Dyno'ed My 360..it's a pig..what next?

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These might get some work done before I go to Eddy's...only because I know someone local who can do them without me shipping them out. He an old schooler who's been building engines as long as I've been alive.


If you can get your current setup running efficient BEFORE you go with bigger valves and ports I think you will be happier. Once you change the heads you'll be chasing the tune up again. I'm not sure what valves and port work will cost you but if I had to guess you'll be looking at $700-$1000 roughly when your heads are done, close to the same for edelbrock heads. Then roughly $500 for a new carb. Then you'll figure out that your new setup doesn't like the cam and now you're looking at more time and money, after spending $1200-$1500. Take it from someone that doesn't have a lot of time and money, drive it and have fun. I'm willing to bet that if you found 10-20hp in your tune up you'd be thrilled and you wouldn't worry about the other stuff. Just trying to save you some time, money and heartache. Good luck.

P.S. If HP #'s and time slips do mean something to you then scrap my advice above and by all means spend the money.
 
replicaracer43 said:
THIS.... is a big one!
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Not as much as you'd think, I couldn't tell between the a904 and the a500 when I swapped. Although I'm running a 9.5" PTC converter.

Get a wideband dude. Don't dick around. Get your timing curve down as well.
 
ebigga67 said:
I'm not sure what valves and port work will cost you but if I had to guess you'll be looking at $700-$1000 roughly when your heads are done, close to the same for edelbrock heads. Then roughly $500 for a new carb.
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Maybe if you get a set of used assembled edelbrock heads and don't bother having them checked out by a machine shop. And it's possible to get used or cheaper new carbs for $300 or less if you know where to look.

Guys pay attention to the man's posts he already said multiple times "I will get the tuning sorted out first and then look at other upgrades" maybe it's just me but it's incredibly annoying when people tell me to do something I already said I was doing :banghead:
 
These might get some work done before I go to Eddy's
maybe it's just me but it's incredibly annoying when people tell me to do something I already said I was doing

What's annoying to me is time slips and numbers mean absolutely nothing to him and he's looking for performance upgrades, and if he wasn't he wouldn't be talking about buying edelbrock heads or making his bigger. Performance upgrades and HP numbers go hand in hand.

It wasn't a pig until he took it to the dyno.
 
superdart said:
It's at WOT that it feels like it's not doing it's job, but the lean A/F explains some of that.

It'll get tuned, I'll see what I think, and go from there. Chances are just getting it running right "as built" will be sufficient to keep me happy. Unfortunately I do not have the pockets to throw a few grand at this "issue" when absolute numbers and trap times mean nothing to me.
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............
 
PoisonDart74 said:
Not as much as you'd think, I couldn't tell between the a904 and the a500 when I swapped. Although I'm running a 9.5" PTC converter.

Get a wideband dude. Don't dick around. Get your timing curve down as well.
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A518 uses a lot more power up than a a500
 
If you are still considering fixing or changing heads, ask around and find out what heads produce the most torque from 2500 to 4500 rpm for a motor like yours. THAT is where you want to build power (torque) for the street. If you can build max torque in that zone, you can move the torque peak up some to get more hp with a bit bigger cam, if needed. I am not up on smallblock heads, but have heard 308 castings work well?
 
GeorgeH said:
Whatcha hearing? it doesn't sound right that's for sure
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It's not only what I hear, but also what I don't hear, and what I see/don't see.
The missfires are obvious. But I don't hear a rap in the pipe, and I don't hear a power surge.And I don't see the engine straining in the straps or relaxing when he lifts.

I hear several things, the most blatant of which is missfires, quite a few of them, not only at WOT, but also before. Missfires eat power,cuz not only do you lose the power of that cylinder, now the others have to drag it along. And then there's the disruption in the exhaust. The slug of unburned A/F may light up in the pipe, driving the hot expanding gasses in two directions, up and down the pipe.This totally messes up the scavenge cycle for the next event, but worse, can drive exhaust back into the intake during overlap. When the slug gets into the merge it messes up some to several following scavenge cycles for other cylinders.
Next is the rate of engine acceleration. I can not see the graph, but am guessing the hammer fell around mid 3000.
The first thing that happened was the engine stumbled from lack of pumpshot, and it struggled for a bit. Then it sloooowly started building revs.(Which granted could partly be due to hi-way gears) Then it started missing and you can clearly hear it get lean in the pipes.A couple of times it seems like the rate of acceleration actually slows before picking up again. That means the engine had to accelerate the rollers up to speed again.
Finally look at the chassis straining on the straps,not. She's way down on power.
The rate of engine acceleration remains pretty much the same to what sounds like a premature shut-down. So I can't hear the cam in there. Sure it has a bit of lope at lower rpm, but there's no surge at the top.
So, it's not only what I hear, but also what I don't hear.

