Well its about that time that i have to pick out a cam. I have a few in mind and have decided to maybe go a hair smaller than i was originally going to. Heres the combo
-350, .040 over
-4340 bottom end, 6" rod, billet splayed caps w/flat top SRP's
-Brodix RR 200's w/ CNC chambers milled to 60cc for 11:1 comp. Titanium retainers, and Bullet double springs good to .600 lift
-Weiand Team G {for now}
-800 DP holley {for now, 750 mighty demon soon}
-Crower Enduro 1.5 roller rockers
-17/8" super comps {i know i know but i got a good deal on them a while back but later when i can afford it ill get some 1 3/4}
-3" exaust w/ flowmasters
-Richmond 5 speed 3.28 first gear
-ford 9" 4.10 gear, detroit locker and moser axles
Now the cam im looking at is a Solid Doug herbert grind. Its specs at 300/310 duration, 254/265 @ .050, .540/.555 lift on a 107 l/s.
How do you think this would run? Any other cam suggestions {no comp or Lunati}This is going in a 73 Nova that weighs 3250 Im looking for mid to lower 11's you think thats enough cam for it? Streetability isnt a huge concern but i have to run pump 91 octane. Im just looking for opinions here so all are welcome. Let me hear what you think. Thanks

Looks like some nice components. You probably already know the advertised rpm limits running that duration with solid lifters. I'd guess around 7K-7.5K rpm. I guess 91 octane is good at 11:1 but I'm sure it would love higher octanes.
All together it's just a shucks that hp and rpms is going to be up there. Is there a weight restriction in the class you aiming for. It sounds like you are desiring a sprcific class sticking with 91 octane.
Sounds like you have another ripper coming out of your garage. I'd love to watch it roar some time. Good luck.
Oh yah. I think it might do 11's especially lightened up car weight wise.

Im running "neighborhood class." No real class, but basically too see whose king of the real street smallblocks around town. 91 octane is manditory because its going to see plenty of street miles between driving to work occasionally, the weekends, cruises, and hopefully car craft summer nats in Minnesota this summer. The DCR with that cam comes out to 7.9 wich if im not mistaken is pretty ideal for 91 octane, aluminum heads and a good cooling system.

Try giving Harold a call at Ultradyne Cams. Sharp guy.

The cam looks a little too big to me. I get a static compression ratio of 10.90 With the cam you've chosen I get a dynamic compression ratio of 7.76 which would run on 89 octane, 91 octane most likely would slow you down. I'd go for a smaller cam with an ICA of 71º to 72º to get the DCR up to 8.2 to 8.15 respectively. You can run a DCR of 8.25 with aluminum heads and 91 octane.
George

My guess is that - that cam will make peak power over 7000, so be ready to buzz it up there. I'd consider a bit less duration, if its a streetcar, with a good set of heads you wont need that much duration to make big power.

See this is my first semi-high compression 91 octane motor. Im still sort of skeptical on DCR, because you guys are the first ones ive met to put so much emphasis on it. I know mathematically, that a motor with aluminum heads should run on 91 octane with an 8.2 DCR. Now is this the case no matter what? I thought that cylinder pressure bleeds off at low RPM but tightens back up at higher RPM because of the lack of time between cycles, thus causing detonation problems at high rpm, but ping free at lower RPM. Am i off base here? Or does this sound right?
Also Ive had my eye on an Ultradyne. 292/301 dur. 259/267@.050, .551 lift on a 110, installed straight up. Harold calls it a daily driver cam for a 350 4 spped. This cam gives me a 7.80 DCR. I know Desktop Dyno isnt the authority on anything by any means but with that cam installed as mentioned it pulled 538hp and 457 ft/lbs of torque wich is pretty respectable and is plenty of power to get me to my goal. BUT im shaky on running pump gas with that low of a duration and 11:1. It almost seems to me like asking for trouble, what do you all think???

[ 05-12-2003, 08:40 PM: Message edited by: Novaguy73 ]

The increased scavenging at higher RPM's Increases the cylinder filling thus pulling in more of an intake charge for higher cylinder pressure.

Combustion chamber design, piston speed, and a host of other factors can all contribute to a engine's propensity to detonation.

The cam that Harold suggests should do fine. Cams above 292º will start trading off torque for horsepower, and we all know torque is what gets us moving. I also think that advancing that cam 4º will increase the DCR from 7.8 to 8.15 and will increase the torque about 10 FT LBS with a small loss of about 5 HP.

Most engines that have a problem with high speed detonation have longer strokes, smaller rod to stroke ratios, and larger piston diameters. You have none of these problems to worry about. A 6" rod will reduce the chance of detonation by increasing the dwell time at TDC for a better flame front propagration at the higher RPM's.
HTH George

[ 05-13-2003, 02:51 PM: Message edited by: run-a-way-69 ]

Still skeptical huh. I run 11.28:1 static with my aluminum head 383 and it's fine on 92/93 octane. I've been driving it last fall and all spring. Sat in a traffic jam on the way to the track, raced it twice on pump gas, and test and tuned on the back roads --- there is no detonation. I've listened, checked plugs, even ran it lean by mistake once and there's no sign of detonation.

My DCR calculates out to 8.44:1, and I am anal about measuring everything when I assemble an engine so when I say 11.28:1 it is really 11.28:1. There is another 383 guy at the Team Chevelle site (Greg - Kazuaki) who runs mid-11's in a Chevelle with a DCR of around 8.8:1. Look him up if you want.

I think you will be happier with a smaller cam. I would suggest keeping the cylinder pressure up (like 200 cranking psi) and DCR around 8.25:1. The engine will be much more responsive and your power will be down where you can use it on the street.

ps. On your low vs high RPM question, I think you basically got it, except cylinder pressure decreases at higher RPMs. Look at Desktop Dyno in the BMEP column and see what generally happens to cylinder pressure at higher RPM. It starts to drop off pretty quickly above the RPM with peak VE. Detonation is more prevalent at lower RPM - like when you lug a car up a hill in high gear. That's why controlling cylinder pressure at lower RPM is important and why DCR is such a helpful tool.

Hope you get some pretty decent gas around Waterloo. Here in Sioux Falls I can`t trust what I`m getting out of the pump. That`s why I built my 496 for 9:1. I don`t want to beat the bearings out of it and ruin the ring lands on the pistons when I run across a bad tank and have some detonation. I think that DCR is good in theory, but when it comes to the real world you shouldn`t trust that the fuel you`re getting out of an underground bulk tank is going to have the octane requirements to support an engine that has been built on the edge of detonation. If you look at the slight amount of horsepower lost by dropping a point in compression, I don`t feel it`s worth the risk. As far as camshaft duration, you can run some large duration numbers as long as you have some very good flowing heads. I think that there`s a reason that you don`t hear alot about DCR elsewhere, if you talk to a few really good professional engine builders, most of them don`t think alot of it when it comes to pump gas engines. Just my 2 cents, Brent