Chevy guy trying to setup a mopar. Second attempt

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whiskey

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Hello all, I hope that you all will not have to much fun at my expense but, I am a Big Block chevy guy and have been doing this for a long time. I have been asked by a close friend that is a Mopar guy to help him out. Not being familiar with these engines, I have a few questions to ask you experts. The car is a 1970 Cuda. It weighs in at about 3800 lbs. Has a 4 speed transmission and a 3:54 rear gear. It has a 440 6 pack that has been stroked to 493 cid. Bore is 4.35, stroke is 4.150. Compression is 9.75 to 1. The heads are stock 906 heads with stock sized valves. He is, in my opinion severely under cammed. The cam is a Comp cams extreme energy with 477/480 lift, and 224/230 duration @.050. This engine currently makes way more torque than he can put to the ground and lays down way too early. I have suggested that he go with a flat tappet cam in the high 240 to 250 degrees duration. To push the rpm band up to shift at 6200. This will sacrifice some low end torque that is just going up in tire smoke anyways. So I would like to know what you guys think or recommend as far as Camshaft specs, and a roller rocker setup. As I said, I am a chevy guy so I don’t know what kind of lift I can get away with before piston to valve problems. The target is to run 11’s on pump gas. Thank you in advance for any help you can give.
Thx
Bill
 
Ok guys I just heard from the guy. His engine builder is recommending a cam of 230 intake duration and 240 exhaust duration with two degrees more seperation and 480 and 490 lift. He is also recommending a port job that costs $400 that will get him intake flow in the 250 cfm area. This is the builder that built it the first time. I believe that he is once again undercamming this engine, and I think there is a lot more flow that could be had by more porting (He has three stages of porting and is recommending stage one). I do not want this guy to spend the bucks and come home with basically the same engine with wayyyyy too much low end and no high end HP. The engine was peaking about 4500 to 4600 rpm. I think this setup will put peak HP at about 5000. He wants to shift at about 6200 and I feel he will be way past peak HP with this setup. Please let me know what you guys think.
Thanks in advance;
Bill
 
whiskey said:
Ok guys I just heard from the guy. His engine builder is recommending a cam of 230 intake duration and 240 exhaust duration with two degrees more seperation and 480 and 490 lift. He is also recommending a port job that costs $400 that will get him intake flow in the 250 cfm area. This is the builder that built it the first time. I believe that he is once again undercamming this engine, and I think there is a lot more flow that could be had by more porting (He has three stages of porting and is recommending stage one). I do not want this guy to spend the bucks and come home with basically the same engine with wayyyyy too much low end and no high end HP. The engine was peaking about 4500 to 4600 rpm. I think this setup will put peak HP at about 5000. He wants to shift at about 6200 and I feel he will be way past peak HP with this setup. Please let me know what you guys think.
Thanks in advance;
Bill
Click to expand...
yup, i have no clue on MoPars either lol! anyways, he can either retard the cam he has now like 4degrees or so (bad idea), or he can step up to like mopars
.590" solid cam (excellent cam btw). personally, i would go to the .600"+ lift range solid. You can hog out the ports to slow down velocity and increase the rpms and
kill some bottom end for more top end. 250 cfm IMO is not enuff for that cubic inch range.. plus where does that peak occure? .450-.500-.550 lift? not much you can
do to 906's after that .550"lift mark without spending big $$$.
 
Yes, his engine builder is going in the right direction, lord knows why he didn't go this route when the engine was stroked. The cork in the mix is firstly the heads that need to be opened up and then going to a hotter cam with a lift in the .570 lift range would be in order (he's still driving it on the street right). The other alternative is spend a little more money and go with the 440 source http://www.440source.com/ aluminum head if they're back in stock that is. The cam in that 440 right now is basically the factory cam for 440 6 packs.
Personally I'd talk to Hughes Engines http://www.hughesengines.com/ before nailing down the cam and head combo.

