cam input for a 434

[totalchaos]

would like some input for a 434 sbc that i'm putting together. it will have nitrous.
motor specs: motown block
scat crank & rods
je flat tops 12.1 comp
dart pro 1 227 cnc heads
dart 4500 flange intake
1050 dom.
comp cams 1.6 rockers
car specs: 3400lbs
3.90 gaers
th 400
i'm thinking about lunati grind me one of their ra1 .390 lobe profiles, the cam specs: 289 intake advertised duration
297 exhaust advertised duration
.624 lift intake
.624 lift exhaust
109 lsa
256 @ .050 intake
264 @ .050 exhaust
ivo 38.5 ivc 70.5 seat to seat
evo 81.1 evc 35.9 seat to seat
according to desktop dyno this procude about 630hp at 6500 and 580trq at 5000.
wanting your input or ideas thanks.

[Jay Allen]

Here are the important things as I see it.

434 sbc
will have nitrous.
je flat tops 12.1 comp
dart pro 1 227 cnc heads
dart 4500 flange intake
1050 dom.
comp cams 1.6 rockers
car specs: 3400lbs
3.90 gaers
th 400
wanting your input or ideas thanks.
This is going to be a small base circle camshaft. This is a big block Chevy disguised as a small block Chevy. The NOS is going to make the volume even more limited. The camshaft must compensate for that. These are things that we see as racers and simply cannot be duplicated on desk top dynos. Those programs that are wrote with simple language are worthless IMHO.

Here are your cam specs again:
ra1 .390 lobe profiles
.624 lift intake
.624 lift exhaust
109 lsa
256 @ .050 intake
264 @ .050 exhaust

If you had an engine as you described, it was only say 10.5:1 to 11:1, NO NOS and it was a street/strip car, then you are on the right track. Not exactly but you are in the ballpark. If you called Lunati or Comp, it is this kind of response you'd get. It certainly isn't right but it'll get'cha running.

But with NOS and 12:1 compression? To me, that isn't even close. That, isn't in the ballpark. You need more duration. WAY more split. More lift (NO lift alone does not kill springs!) and W-A-Y different IC & EC meaning a vastly different LSA. Read the sticky I put up about LSA/IC/EC.

Please visit my site. You can get there by clicking on the link in my signature. I have (3) build sheets on my site. I have a sheet for all needs. You should complete a *Pro* sheet but you may not have all of that information. If not, then a *std* sheet is you. This will allow me to evaluate all of your stuff and not just 1/10 of what I really need. Do this if you want a camshaft from CI. If not, I 100% understand and I wish you luck!

[Ed-vancedEngines]

Well Jay,
Once again I am agreeing with you.

In an engine using N2o I feel that you need to get the exhaust valve open sooner to help prevent detonation from excess cylinder heat and also to position the lobes for a good clean blow down during overlap.

Even though this is not cam related, I will also suggest to increase the piston to head distance (Quench) in a N2o or supercharged or turbo engine. The idea is to try to slow down the flame instead of trying to spedd it up like you would with all motor and no juice or forced induction.

The heads you have should want more lift too.
Ed

[Jay Allen]

Well Jay,
Once again I am agreeing with you.
Even though you and I have philosophical business differences, both of us know engines. I am glad that we can agree on some stuff.

I hope all is well with you sir.

[Ed-vancedEngines]

Well, I'll be!

Thank you sir.
I have already forgiven you the same day we had our disagreement. That is the way that I try to live my daily lifew is to try to always forgive anyone who offends me or does anything against me. I get more peace like that, plus the bible tells us to forgive and to not let the sun go down on our wrath in a different scripture. That is if you are a believer.

I do sincerely ask you for your forgiveness as well for the attitude and manner in whick I talked with you.

That said;
I do know some of the basics of engines and of suspensions. I do try to help people when I can. That is me it is the way that I am.

I did not make the connection of who you are until I checked a little bit. I did talk with you on the phone a couple of times when you were working with John at Canfield. You never did get me any cut-away pics of the 190 head for me to look at though. lol. :) That is ok, I finally did muddle through it with out doing any serious damage, almost. I managed to break through into the pushrod pinch area a tiny bit, but did get that welded back up. At least I didn't strike water.

Have a good day and a good life sir. Be blessed in Jesus name.

I mean these words in sincerity. I wish to not offend if you are not a believer.
Ed Wilson

[Jay Allen]

I do sincerely ask you for your forgiveness as well for the attitude and manner in whick I talked with you. I had forgotten about it as well. This is why when you brought me up over at Speedtalk I never lit into you. It just wasn't worth it.

I never doubted you as an engine builder not one iota, its just that there are scmucks out there that attempt to screw guys like me everyday. (BTW, I did not percieve you like that.) I have made my policies and I must live by them. If I pick and choose then I am not being fair to each person who contacts me.

Also, I was not allowed to send out any drawings back in the day.......Thus no you never recieved them! LOL

Should you ever decide to try my camshafts out, I am quite sure that you'll be happy with what I do.

Have a GREAT Day Ed!

[Scott McMullen]

Damn This a really nice example of people listening to one another.Great Guys!