I missed the 230 psi test when I looked at the post the first time. Myself I really doubt that number. I am quite sure it would not have run as well as it did under load on pump gas. It really would need some race fuel under load and if the compression is really that high it should have fallen on it's face from the detonation.

Be careful just the same and do not ignore any detonation or pinging. It easy to convince yourself that it is just a little, but by the time you hear it it is costing power and doing damage. I pounded the rod bearings out of an engine and it was not worth it. I never want to do that again.

If everyone dynoed their engines, the vast majority would think the numbers were too low. It is a reality check on a accurate dyno. The nice torque curve amounts to making more power more of the time. In the end it should be better. Like the turtle and the hare, only faster. The amount of time spent at whatever rpm range while accelerating is what needs to be considered. A rush of power after the other guy crossed the finish ahead of you is too late. I don't know what your car weighs, but if the gearing is right you can calculate your 1/4 mile speed with that info. You can get a good idea of what the car may do. A nice converter will get it off the line quick. If it is as light as I suspect, I would think it should be easy to get it well into low 14's or high 13s. I have found that a "real" low 14 car is usually faster than most of the high 12 cars on the street.

Even if it is a little on the high side you can live with it and enjoy the extra power since it is not a daily driver. Mixing some 93 and race fuel is likely the best option for a fun only car. VP is my favorite brand and you can choose the octane, the normal red is probably fine though. If Av gas is available and the price is right stay at 50% or less with 100/130 av gas, if that gives you enough octane. The proper octane with race gas or race gas/pump gas will make more power than the av gas mix will.

Since you have exhaust heat under the carb and will be using a synthetic, running the engine as cold as reasonable can help with detonation. A 160 thermostat that flows well can help, assuming the radiator and fan can keep the engine close to that temp. It's not my first choice on a daily driver, but would be the right choice for your setup. Keeping the engine clean will not be an issue with Amsoil or Redline oil. The heater should work well enough for Florida too.

I would not be in a hurry to give up that torque curve either. On a street car with an automatic it is really what you want. If the compression turns out to actually be too high, I would give it the octane it needs or bite the bullet and change the compression. A cam change will not fix it. It would help a little at light loads but never be quite right. At full throttle and peak torque it would still need the higher octane. If you are going to make serious changes, fix only what needs to be fixed. If it comes down to it, maybe the valves could be unshrouded a bit more? Pulling the head in the car is not the worst thing to have to do.

I would run it and see what it does. I would also get a second compresson gauge on it to be sure what it is reading.

There has been many engines that have run as high as 13:1 on pump gas. I know its not every engine that can do this & some will say it cant be done. But the fact is, it is being done & done right with no problems.

The pump gas drags ran the Rocket Fuel that was meantioned earlier. These guys where making around 1000hp on pump gas & ran as fast as 8.52 in the 1/4 mile.

If it was me, I would call a Guy I know & tell him what I had & get him to grind a special cam for me. By the dyno sheet you could use a bigger cam & yes the cam & combustion chamber is the secret to running high CR on pump gas. I think it would do wanders for your engine myself.

But first thinks first, verify the CR is reading what you think & run it to see if it is having any problems at all.

Just for the record there is a guy running 13:1 CR with a blower on pump gas. So many things are possible.

The real kicker is, if you can get it to work. It will be a very effeicant engine & should even get great fuel milage. SO put her to the test, & take small steps in tuning & see where it falls. Youu may be surprised. But IMHO, I think in the end, you are going to need a cam.



Jess

Well the motor is in and just brought it back from the exhaust shop. The exhaust guy needs to learn how to weld, bend pipe, well he just shouldn't be installing custom exhaust systems for a living, but that another story.
The test drive.
I was looking for a little more lop at idle but it not bad for an automatic. Under part throttle it sounds pretty good. From 1/3 throttle to full it pings badly. Its defently going to be fun to drive if I get this detonation under control.
The plan.
I have two car shows I am planning to attend in the next two weeks. Back the timing down from 31 to 27-28 and see if the pinging goes away or/and buy 110 octane and mix it with the 93 pump gas. After the shows adjust the valve lash from 20 down to 12. This should help bleed off a little compression (not much) and help it be a little more lopy at idle.
Then off to the chassis dyno for tuning on 93 and bring 5-10 gallons of race fuel with me if it can't be done.
Has anyone changed a cam in a Barracuda while it still in the car. It just might be easier to pull the motor, I have A/C.

