pre-disassembly dyno test can save them a bunch of money if the motor combo is already nearly maxed out.
Going from that 700hp to 750hp might require new heads, more cubes, a better block, etc.

Sometimes that next 25-50hp is way beyond what their budget is....... and what money they can spend would often be better spent on other areas, if the car isn’t running numbers that equate to what the motor is making for power.

In a situation like where the OP is at now, dyno testing the motor is part of the diagnostic process.
Just like when your “check engine” light in the dash comes on.
You can hook the scan tool up to it............. or start swapping out parts hoping the light will go out.

Checking that the cam is installed properly is easy and can be done in the car. I had one where everything was installed correctly but was way off from where it should have been.

Why have you not made a full pass?

is that a vague way of asking if his throttle cable is working properly?

Could my msd box going bad cause bad performance. I think it just took a crap on me today ..

Sure can. It will throw you a curve ball for sure. Most people think the ignition either works or it doesn't. I've found that isn't correct. Even with a mag.

Hopefully that's all it is, then you can get it all back together and make some passes.

John have you tried Quickdraw converters? Lots of guys use them. I can also hook you up with a friend that works at Perfect converter company, several fast local guys use them. The guy lives around the block from me(Bubba).1-440-232-9677

I was going to ask how the battery and charging system are....

Read my post way earlier in this thread

I suppose....... but, you said:

Yeah that was my bad . I never took it to that track with the 7 hit just started it and ran it up the road. The 6 was fine and now all the sudden I ha e nothing

I have a perfect 9"converter behind the HEMI - looks good and works great - I asked for 5400 stahl and exactly what I got - price was really good also

That's good to hear DoubleD, Bubba is a good guy I'll be getting my next converter from Perfect.

Pulled another msd 6 al out of my street car and now it won’t start and I did the test like msd says and it works . So I checked the old box and got the same . Now the car won’t even fire .. I’m pulling my hair out with this car this year ...🤔🤔

I seem to be having trouble keeping up with what’s going on......

You’re trying to get it to fire........ but you said:


The right way to test the box is with an MSD ignition tester.

Prob. the dist pick up .
If it's MSD I had one go out on mine .

fwiw- I think I mentioned we have been having problems with Msd units- its been the connector between the distributer to the box.
Maybe a bad run of connectors- who knows.

Indications; Power drop, running rich, then missing, then just fine, then missing, then rich.
Apparently it causes some type of signal jiggle the msd box doesn't like- at all.

I thought i had mentioned you might want to check that but it may have been some other thread.

If you use an msd checker only you can miss the problem if the connection is solid when you are checking.
Check that little connecter- wiggle it a little with engine at 2000rpm.
If thats the problem, you WILL hear it and feel it.
Msd box may be warmer as well.
Whatever that flakey connection issue does to the MSD 6AL, 6 AL2, 7- It doesn't like it one bit.
fyi

The box was bad . Changed it out and all is right with the World 🌎.... seems to have pick up a bunch of power of course that’s set of the pants feeling .. we shall see thanks for all the replies it really helped ...👍🏻

I am confused too! Is the motor in the car or out? Why did you not make a full pass?

You have lost so much power, and right on the launch. That says it must be the ignition some how. Ther would be enuogh fuel in the bowls to carry you almost to the 60 ft clocks. Bad coil? Trigger wire picking up signal from another wire, poor conection, hopefully you do NOT have ignition wired any where through stock wiring. Coil wire have a break or bad connection?

Was out put it back in. I put zippers on it so it’s easier 😂

Was the msd box ..

When you get a full good pass, then you will have absolute proof all is well. Like RedGreen says, we're pullin for ya😀😀

Well just took it up the road and it feels like a beast. It never felt that way on the street so I’m hoping I’m going in the right direction. Thanks for all the input ...

Good luck John

Did you run it out in high gear? If not maybe you should before going to the track

Yes ran it as far as the RPM would let me lol, and it was pulling harder than I can even imagine. So I’m hopeful we will be moving in the right direction

Oh also I forgot I was using a g-tech for speed 1/4 mile, so the results where pretty good just let it roll out then hitting it hard .

Glad you found the problem, post the results

Okay so went to the track today and it ran the same as before . I’m really getting tired of trying things and nothing working .. I’m down some serious power .. I don’t know what else to look at ..

Same as before 10.50's or same as before 9.70's? I thought that your G tech showed marked improvement. What changed since your street run the other day?

Nothing changed I don’t put a lot of stick in the g-meters . Zone run there where over 500 cars . I was not waiting for another run for 2 hours . It went 10.55 st 136 ? I just don’t get it . It comes out kinda flat and then really starts to come on. I went from a best 60ft of 1.28 to today a 1.75 ... I don’t know what to do at this point ..

Look at the converter. Something is eating power.

I'd pull the engine and get it on the dyno to rule that out.

136 mph? That's fast enough for a 9.70 pass. Something is wrong on the launch. The top end charge seems to be real strong. Carb, ignition, cam centerline?

It looks like converter time to me Have it checked now before pulling all your hair out

Check battery voltage/ charging system

Cab I just use that expression I have no hair already !!

time to go with a converter more compatable with your new combo, it may be only port work but it changed the characteristics of the motor and and the power range is in a higher rpm range.

283@.050, not a ton of compression, big heads, big intake....... I’d be looking for at least 5600 flash stall.

Put that thing on a dyno.. hopefully you can
find out what the engine problem is and get a
torque number for a converter.. right now it
sounds like your lost.. spend a bit now and
save yourself a pile later

I would love to put it on a dyno but it’s just not in the cards as I’m semi retired and still waiting on my cash flow to start . I believe I’m have a couple issues with it. One I didn’t jet it up at all after the head work, that’s fixed now. Second is the converter but it get work as I speak and I have an old J in there now, and third I think I’m at the power level that the shocks are going to need to be looked at .. I’m still running the 9000s that came with the kit ..

I have a J conv in both of my cars.. the race
car is basically a stock J that stalls at 5600
rpm in my SB and the other is a J that I had
the stall dropped down to 4700 and the efficiency
is tightened up so it doesnt slip like stock..
that on is in my Rampage... both are 8"

Here’s a video going down the road .. the car was just spinning but none the less

https://youtu.be/ZL_aqLkF-N0