I'd also recommend minimum 850 cfm Holley or Demon and a Edelbrock Performer RPM intake.

Terry
 
I Would Check With Hughes Engines, They Know Mopars. 309-745-9558
I Am REAL Happy With Their Reccomendations.
 
He is way undercammed. I'm with you Whiskey. Cam that baby up!

11's are quick and you for surley need to open up them valves for a bit. I'd start @ 240 @ .050 just pondering the idea.

Valve lift is limited by coil bind and the clearance under the retainer that should be looked carefully. A stock head max lift is something I'm not off the bat sure about, but I know it's not enuff for a serious cam like the ones you would install for this project.
 
UltraDynes FC303/436~ 303*(adv) 275*(.050") 192*(.200") .436(lobe lift) .009(lash) is a REALLY good camshaft.
.904 lobes, good street manners, potato idle, not bad vacuum (8"hg at least). if thats too much lift, you can also try:
FC301/391~ 301/275/190/.391/.009 same cam, just less lift. 2* less Adv.Dur.
 
Thanks guys! Well I actually cut and pasted the first post from the original thread. The second post was the update. I also have spoken at greater length with the owner and my feeling is that he wants to run in the 12s and keep it cheaper and more factory/reliable. So I still think he needs to run as much lift as he can get away with. (Any guesses?) And be in the 240 to 250 @.050 range with this engine to get the best balance of low torque and good upper rpm HP. I have to keep reminding myself its a stick.
Thanks guys any more recommendations or opinions welcome.
Bill
 
Bill I agree with you also. It needs way more stick. Really needs more head work too. That is a very large engine and to make any power at 6000 rpm it needs to breath out of something other than a straw which is about what it's like now with stock heads and that cam. Get the head flow numbers up to at least 250 cfm min. and use a 250 @ .050 or larger cam. That'll easily get him in the low 12's ~ high 11's depending on how well it hooks up.
 
Still got the 6 pack? That's good for something like 1100 cfm.. Lose the 906 heads - 440 source has what you need - and they're pretty cheap. Stock dodge heade are done @ .500 lift unless you modify them. An engine that big will soak up ALOT of cam, so I tend to agree with everybody else - more cam and more heads. The .590 solid Mopar cam is a good one and doesn't have a fearsome idle - about 1100-1200 rpm @ idle, and would work really well with the Stealth heads from 440 Source - good for .600 lift and smokes a ported 906 head with no modifications - and only $900 assembled and ready to bolt on.
 
I think the only way to really get the power band up is to get more air thru those heads. If he choses to port them, I would send them to Porter Racing Heads in VT. Dwayne is THE man for iron mopar bb heads. He has several Stock Eliminator record holders as customers, and more than a couple FAST guys. (not cheap, but great heads) Or, replace the heads with RPMs or Stealths. In any case, 250cfm is a minimum IMO, and no aftermarket headcan be trusted. Have them all corrected at the shop before running. If the irons are done, I would run 2.14 intakes, 1.81 exhausts and work the bowls, the guide bosses, and the pinch/entry, as in "stage 2". I have gotten 280cfm on intake, and 187cfm on exhaust, and that will feed it, but it will run out of breath around 6K. The up side is, he won't have to rev it that high.

For cams, keeping the "stock reliable" monicker...

I would run the Crane 680761 hydraulic. It will have to be broken in with inner springs removed, but it's a good big hydraulic that is not as fast a ramp speed as many others, and wil last well on the street. It specs at 324°, .552" lift, 252°@.050 intake, and 334°, .576" lift, 262°@.050 exh. Run the sintered iron rockers, as the springs required are pretty beefy, and aluminum does fatigue faster.
 
first thing would be to can the engine builder. Putting a cam that small in an engine that big!!!! I would go with either the 440 source heads or get a set done by somebody who knows mopar heads. As far as cam, a comp hydraulic around 250 at .050 would work. Maybe the XE295HL.
 
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