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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

sounds like fun tunning times ahead of you. I can brath now that you've checked that it pings like hell on that amount of timing. Tbhis would support my "slipping" theory on the dyno, and explain how come with slipping clutch assy on engine loading your timing would be way too much for real world application and how come your numbers where that "low". Go 28 total 10-12 or even 14 BTDC initial... sounds to me like Eileen is gonna be a heck of a motor once she's purring like a kitten and well broken in.

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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.

Yep, time to weld the slots in the mechanical advance so you can run 15-18* initial and only 25 total.

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Official Cookie and Mater Tormentor.

I was thinking about buying a MSD timing computer for the curve adjustment.
Took it out for a second run this time I dumped in 7 gal of 110 octane to make a full tank. Not sure what my tank capacity is but its likely about 40% race fuel. Still set at 31 degrees total and a little ping on the top end.
FX1 performance computer results.
1/4 mile 18.55 at 80.1 mph
1000 ft 15.73
1/8 12.33 at 62.2mph
330ft 8.33
60 ft 3.18

If I jump on it at the line it stalls. I have to feather it a bit and get it rolling. When the secondaries come in it bogs down for what seems like about 1.5 seconds and then turns your frown upside down.
Drove it around for 20 min. and it ran great. After some highway speeds it likes to stall when slowing down to a stop. The 2-1 shift stalls it out. Turn the key and it fires right back up. It was idleing at about 950 rpm in gear but now its at about 750 rpm. Choke is full open after about 5 min run time. (electric)
Your opinion on the results and drivablity please.

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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

Your choke opening rate for summer is too slow.

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

Don't you have the 450cfm Holley that has mechanical secondaries and no secondary accelerator pump? If so, there's your bog. The only way to cure it is with a long duration pump cam, 50cc pump, hollow sqirt screw and a BIG squirter. This fix is more of a crutch than a cure, it uses excess fuel. The best fix is to ditch the 450 and put either a 390 or a 650 Holley on it, pick mech or vac sec for the streetability you desire.

Make sure it's not lean. That can be a cause of ping.
Why throw $ to MSD, limit the mech adv in your dist to 16* and run 12*-14* initial with the total of 28*-30*. Try a light spring first, if it still pings, go to a heavier one.

With 225HP and a 3400lb car, the MPH should be in the 95MPH range, with a potential ET of 13.6 (13.6 with optimum gear, tire, convertor).

If I knew you needed exh work, I could have hooked you up with some that does quality work at a fair price. He also has a '67 Barracuda notchback that runs low 10s!

When you get it ready for the track, let me and Charlie know, maybe we can meet up at Orl, Gains, or Lakl.

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Slant Cecil

The carb is a 470 cfm with vac secondaries.
I also have the Vac disconnected and plugged.

http://www.holley.com/types/Truck%20Avenger.asp

I was referred to this exhaust guy. Not a good referral. I can fix it. I had him install a flange just behind the transmission so I could remove it. I'll hit it with a flap wheel, reweld some areas, cut a hole behind the Y section and get in there with a die grinder then weld the access hole up. I may just start again.
I will need your exhaust guy. The tail pipe is hitting the axle on speed humps. The guy said he would fix it but I'll just get the same poor quality again. This guy won't throw out a misbent pipe if his life depended on it. He'll put 5 more bends in it to save it. There is at least 11 pieces of pipe all welded together and at vairous angles. The funny part is that it leaks. I am going to have to have a talk with him. I should have never paid him but I did. Sometimes its less agravation to just walk away.

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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

don't know if this is sarcastic or a good recommendation, I have 15-16° BTDC initial and 28 total mech with little to no vac pod. works for me... what can I say... guess that different cars different recipes...

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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.

Can someone break down the time line here and explain to a novic what these numbers really mean.

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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

It means your car is a pig. j/k

Realistically, it is time to start tuning. The bog is probably a lean condition. Front side may be as simple as the pump cam, secondary side may have low float level or need richening up.

Get your timing worked over and limit total to 28* or so. Get as much initial in it as you can stand.

