Dissapointing Results - Have I Missed Something?

[mhjo]

Thanks. Well, the "roller" cam is not stock replacement. I can easyly get headers installed and I can barrow a larger carb for testing.

Will tube headers make a noticible difference in sound compared to the HiPo manifolds? I have a quiet ride and want to keep it that way.

 

[rbohm]

yes tube headers will be louder, by how much depends on the rest of the exhaust system.

 

[candphall]

If your engine runs smoothly and you are happy with the performance I would disregard the dyno numbers. You can spend hundreds of dollars to gain an extra horse or two but at the end of the day it won't make a significant difference in the way a car performs on the street.

 

[mhjo]

Candphall, you may be right, but I will double check anyway. I called the company that did the dyno and we have agreed to the following:

I will install a set of used headers and deliver the car to them. They will test-install a larger Carb (actually an Edelbrock 600) and run the dyno test once again.

This will be done in April, and I will post the results here for everyone to see.

 

[iskwezm]

the first thing you need to do is determine exactly what your current compression ratio is, and work from there. since your engine is already together, you can make a few assumptions that can be corrected later if need be. the first thing you need to find is a good compression ratio calculator on the web, someone here will have a link to one.

the next thing you need to know is the combustion chamber volume. with the edelbrock heads i believe that is 60cc, but check to be sure.

most pistons are down in the bore about .002", chances are the compressed thickness of your head gasket is .053", so when you use the compression ratio calculator, you can plug those numbers in along with all the others required.

i suspect that your compression ratio is going to be around 8.5:1, and you want it to be around 10:1. once you have the compression ratio calculated, you can play with the numbers to figure out how much you need to shave off the head to get to the compression ratio you want.

This is exactly what I went through. I went from stock heads with 54cc chambers to Edelbrocks with 60cc and went from 305 RWHP to about 217RWHP with a Edelbrock RPM cam, Performer intake and 600 carb. Edelbrock claims 367 FWHP with their package and in small print recommends at least 9.5 CR (which I was told there were other changes). But my numbers were almost identical with no other changes other then the heads.

 

[Cool Beans]

I would never have thought. . .but my little bit of engine building experience has been mostly stockers, lol. . .can you put in thinner header gaskets to bump the compression up?

 

[Noobz347]

head*

 

[7991LXnSHO]

Sometimes a thinner head gasket can be used. But you need to see what you have now and what is available. I usually hear about gaskets being used to fine tune compression. You may need a bigger bump than just s gasket change.

A 600cfm carb is good for basic 302's, so I would not go bigger than that on a 289. With an auto tranny, are you running a vac secondary carb? If it is a Holley, see what spring is used, otherwise, see if the air horn flap is set too tight etc. Just make sure it is opening the whole way under full throttle and load.
Your static timing may be fine, but what about the curve and total advance? A "pro" recurved my Olds HEI like he would a Chevy, and it ran like a three legged dog. It sounded fine but lacked beans. I put the right springs and weights in and it went back to being a fun car with a boatload of torque. Also, some early Stangs have a dual port distributor vac advance/retard. If the hoses are hooked up to the wrong port, it could retard timing under full throttle and suck power. It has been too long for me to be sure which line goes to ported vac and which to manifold vac.

I do not think headers will be a big noisemaker with good mufflers. If you use Dronemaster mufflers, even stock manifolds are loud.

 

[barnett468]

If you look on top of the post, I just got the car back from tuning. Timing was of course also checked.

I don’t see an engine size.


If it is a 302 and your pistons are not flat tops you need to mill a lot off of the heads.


If it is a 302 with flat tops you need to machine the heads to 57 cc’s.


You need to measure how far the pistons are down in the bore at tdc. . you need around .040 clearance between the top of the piston and cylinder head . . adjust this clearance with thinner head gaskets from cometic.


Those heads come with either 1.90 or 2.02 valves, which ones are they?


try a 1/2 to 1 inch spacer under the carb.


Buy a 600 cfm quick fuel vacuum secondary slayer carb or an ss style if you have more money . . the comp cam guy is an idiot 500 is too small.


that is also a horrible cam for those heads.


Buy 8, 1.65 or 1.70 rocker arms for the exhaust.


Set your valve train geometry.


Plug your distributor vacuum advance.


set your idle timing to 12.


Set your total timing so it reaches a max of 32 degrees btdc at around 2600 – 2800 rpm.


1 1/2 inch tube shorty headers will be a little better . . hedman elites are good.


you need at least 3.23 gears, 3.40 would be better.


the mustang dynos read lower than most . . another type of dyno would show around 25% more power.

 

[SadbutTrue]

Performer intakes are generally worthless on Fords. Performer RPM or Stealth will out perform it at every RPM (even the low ones).