The first thing I'd look at is the coast-down graph to see how much power is getting sucked up in the rest of the powertrain.I mean maybe the tranny is dragging or the rear is set up too tight, or the brakes are engaged. Or everything is overfilled with fluid, ot the U-joints are seized,lol..
Then next is a cylinder pressure. You need more than 145ish to put some rap in the pipes.You need 160 or more to be "hot". With aluminum heads 200 is doable but a better target IMO is 185.
And the A/F you already know about.
Of course the cylinder pressure and ICA need to be well co-ordinated. And above all, don't change a thing until you know what you got. You can't set a destination until you know your current location.
 
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AJ/FormS said:
It's not only what I hear, but also what I don't hear.
The missfires are obvious. But I don't hear a rap in the pipe, and I don't hear a power surge.

I hear several things, the most blatant of which is missfires, quite a few of them. Missfires eat power,cuz not only do you lose the power of that cylinder, now the others have to drag it along. And then there's the disruption in the exhaust. The slug of unburned A/F may light up in the pipe, driving the hot expanding gasses in two directions.This totally messes up the scavenge cycle for the next event, but worse, can drive exhaust back into the intake during overlap. When the slug gets into the merge it messes up some or several following scavenge cycles for other cylinders. And I believe I can clearly hear several to many missfires.
Next is the rate of engine acceleration. I can not see the graph, but am guessing the hammer fell around 3200.
The first thing that happened was the engine stumbled from lack of pumpshot, and it struggled for a bit. Then it sloooowly started building revs. Then it started missing and you can clearly hear it get lean in the pipes. Look at the chassis straining on the straps,not. She's way down on power.
The first thing I'd look at is the coast down graph to see how much power is getting sucked up in the rest of the powertrain.
Then next is a compression test. You need more than 150ish to put some rap in the pipes.You need 160 or more to be "hot". I'd be surprised to see over 130 in there.
The rate of engine acceleration remains pretty much the same to what sounds like a premature shut-down. So I can't hear the cam in there. Sure it has a bit of lope at idle, but there's no surge at the top.
So, it's not only what I hear, but also what I don't hear.
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I have crappy speakers but did hear the miss. It didn't seem to totally clear up.
 
I found this;
E3N is 270/280/112, and .050s of 215/225, and lifts of 440/465. This is another case of slow street ramps. The 270 makes a bit of a lope in the idle, but the 215 is just there to keep cylinder pressure up, hence the reason we hear no surge in the pipes.

#1) Here is what your combo might look like
Static compression ratio of 8.0:1.
Effective stroke is 2.81 inches.
Your dynamic compression ratio is 6.49:1 .
Your dynamic cranking pressure is 121.41 PSI.
V/P (Volume to Pressure Index) is 104...........................................104VP
The low cylinder pressure points to your low power output.
and the 104VP points to her being a pig

#2) Here is the same engine with a fast rate 215/112 cam, say with lobes of 39 degrees, making it a 254 advertised, and an ICA of 55*
Static compression ratio of 8.0:1.
Effective stroke is 2.99 inches.
Your dynamic compression ratio is 6.85:1 .
Your dynamic cranking pressure is 130.44 PSI.
V/P (Volume to Pressure Index) is 119............................................119VP
See that jump in VP of 14.4%? That's something you will really feel off the line, and the extra 9 psi will be felt everywhere..

#3) Here's an example of the earlier slow cam, but the compression optimized for it and pump gas
Static compression ratio of 10:1.
Effective stroke is 2.81 inches.
Your dynamic compression ratio is 8.06:1 .
Your dynamic cranking pressure is 161.44 PSI.Y
V/P (Volume to Pressure Index) is 139..............................................139VP
Notice the cylinder pressure now! That's a 40psi increase

#4) And finally the second cam, the fast-rate 254 AND optimized compression;both together
Static compression ratio of 9.5:1.
Effective stroke is 2.99 inches.
Your dynamic compression ratio is 8.10:1 .
Your dynamic cranking pressure is 162.48 PSI.
V/P (Volume to Pressure Index) is 149..............................................149VP
Check it out! now you are at 149/104= plus 43% stronger bottom end and midrange pressure over 160psi. Put a tune in that and roast the tires.Remember this is still "just " a 215 @.050 so your not gonna win money. But it would be a mountain of streeter-fun. And you will be able to drop some rear gear and hit the hiway, and pull some incredible mileage out of her.

#5) Of course the bug might bite, for more cam,lol, I mean if you're replacing pistons anyway, then you might like this;
Static compression ratio of 9.8:1.
Effective stroke is 2.86 inches.
Your dynamic compression ratio is 8.03:1 .
Your dynamic cranking pressure is 160.66 PSI.
V/P (Volume to Pressure Index) is 141.............................................141VP
This is with a 270*fast-rate, so about 230 at .050, about 2 sizes bigger than your current cam, so maybe 30 or more horsepower potentially. Notice the very small VP loss of 141/149= Less 5%, compared to the previous model, yet it is still 141/104 = plus 35% better than your current combo; same 270 advertised......

All of these above models were held to a pumpgas friendly maximum Dcr of about 8/1; so we are comparing apples to apples.

