440ci Magnum Build

[Carlwalski]

Bump:



Anyone with any more camshaft input? Thus far it's the 284/528 cam (link below).
Anyone think that's fine or have any other suggestions?


http://www.jegs.com/i/Mopar-Performance/312/P4120659/10002/-1?parentProductId=746961




Thanks! 

[Strawdawg]

I would prefer something a bit shorter than that....I have a feeling you will find low vacuum and a need for fairly stiff gears and close to 11-1 compression tho I may be wrong

I personally would go with the Lunati suggested by Neil and no more than the comp suggested by Moper

I see you have pretty good gears...not sure what your compression is...need to read the thread again and see if you stated it

[Carlwalski]

I would prefer something a bit shorter than that....I have a feeling you will find low vacuum and a need for fairly stiff gears and close to 11-1 compression tho I may be wrong

I personally would go with the Lunati suggested by Neil and no more than the comp suggested by Moper

I see you have pretty good gears...not sure what your compression is...need to read the thread again and see if you stated it

Not sure on the compression is sorry mate, probably something lame like 8.4 LOL.



 

[Carlwalski]

For what you have,  I'd go like this:

Comp XE274H cam, lifters, matching springs
Heads will need to be cut for dual springs and small valve seals. If they are off and apart have the bowls blended and the intake gasket matched. Nothing more than that (about what the templates do...).
Edelbrock RPM intake
Holley Street Avenger 670 Vaccum Secondary

Leave the rest as is. IMO, without knowing the details and quality of your existing build, going more aggressive simply doesn't make sense to me. The above stuff will get you a pretty simple and realistic 425-440hp depending on what you already have.

This does sound good looking at the cam specs (1,600rpm-6,000rpm). What else would I need to install this into my engine? I'd like to buy EVERYTHING so when it gets here its all ready to go, nothing missing or needed. I'd also like to stick with the ProForm 850 and Holley Dominator intake (not your suggestions on that side of things). One thing I note is this camshaft is 1 bolt, not 3? On my mild/moderate build, does it really matter?

What are the factory cams, 1 or 3 Bolt? It says "2,200rpm stall" is this a must or simply their recommendation to get the "best" of of their camshaft? From the service manual, my TF727 converter is 2,500-2,800rpm for a 70 440+4 HP. 300rpm off, surely this will be fine? Last but not least, what kind of compression do you think I'll be at with this cam, valve job, port matched intake and 446ci engine? Also, for the record, I have power brakes, soon to be discs on all 4s.


Complete Kit

Shafts, Spacers & Rockers Assembled (Is this needed or can I use Stock Rockers etc with this cam?)




Thanks!

[Chryco Psycho]

Factory cams are 1 bolt buyt you can order any Lunati cam on a 3 bolt blank

[Carlwalski]

Thanks Chryco, do Lunati have anything similar to the Compcam above in a kit?
Any part #'s or links to said kits?


Cheers

[Carlwalski]

2 things I guess 1, I wouldn't know exactly what to order and more importantly, the cam Moper posted (XE274H) is ideally what I'd like (going by the specs) so I would just use that. I'm just not 100% sure if it's a "bolt" for my application. That kit comes with everything, good price too ($460), just needing some confirmation I guess.

[The Cuda Guy]

Based on past testimony here, the rule has always been to use the 3 bolt cams, after some time the one bolt starts to loosen its self lending to disaster.   

Don

[moper]

The XE series are all single bolt. The three bolt is not needed until you're really getting large in the cams. The bolt doesnt hold the cam... the dowel does. So until you get a high enough spring pressure to shear the 3/16" dowel you don't have any issues with a  single bolt. Bolts loosening are the result of either not torquing them properly, or harmonics in the valvetrain or crank. I don't use loctite, don't use a torque wrench to tighten them, and have never had one loosen. "your results may vary"  The MP .528 is a good cam. It's an old design, but it doesn't misbehave like a cam of it's advertized size. Also, the same single spring with dampner will run fine with the XE274H or the MP .528 solid. I like Comp's quality control better. On the carb... I think something might be missing here. The dry flow ratings of the older Holleys, Edelbrocks, and the new bodies that replace Holleys are about 15% higher than the wet flow ratings of the HP and Avenger Holley series and the Demon lines. That's because in a wet flowed carb, the liquid displaces air going thru the carb. So a 670 wet flowed Avenger when dry flowed would be closer to 770cfm. You were looking for an 800 or 850 dry flowed. I think the 770 dry cfm of the Avenger 670 would be a snappier carb on the street and hold the power level in the rpm ranges you plan to drive in. The SD is a great intake, but again, it's more of an RPM peice and for YOUR situation I think the RPM will be a better fit. Again, all opinions. But at least you know where I'm coming from.

