Could you verify that the secondaries were fully opening? What about a bigger carb? Maybe a 600 would be better. It would be easy enough to try. I would think that 1 horse power per cubic inch should be attainable. Just my 2 cents worth.

Rick

carburetion is less than 600 CMF? I was using 500 cfm on a kind of stock slant (compared to yours at least is stockish)

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Juan Ignacio Caino

Please use e-mail button istead of PM'ing. I do log in sometimes but I'll be answering quicker thru e-mail.

if you were to ask me the thing is under carbed, i know all the formulas add up to a 420cfm at 6000rpms for a 225cubie but in all my years of racing at the track and with my street car nothing smaller than a 600cfm works for max performance. my street car is 3100lbs runs 14.20 ets with 0.030over bore 318vavles 10.7/1 compression,284/520 lift , 32deg total timing and she loved a 600cfm. my race car 2500lbs runs 12.30ets with 0.060 over bore 360 vavles 11.4/1 comp,290/.540lift, 25degs total timing and she loved a 750cfm. your long stroke and big bore should have at lease 700cfms only my opinion good luck

1. I watched him take a picture of the degree wheel. How can one check the cam timing without removing the front of the engine?
2. Don't know
3. No A/F reading. I also thought is to be wierd but he said he was measuring the BSFC. Which my understand is that this is the amount of fuel being burned per hour and he said he was able to figure the A/F ratio.
4. I really don't think so. If I had to guess it might have been calibrated when it was installed 10-20 years ago.
5 I put the oil in myself and it was at full after the breakin.

We're running, well now its I am running a 470 cfm holley 4 barrel with vac secondarys. We thought about trying a 600 cfm but nobody had one and after we blew out the first clutch disc we where running short on time. As for the secondaries openning fully I don't know, but I did hear them come in. The engine seem to bog a bit when they came in. Now its possiable that the operator increased the load at that point but I really just don't know. I was a bit irritated about the whole thing. Maybe I don't know how it done but I paid to have the motor tested and it sure seemed like I was the labor and brains behind the process. One thing I am sure of is that I am NOT a great tuner. I thought I paid for tuning along with the testing. I brought me buddy with me and he couldn't count the number of times I rolled my eyes at him.
Anyway, the venting is over. I think the only way to know whats going on or really what I have is to go to a chassis dyno.

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67Cuda,FAST EZEFI,340cu,CR=10.25,RollerCam&Rocker (XR268HR,#20-810-9)(#1622-16)(EddyRPM#60779,#7576), (MSD6AL,#6425) A904, GearVendorsOD, 8 1/4,3.55:1, ClassicAir

34 degrees for max readouts makes me think of underachieved compression ratio (or at least calculated by ross perrot ratios... )

do we have PSI readings on the cyls?
470 CFM for a performance aimed /6 with the level of labour you've put into her seems low, like almost BBD low I'd try a 600 for baseline... with your build you're going to need a nice shot for accel pump, large cam long duration .28 - .30 accel pump nozzle.

I wouldn't be delighted with 300 lbs/sq ft torque on that particular build. Not trying to bug you down... but I do think that you need to break in your engine "real-world-break-in" then after being familiar with it going to the dyno. I don't think this reading is accurate, but I do think that your engine builder may be giving you the BS at some point. I would open my eyes too on that spark plug thing... the extended nose NGK's may have rise the CR... I do think your CR is a little off.

I have used this year with the car appart to start building another slant. I found myself a sunnen machine equipped engine shop in my home town, and since I'm on the trouble, I dynoed my "old" slant to see how much bang for the buck I'll get. My slant is built like this:

head: speed ported (by me) I went cold feet. Head could have used a more aggresive porting. new valves hardened seat, 2 mm off. steel gasket. Didn't CC'ed the combustion chambers.
cam: about 290° low lift lumpy idle horrible ramp (hyd lifter ramp)
carb: 2 barrel 500 cfm plus (doctored up)
ex: dual 2" pipes, large tube headers, no intake heat, H balanced
forged crank in STD, pistons in +020, good rings, deck height -2.8 mm
MSD 6AL ignition
NGK iridium plugs (regular nose)
melling oil pump
recurved electronic chrysler distributer, timing specs: 16 initial 30 total (may be 2° advanced or retarded according to my crankiness that day)
best run was 208 hp 258 lbs sq feet torque.

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Juan Ignacio Caino



Please use e-mail button istead of PM'ing. I do log in sometimes but I'll be answering quicker thru e-mail.

well watched the videos. I'm a musician so don't jump on my back for this comments: I think I hear "low" compression. I mean, I've listened to several slant sixes, I'd say hundreds of them, some racing engines, in several displacement/cam/compression/exhaust configurations. I have 20 bux that says your cranking pressure is below 135 psi when hot (as is on that video) Also, I hear that clutch slipping more than 10%. Is that a 9.25 or 10" unit? I think your torque is way more than 300 and that can be hurting dyno's credibility if it's causing clutch slippage. If you had more than 125 PSI crank pressure I'll send that to the board. wanna bet?

I don't like lash specs and I don't like how that cam idles. (could be from the lash but I'll recheck the degreeing) this might be hurting your volumetric efficiency and overall engine performance.

I don't think secondaries are properly dialed in.

just my .02 (and my 20 bucks bet, hehehe )

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Juan Ignacio Caino



Please use e-mail button istead of PM'ing. I do log in sometimes but I'll be answering quicker thru e-mail.