#6) If you went to aluminum heads you could pump up the Dcr to 9/1, and same combo as the last one could look like this;
Static compression ratio of 11:1.
Effective stroke is 2.86 inches.
Your dynamic compression ratio is 8.99:1 .
Your dynamic cranking pressure is 185.88 PSI.
V/P (Volume to Pressure Index) is 163............................................... 163VP
Hoooleee 163.... now there's a tire frier.........still with a 270 advertised......
I ran this on 87E10 at 10.9Scr.............................


Ok so what's the point?
The point is this; You can't just slap any old cam into one of these low compression engines and expect miracles.Many times the bottom-end goes away.

Do you need a VP of 163? Answer;no. But it sure is fun! This makes a real tire frier, from stopped to 65mph and beyond. You can put it in second and leave it there for hours.
How about 141? I ran that with my 292/108 and 11.3Scr. I thought it was weak.But most guys with 9.8 teeners running 268 cams are happy and they're running just 125VP. So I guess it's subjective. A stock 360-2bbl VPs around 120, and you might remember what that feels like.....lol. Hyup you read that right; 120. That's 15% better than your current combo with the 104VP. That's what slow-ramp cam can do in a low-C engine.
I'm currently running 153VP, and there's room to drop a lil, but only because of the rest of the combo.
So 140? I think that would be the lower limit for me. 140 blasts thru the gears pretty good with 4.10s in the back, but slows right down with 2.94s. 3.23s would be the lower limit for me, but I have a 3.09 stick, for a 9.89/1 starter-gear. With an auto, you can usually run one rear smaller and let the TC do it's magic. But since you already have 3.55s back there,in an 8.25;just leave them, it will just be funner.
So there's my analyses. More compression,a faster cam, and then the tune.Any carb but for you.....the 625 is fine.
 
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This post was started 2 years ago. The OP's last post on this thread was sept 2 2015 if he hasn't fixed yet he probably isn't going to.
 
He started another thread, he said he installed a fitech fuel injection system and it really woke the car up, he had a horribly poor tuned carb on there.
 
AJ/FormS said:
I don't know whether to love you or hate you,lol.
So do you agree? Or.........
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LOL, I love u man! LOL
I agree with ya for the most part. What you call rap I call thump and it's just not there. That miss though, my first thought was that it was a fuel heavy exhaust pop. Exhaust valve problem.
 
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Yeah, I looked for black smoke after the accelerator pump went down. No smoke,no rap, and no power, hick-ups in the power delivery, no strain on the straps. The one thing I really wanted to see was the spectators backing away from the exhaust stink. That would have been the slam-dunk as to leaness. But I didn't see it.
I call it rap, cuz it's a high frequency edgyness. Remember those old parts look-up machines with the micro-fiche pages? And every other sheet you had to twiddle the focus knob. And when you did, the picture appeared out of the fuzzy background. Well that's how I liken the sound in the tailpipe as it transitions from fat to lean; the sound goes out of focus, the rap gets muted. More so on the rich side. As you go leaner, it gets edgier, and then it's just suddenly gone. Then it begins to misfire. I love to hear that rap!
Anyway, we may never know,lol.
Sure is a nice looking rear-end tho, with sweet sounding muted mufflers, not that I want them, but they sound pretty mellow.
I had a 74 360 once,with a 4 speed. Back in 77 I think. Only had it for a year or two; the beak got to me. It was of course minty, being just 4 years old. I bought it with N50-15s and airshocks on it, and a monster snorkle hood, with a brand new paint job. What's that? How much you ask? I paid 2000 Cnucks for it. IIRC , I sold it for the same price or a bit more.....without the Ns and shocks, which I seem to remember selling for a total of 350. They were on honking heavy Keystone Classics. I loved that TQ moan. I loved it so much, almost every Mope I had after that, got one, even the current ride.; until the 4150 flanged AirGap went on. Everybody knows the AG is the one to have .......right? Hyup. I sure miss the moan. Funny thing is, it never really moaned on my 367.
Ok enough already, sorry OP for meandering... no that's not the word I'm looking for.......
 
AJ/FormS said:
Ok enough already, sorry OP for meandering... no that's not the word I'm looking for.......
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I think he would have said something by now if he was concerned about his thread getting resurrected or hi-jacked lol
 
Heck, I've just been busy this weekend/week.

The FiTech really helped. 241 hp & 297 lb-ft. Not saying it's a power house, but assuming a 20% driveline loss (maybe more, with that A-518) it's a solid 300hp/370lb-ft setup. That blue smoke letting off the throttle is what concerns me now.

Note the factory snorkle hood on the new video....free is good. Needs paint, but it's in better shape than my old hood.

Before:


After:
 
Oh yeah baby
The rap is baaaack.
And now she's straining on the straps, and
Revving up a a bunch faster.

I'm gonna go listen to that a few more times.

Thx for the update

I think I still heard 6 missfires and saw three of them. Boy I sure like the sound of those mufflers now! I cranked my speakers!
 
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