[Strawdawg]

How many pounds of compression do you see when you do a test?  Warm engine, throttle wide open>

I have a feeling you are going to be disappointed if you go as big as you indicate you want if the compression is as low as you guess

[Carlwalski]

The XE series are all single bolt. The three bolt is not needed until you're really getting large in the cams. The bolt doesnt hold the cam... the dowel does. So until you get a high enough spring pressure to shear the 3/16" dowel you don't have any issues with a  single bolt. Bolts loosening are the result of either not torquing them properly, or harmonics in the valvetrain or crank. I don't use loctite, don't use a torque wrench to tighten them, and have never had one loosen. "your results may vary"  The MP .528 is a good cam. It's an old design, but it doesn't misbehave like a cam of it's advertized size. Also, the same single spring with dampner will run fine with the XE274H or the MP .528 solid. I like Comp's quality control better. On the carb... I think something might be missing here. The dry flow ratings of the older Holleys, Edelbrocks, and the new bodies that replace Holleys are about 15% higher than the wet flow ratings of the HP and Avenger Holley series and the Demon lines. That's because in a wet flowed carb, the liquid displaces air going thru the carb. So a 670 wet flowed Avenger when dry flowed would be closer to 770cfm. You were looking for an 800 or 850 dry flowed. I think the 770 dry cfm of the Avenger 670 would be a snappier carb on the street and hold the power level in the rpm ranges you plan to drive in. The SD is a great intake, but again, it's more of an RPM peice and for YOUR situation I think the RPM will be a better fit. Again, all opinions. But at least you know where I'm coming from.

OK, I see, looking at the MP .528 camshaft, I'm not sure if that rpm range is to my tastes/goals, 2,200-6,600rpm. Where as the Compcam is 1,800-6,000rpm. OK, I'd be lying if I said I totally understood you about the cam dry flow business lol but it kind of makes sense. I wonder then if it's worth saving money and using the carb I have, it's been good thus far from what I can tell. It's an Edelbrock Thunder Series AVS 800cfm. Also, is that kit I posted in my last post what I'd need to but, anything else?


Thanks!!

[Carlwalski]

How many pounds of compression do you see when you do a test?  Warm engine, throttle wide open>

I have a feeling you are going to be disappointed if you go as big as you indicate you want if the compression is as low as you guess

To be honest, I don't know and thought you could only tell what compression you have by pulling the heads etc? How can I test what compression it has while the engine is running in the car. That would probably help you guys immensely.

Cheers!

[Strawdawg]

With a compression testing gauge.....proper way would be to warm the engine up a bit, pull all the plugs, block the throttle wide open, screw the gauge into one cylinder at a time, crank the engine over until the gauge has seen about six compression strokes, and read the psi on the gauge.

For this purpose, I think it would be acceptable to warm it up a bit, Pull the coil wire so it cannot start, block the throttle open, and pull one plug and install the gauge...spin it over so it has seen about ten compression strokes and read the gauge.  Pick the easy plug to get too like number one so you don't get burned or go thru the ordeal of getting those couple of hard plugs out if you have headers....

The gauge reading can be used to guess at the actual compression ratio on a healthy engine.  For instance a reading of 150 psi will usually be close to 8-1 CR.  190 psi will be in the vicinity of 9-1.  It is not perfect, but, it serves as an approximation.  Obviously, the duration of the cam affects the cylinder pressure...particularly at low cranking speed...

[moper]

yeah, unfortunately there is very little correlation between pressure readings and static compression ratios. So aside from seeing things are in good shape or not, you cant tell much. It's also hard when things were done by places for you and you were'nt deeply involved. So you really don't know (unless the paperwork states it) what things ended up at.
Carl, I don't mean to confuse. Sometimes we are mislead by published numbers and flow tests designed to sound good and catch your attention. It can be difficult to wade through things. Which was why I was trying to educate so you can make your own choices. You were dead on saying the cam is an issue. My angle is if that is the major issue as you describe, why spend a lot of money to revamp the whole top end? It's like racing a car only in first gear and then rebuilding the engine because it wasn't fast enough. You don't know how good it could be. I think the Thunder series is a great carb. Certainly better than the AFB Performer line. But it will probably need tuning. As will every carb you buy. So why not leave it and see how good it can be? It's a perfect match for your expected rpm and usage. Are you leaving some peak power on the table? Probably. But you give a little there to get low end and response because you're not spending 24/7 at WOT at 5K+(we hope  ). The trick is get the car equipped and matched bumper to bumper to what you do with it for a resonable(to you) price.

[Strawdawg]

my buddies SBC didnt crank to 190 and he had 12 to 1 compression... my chally didnt reach 190 either and it was 11 to 1 ....... camshafts is key for this!

what was the rating in 1970 for a 440... 9.5? you said it numbers engine right...

personally Id get a cam and run it........ then go from there as far as buying a carb and a better converter... just my 

That was the reason I mentioned cam duration.  An advertised cam duration of 275 degs drops the dynamic compression ratio about 1.6 ratios from the computed static ratio.  A 300 deg advertised duration drops the dynamic ratio a hair over 4 pts.....according to the papers by David Vizard.  This is the reason that cam manufacturers often state minimum compression ratios for decent performance with a given cam. 

If he has 150 psi cranking compression with his mild cam and then goes into the 284 range on advertised duration, he is going to get a car with low vacuum, and lousy throttle response along with a higher idle speed.  One can put a loose converter on it, but, it may well still be a dog at moderate throttle.

I guess the proof is in the pudding, tho    Hopefully, I am dead wrong. ...well, maybe just wrong...not dead