That ignition timing is too high to make best power, unless something else is screwed up. Would be nice to know cam degree setting, as any cam manuf spec is about 4-6 deg more retarded than optimal.

If they are not reading AF ratio with a wideband O2 sensor, they (or you) should set that up. It's about $400 for a complete kit with sensor. You will save soooo much time tuning...

Lou

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Home of Slant6-powered fun machines

Its hard to diagnose a problem this complex over the internet. My personal gut feeling from what I have previously read is you are under carbureted. The last post referring to an A/F ratio sensor would also be my first step. I think you will find that you are running out out of carb right when the horsepower is beginning to build. Did you just bolt on the Holley right out of the box? Any changes made during the dyno runs to the jetting etc?
Did you get these cubes from a cut and weld crankshaft? I suppose the scariest possibility is the rod journals were welded off their original theta centers which might explain a "degreed in" cam shaft with 34 degrees of initial timing. Either way, I would check the carburetion first and move on to the less desirable possibilities.

Best of luck,
AZ

while undercarburetion is a very likely chance, It wouldn't explain the 34 degrees BTDC total (not initial) timing for best readings.

the crankshaft stroking job screwup is a good theory too. (not the best for brennan but good one indeed)

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Juan Ignacio Caino



Please use e-mail button istead of PM'ing. I do log in sometimes but I'll be answering quicker thru e-mail.

It runs... it idles...

nothing fell off....

Many people would love to be where your at.

Toss the thing in your car and make it driveable,,,,,then worry about pissing rights with the dyno numbers. The small carb is perfect to teach your car how to chase its own parts......then step up when everything else is working.

Frankly I would be more worried about clutch and flywheel issues....



Get that thing working so we can meet somewheres I can kick yer ass with a 2 bbl car........

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Yeah....Im the one who destroyed this rare, vintage automobile.....

the more I think about it, the less I like the 34 degrees of timing. Especially since we're talking about a FRESH engine.

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Juan Ignacio Caino



Please use e-mail button istead of PM'ing. I do log in sometimes but I'll be answering quicker thru e-mail.

Put that motor on a real world dyno.....the race track.

Get it in the car and bring it to Valdosta this weekend.

If you have an O2 bung welded into your exhaust, you can use my Innovative LM-1 unit to tune it.

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Slant Cecil

I really don't think you will see a big gain with a bigger carb. I have gone just as fast with a 390 as I have a 600.

Dynos are good for tuning, but dyno numbers don't really mean a whole lot other than bragging rights.

I agree with Cecil. Get it in the car and get it to the track. Timeclocks do not lie. (usually )

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Official Cookie and Mater Tormentor.

This thing should be a monster and I think with a little tuning it will be. I don't mean to pick apart someone elses hard work here, just constructive guessing . I think a good carb and a well tuned carb is going to make a BIG difference.
I agree that since it didn't blow up with all the post engineering done is a really good sign. Are you planning on running an MSD? With that much piston dwell you should see a substantial gain with an MSD ignition box.

Keep us posted. You got everyone thinking on this one.

AZ

Theres no way I'll be making it to Valdosta with my busy A/C season bearing down on me and without trailering this brand new setup I really don't think it would be smart. A few trips around town would be a good starting point.

Sandy, the clutch issues where only a dyno issue. I am running a 904.
We ran the same type of MSD 6AL on the dyno as I have installed in the car.
As for bragging rights, that was not my goal for dyno testing this motor although its nice to talk about big numbers. The reason for testing was to see if I got what I PAID for. I believe I bought a very durable motor that is in need of some serious tuning. I also thought that dynoing it would take care of alot of the tuning. It seems that I was wrong. I guess you get what you pay for even in the testing deptment. ($400 for the day)
"Drive it. It runs. Be happy" as someone said. PLEASE, good money was spent. I'll be happy when its right.
That leads me to what is right? I would think that at least 1 HP per cube is the bear minimum I should settle for. Does this seem out of line?
Let go over what I was looking for before I started this build. This was also discussed with the builder.
First above all, I wanted a realiable durable build. Second, Be able to drive it on the street with only mild driveable issues. Third I was shooting for the mid 14's in the 1/4.
We discussed the Holley 600 but picked the Holley 470cfm because it would be a little better for the street and would likely only give up a little on the top end. To me a little was explained as 10-15HP
The 470 was bolted on and tested as is. 57 primaries 57 secodaries jets. Later we changed the rear jets up to 58's and changed the vacuum secondary spring to a lighter one ("oops wrong way") and then to a heavier one.
Cam timing.
Lets say the cam timing (degreeing) is wrong by 4-5 degrees, can this really kill the power that much? Can I varify the cam timing in the car without removing the timing cover? I did varify the damper timing mark is correct.
Ignition timing.
What typicly is the max total timing that Slants like? As I remember it was around 30 degrees. Is 34 degrees really that much more to cause extreme concern? I also question the timing lights accuarcy. Did you see the old thing in the video.

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67Cuda,FAST EZEFI,340cu,CR=10.25,RollerCam&Rocker (XR268HR,#20-810-9)(#1622-16)(EddyRPM#60779,#7576), (MSD6AL,#6425) A904, GearVendorsOD, 8 1/4,3.55:1, ClassicAir