Dyno day for my 505 - Results are in AGAIN

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Can't wait to see results - where are you having this done?

Ken

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The engine shop has a set of 2 1/4 headers for the dyno, but I will have 2" in the car.

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Greg - Dwayne didn't say. He actually recommended something a little bigger for max performance, but I talked him down in exchange for some better street manners!

Mopwers - My goals and plans...well its a 72 Challenger all steel full interior street car with 4.10's, 295/65 drag radials, 3" exhaust, and 9 1/2" converter. I'm hoping for upper 10's, but I won't be legal anyhow (no cage). I need to make a decision on that one...As for why I chose solid Flat tappet vs solid roller. Mainly cost.

Al - If this thing makes 700hp I will flip! Thanks for the positive vibes, man.

Deaks - I get 10.5 w/82cc chambers. Pistons are a couple in the hole and gasket is .040

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It's on the dyno and was getting all hooked up

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sweet! thanks for dropping off the spring tool. I hope to see you tomorrow after work for the fun

WEDGIE - Very cool combo you have there. A real stump puller to the max! That thing must idle like a stocker with the mild cam and all those cubes. I like it

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You're gonna love that motor....that's almost dead-on my old 508 combo except I ran a very similar net spec (allowing 10 degrees for lash) 252/258 @.050 Hydraulic roller with dead similar lift and split. Same intake but you're probably packing a bit better head flow above .500 than my old stage V's.

Did Dwayne port the SD intake? There's some power upstairs there, I'm sure Dwayne knows all the tricks, they're about the easiest BB intake to open up and the long stroke likes the short runners and a big carb.

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OK guys. Made a couple pulls tonight and its not even in the ballpark. timing was at 36 and jets were 78 w/pv and 86. Jetted up 2 sizes and lost power. Tried 34 degrees and lost power. Peak hp was at 5700 rpm - 560hp, peak tq at 4900rpm - 559lbft. Checked cranking compression and all cylinders were right at about 160. Loosened lash .005 on cyl 1 as a test and pressure went up to 175. Valve lash was checked and none were out of line. What do you think the problem could be? My engine builder thinks the cam is wrong and the intake is not great. How much could port matching the intake be worth (if it was off by a lot)? Why would it not pull past 5700??

Here are the cam specs:

262/268 @ .050
lobe lift .390/.400
lsa- 112 recommended installed at 108, and is installed at 109
.585/.600 lift

Engine guys, please help!

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I was going to guess 575HP as the cam is very mild with a wide lobe sep of 112. But you asked for a cam with mild street manors and you got it.

But IMO the peak RPM HP is lower then it should be. So you Do have more there untapped as of yet. mike

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I have never been a big fan of the SD manifold myself. But I know Dwayne and other have coaxed some good number sout of them, I just never have been able to. I would be looking there first and foremost. Assuming of course the cam is where it needs to be and is happy where it is.

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Peak hp was at 5700 rpm - 560hp, peak tq at 4900rpm - 559lbft.

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Gonna try an M1 intake and my 2" TTI headers tonight. I'll let you guys know how it goes.

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OK guys. Made a couple pulls tonight and its not even in the ballpark. timing was at 36 and jets were 78 w/pv and 86. Jetted up 2 sizes and lost power. Tried 34 degrees and lost power. Peak hp was at 5700 rpm - 560hp, peak tq at 4900rpm - 559lbft. Checked cranking compression and all cylinders were right at about 160. Loosened lash .005 on cyl 1 as a test and pressure went up to 175. Valve lash was checked and none were out of line. What do you think the problem could be? My engine builder thinks the cam is wrong and the intake is not great. How much could port matching the intake be worth (if it was off by a lot)? Why would it not pull past 5700??

Here are the cam specs:

262/268 @ .050
lobe lift .390/.400
lsa- 112 recommended installed at 108, and is installed at 109
.585/.600 lift

Engine guys, please help!

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Hey guys - Back from the dyno tonight and after lots of wrenching and changes...not much different. I decided not to try the headers tonight, mainly because we just ran out of time. Plus, the TTI header collectors angle inward towards the back of the block and would have required a little lite fab work to make them work on the dyno. Whatever gains there may be will have to be put to the test once its in the car.

Ok, so I decided to advance the cam and also switch intakes from the Holley SD to M1. The intake swap came first and peak numbers were 567hp at 5800 and 565tq at 4800 (vs the SD 560hp at5800 and 559tq at 4900). So, the M1 helped a bit, but not as much as I had hoped for.

Next, we decided to advance the cam. The Cloyes timing set has 3 settings so it went from 109 to 105. Peak numbers after doing that change went to 563hp @5600 and 565tq @ 4900. Timing and jetting were tested with each change and best timing with the advanced cam and M1 was 36, and jetting 78 and 86.

We made quite a few pulls in all and to be honest, I was just done. I'm sure the headers will help, but again, I will just have enjoy their benefits in the car. I will just have to guess what they could've done on the dyno.

All in all, I would be lying if I said I was completely satisfied. Its more like I have just come to terms with the reults. But despite the let down, I'm not going to give up on it. I'm going to get it in the car, and see what she can do at the track, where it counts. Plus, I have no doubt its going to make for a fun street car.

I guess that old Holley SD ain't so bad after all.

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In the long run, Tony, I think you will be glad you built it the way you did...car should be a gas on the street and dependable. You could always try a cam lift with more lift to take full adavantage of the ported heads. Or you might try some 1.6 rockers some day. Cant wait for some real world track time and see what she does!