Hate to tell you this, but with your compression and CI that motor will not work up to it's full potential without headers and good exhaust. You really should be able to run in the low 14's/high 13's when you get it tuned though.

This is the frustrating part and also the time you really, really need to be patient. I know you are disappointed right now, but you will be amazed how much the car will pick up just tuning and getting everything right.

Now is also the time that your frustration will get the best of you and cause you to break something if you are not patient.

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Official Cookie and Mater Tormentor.

My first thought was 80.1 mph was good considering the slow start and indication that I am strong on the last half. My 4100 lbs truck does 78 mph at 16.9. I seems to me if I can get off the line and first half better I should really be getting there. The stock motor if I remember correctly did about 18 or 19 at 60-65mph. It was smooth all the way through.
Carb choice:
I need it to be somewhat docile on the street, thats the main reason I went with the 470 and not the big 600+ cfm. Are you saying that I can have it both ways with a bigger carb? I can see how a mech. secondary can fall on its face, but I thought the vac secondary solved this problem. The carb cam you talk about. Is that the little lever that reaches under the front on the carb that moves the moment the throttle is moved? If there was another one on the back side would I have what they call a "double pumper"?
I realize that there is much tuning to do. I just don't want to spend to much time tuning something that doesn't make sence. I plan on buying some dyno time and don't what to spend it tuning the wrong stuff. If a bigger carb and the correct type will yeild big gains, than thats the direction I should go as long as the drivablity is not horriable. If the 470 cfm holley I have is with proper tuning only holding me back a pinch and is drivablity on the street is great then lets keep the one I have.
I trying to explain what I want out of this car and I realize I can't have it all.
Do we have a vote for the perfect carb for a 258ci that isn't a pain around town but isn't a dog too? Must fit on my 4 barrel manifold.

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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

Leave that carb on, at least for the time being. It is easier to tune an engine that has a smaller carb, then one that has too big a carb. The pump cam is the small plastic piece, that mounts on the throttle shaft, and is held on with one screw thru the throttle lever. There are kits that have different cams, to "tune" the pump shot, along with different "shooter". I had a slight bog off the line, with my new car, at Valdosta. Changed the secondary spring, and cured the bog. There is also a kit to allow easy spring changes, and a kit with different springs. After you get the setup you have now, tuned properly, you could try a larger carb, to see if the performance improved, or you wind up with a case of bog city. I have never tried it, but always thought a "spread bore" carb should work well on a modified street/strip slant.

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Charrlie_S
65 Valiant 100 2dr post 170 turbo
66 Valiant Signet 170 nitrous
64 Valiant Signet
64 Valiant 4dr 170
64 Valiant 4dr 225

I think you need a bigger carb, But I would not go buying one yet. You have alot of work to do, and need to find some anwsers before you go spending in that direction. The 470 will do fine anyway if you can get it tuned, and this you should be able to do.

Your MPH is telling a story, MPH is the best indicator of HP out sides of the dyno. You really should be getting mid 90's & maybe even high 90MPH when it is tuned & working. Anyway with only 80 mph it is telling you that your power is low (even with abad start).


First things first. Pinging any at all is a very bad thing. You may think it is only pinging alittle but if you hear it there is a lot. you can have enough ping to totaly kill a engine and not even be able to hear it. And it pinging with race fuel mixed in is a very bad sign.

Anyway you need to get that timing curve worked out right now. Then you need to get the fuel right. These things will kill power.


I dont know what you got going on with the exhaust, but if it is not good enough to flow what that engine needs its going to hold you back alot. And can even add to the pinging problem.


Right off unhock any vacume you have hooked to the dizzy, if there is any & leave it off. Then set that dizzy up, if you cant just pull the timing back untill you can get someone to do it for you. You cant keep letting that engine ping. I know it has been very little driving, but it really can hurt things fast. Get the timing back to around 28 as was meantioned before.

The 470, is it jetable in the rear, or just the front. It really sounds like the engine is very lean. Be sure and check the float levels. And then add some fuel(bigger jets).

I may have misssed it, but what kinda ignition you have. Is it hot enough for this much compression?

IMHO, I think if you can get the tune up right you will have way more power than the dyno showed. But cover all the basics before making big changes.


Jess