Not true on an SBC supposedly, but on SBFs skip the Performer line and go straight to the RPM.

 

[65FBE2]

I think you are getting good performance from what you have. That's a very nice street combo. If you want more power given what you have, it's all in the cam. Change that to something bigger and it will wake up nicely. But you will give up some bottom end and drivability. That's a concern with the AOD. Your carb and manifolds are fine and not an issue. You would only need to go bigger on the carb and manifolds if you cam it to pull over 6500 rpm. It's easer to make high HP with high compression but it comes with a price and expensive gas if you go over 10.5 , I have made 471HP from 344 stroke engine with 9.2 compression. Big heads and cam 650 cfm carb. So it can be done. Not a very drivable combo though. But it would hurt somebody on Sunday.

 

[65FBE2]

I don’t see an engine size.


If it is a 302 and your pistons are not flat tops you need to mill a lot off of the heads.


If it is a 302 with flat tops you need to machine the heads to 57 cc’s.


You need to measure how far the pistons are down in the bore at tdc. . you need around .040 clearance between the top of the piston and cylinder head . . adjust this clearance with thinner head gaskets from cometic.


Those heads come with either 1.90 or 2.02 valves, which ones are they?


try a 1/2 to 1 inch spacer under the carb.


Buy a 600 cfm quick fuel vacuum secondary slayer carb or an ss style if you have more money . . the comp cam guy is an idiot 500 is too small.


that is also a horrible cam for those heads.


Buy 8, 1.65 or 1.70 rocker arms for the exhaust.


Set your valve train geometry.


Plug your distributor vacuum advance.


set your idle timing to 12.


Set your total timing so it reaches a max of 32 degrees btdc at around 2600 – 2800 rpm.


1 1/2 inch tube shorty headers will be a little better . . hedman elites are good.


you need at least 3.23 gears, 3.40 would be better.


the mustang dynos read lower than most . . another type of dyno would show around 25% more power.

The carb is fine for that cam. The comp guy was dead on given the cam selection. Now if you go big on the cam and higher on the RPM then the carb is limiting but not by much. The hP exhaust manifolds are every bit as good as shorty headers. I've been there and done that. Buy the bigger carb and add the shorty headers and I garantee you will be disappointed. You will gain nothing.
My 344 running 7000 rpm on the dyno with full on race prepped carbs. We tried it with a 800 cfm the a 750 quick fuel and a 650 mighty demon. The 650 made them most power and trq. The dyno I used could measure Air flow consumption as it was entering the carb and it never went above 600. A 650 carb on a 450 plus hp small block was not a limiting factor. Do you really think he needs to go bigger with this combo?

 

[mhjo]

I have dual 1 1/4 " dual exhaust (Dynomax VT mufflers).

Many different opinions I can see. This is not easy for me.

I am now looking at replacing carburetor, intake and manifolds (Edelb 500 cfm Edelb performer int and K-code manifolds)

The suggestion I have so far from my parts shop is Edelbrock RPM or Weiand intake, Holley Avenger 670 and Tri-Y header.

What would be a Perfect combination when haveing this cam????:

http://www.compcams.com/Company/CC/cam-specs/Details.aspx?csid=815&sb=0

 

[mhjo]

We have found an error. The dealer sold me the wrong cylinger head.
Aluminum Cylinder Heads - Ford - Small-Block - E-Street - Edelbrock, LLC.

It turns out it is not meant to be installed together with roller cam and lifters.

 

[mhjo]

We found out what was wrong. The Edelbrock E-street heads they gave me with the roller cam was not meant for roller cam!

 

[7991LXnSHO]

So what are the differences between the roller cam and flat cam heads. I suspect mainly a different spring, but please enlighten us!

 

[dennis112]

So what are the differences between the roller cam and flat cam heads. I suspect mainly a different spring, but please enlighten us!

That and possibly the matching supporting hardware to install the springs (retainers/locators.) Just as importantly the proper springs must be set to the recommended installed height to match the open and closed pressures as required by the cam's manufacturer.

 

[Noobz347]

We found out what was wrong. The Edelbrock E-street heads they gave me with the roller cam was not meant for roller cam!

So what's next? Are the folks that helped discover the error the same people that you bought these things from?

If so, are they going to make good on the correct set of heads?

 

[candphall]

Well I am glad you got it figured out. I am very interested in hearing how much horsepower you gained once this ordeal is over.

 

[mhjo]

It is specified in the Edelbrock web site that performer heads are not to be used with roller cam. A motor-specialist will attend to the car in the end of the month. He told me the springs must be switched to type CCA-986-16 in the performer heads in order to work with roller cam.
We also will try a larger carb with RPM Air Gap intake and Tri-Y headers. The car will be re-dynoed and the results will be posted here.