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similar to this. don't be disappointed. it is making the correct amount of power for the combo

511 buildup

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Thanks guys for the moral support during this difficult time

Somecarguy - I'm running a Mopar Perf distributor. I didn't check timing above 5k, but based on the smooth graph it doesn't appear to have anything going on with timing.

Sixpackgut - I didn't mess with carb spacers with the M1 as it wouldn't fit under my hood anyways. I did run a 1" open on the Holey SD. I'm not sure the Stealth heads are worth anything in MW form. Have you heard anything about that?

BSB67 - My engine guys says his dyno is definitely more consevative than some other dynos...for what thats worth. I assume the numbers ar corrected and also that carb was opening all the way. The engine was already running on the dyno before I arrived for cam break in. I'll check later today just to be sure.

GCH - I did try a 1" open on the Holley SD, but nothing on the M1. I actually only ran the Holley with a 1" spacer, not without. The carb linkage was rubbing the intake without it. Gonna have the grind the intake a bit for clearance when in the car.

I'm almost tempted to flow one of the heads just to see whats going on with them...

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Thanks guys for the moral support during this difficult time

Somecarguy - I'm running a Mopar Perf distributor. I didn't check timing above 5k, but based on the smooth graph it doesn't appear to have anything going on with timing.

Sixpackgut - I didn't mess with carb spacers with the M1 as it wouldn't fit under my hood anyways. I did run a 1" open on the Holey SD. I'm not sure the Stealth heads are worth anything in MW form. Have you heard anything about that?

BSB67 - My engine guys says his dyno is definitely more consevative than some other dynos...for what thats worth. I assume the numbers ar corrected and also that carb was opening all the way. The engine was already running on the dyno before I arrived for cam break in. I'll check later today just to be sure.

GCH - I did try a 1" open on the Holley SD, but nothing on the M1. I actually only ran the Holley with a 1" spacer, not without. The carb linkage was rubbing the intake without it. Gonna have the grind the intake a bit for clearance when in the car.

I'm almost tempted to flow one of the heads just to see whats going on with them...

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IMO, your whole problem is port volume. i'm sure your heads flow around 300 or so but its still a standard port head. it just cant breath. if those heads are like the edelbrocks, raising the port roof as much as you can where the pushrod pinch is, is the only way to increase the volume. add in the 337 intake and you can use a MW style gasket and dont have to mess with a valley tray anymore. i still think you need way more plenum volume if you run a 4150 carb though.

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Thanks guys for the moral support during this difficult time

Somecarguy - I'm running a Mopar Perf distributor. I didn't check timing above 5k, but based on the smooth graph it doesn't appear to have anything going on with timing.

Sixpackgut - I didn't mess with carb spacers with the M1 as it wouldn't fit under my hood anyways. I did run a 1" open on the Holey SD. I'm not sure the Stealth heads are worth anything in MW form. Have you heard anything about that?

BSB67 - My engine guys says his dyno is definitely more consevative than some other dynos...for what thats worth. I assume the numbers ar corrected and also that carb was opening all the way. The engine was already running on the dyno before I arrived for cam break in. I'll check later today just to be sure.

GCH - I did try a 1" open on the Holley SD, but nothing on the M1. I actually only ran the Holley with a 1" spacer, not without. The carb linkage was rubbing the intake without it. Gonna have the grind the intake a bit for clearance when in the car.

I'm almost tempted to flow one of the heads just to see whats going on with them...

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IMO, your whole problem is port volume. i'm sure your heads flow around 300 or so but its still a standard port head. it just cant breath. if those heads are like the edelbrocks, raising the port roof as much as you can where the pushrod pinch is, is the only way to increase the volume. add in the 337 intake and you can use a MW style gasket and dont have to mess with a valley tray anymore. i still think you need way more plenum volume if you run a 4150 carb though.

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Do you think a better head design like the Indy EZ would have the same problem (also flowing 300+ cfm)? Thats interesting that port volume would have such an impact on a big motor..but it does seem to make sense. I know on my 540 i made 750 ft lbs w/B1 heads, so i think you have something there

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What does the chamber measure? They are usually 85-86 OOTB, and with cnc work, they will be larger. So did you have them milled any?
By your specs, assuming an 86cc chamber you have 10:1. Coupled with the large cam duration, you have no cylinder pressure. That will no doubt take some power away from that engine.
If you read my first post, and check out the build I did in the link, you'll see we used a cam with only 236@ .050 to achieve 535HP and 620TQ!

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I did see your link and combos like your are exactly why I feel my numbers are down. The heads were resursaced by Modern to bring the chambers down to 82cc. My engine builder cc'd a couple just to confirm, and they were 81 and 82cc.

Dram - I don't have a scanner but I'll try to type in the hp and tq numbers by rpm. The only other relevant numbers I have on my printouts are man vac by rpm. Would it help to see those too? I think he said it was a DTS dyno.

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Tony,

Maybe you can take a good picture of the dyno sheet then upload the picture here. That's what I used to do in the old days.

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similar to this. don't be disappointed. it is making the correct amount of power for the combo

511 buildup

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Very cool Defbob. What kind of power did it make? I missed that part. Thanks!

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I figure about 585hp. the car in racing weight (with me) weighed 3805lbs. the car went 11.61 @ 116.9 and then 11.54 @ 116.3 only an hour apart.

video is in the sig.

btw, the car has 3.55 gears