Cam recommendation question
Thread Starter
Racer
Joined: Aug 2001
Posts: 473
Likes: 0
From: Raleigh NC
Cam recommendation question
My engine builder gave me the parts list today and he is recommending the Comp Cams Magnum 270H with 224 duration and .510 lift.
I want something very streetable, but I also want the nice lope at idle. Is this cam gonna give me what I am looking for?
I want something very streetable, but I also want the nice lope at idle. Is this cam gonna give me what I am looking for?
Safety Car
Joined: Aug 2000
Posts: 3,909
Likes: 26
From: Clymer PA
Re: Cam recommendation question (hudman)
That is a very mild cam for a big block. Personally I don't like the lope in idle. I'm running the Comp Cams 294S solid flat tappet cam .595"/.595" and think that it's a pretty mild cam also. I idle my car at 1500RPMs to get rid of the lope and make it snappier. However if I were to idle my car down to 1000RPMs...the lope in idle is pretty mean.
What heads and rear gears are you running? I would definitely shoot for a cam with around .550" lift at the bare minimum.
Also keep in mind that the Magnum cam is an old grind. Comp Cams Xtreme Energy cams are a newer grind. The Comp Cams XE274 has .552/.555 lift....that's about .040" more lift. It's also a split duration cam with more duration and lift on the exhaust side which will help if your exhaust is somewhat restrictive.
[Modified by bence13_33, 4:54 PM 3/3/2003]
What heads and rear gears are you running? I would definitely shoot for a cam with around .550" lift at the bare minimum.
Also keep in mind that the Magnum cam is an old grind. Comp Cams Xtreme Energy cams are a newer grind. The Comp Cams XE274 has .552/.555 lift....that's about .040" more lift. It's also a split duration cam with more duration and lift on the exhaust side which will help if your exhaust is somewhat restrictive.
[Modified by bence13_33, 4:54 PM 3/3/2003]
Thread Starter
Racer
Joined: Aug 2001
Posts: 473
Likes: 0
From: Raleigh NC
Re: Cam recommendation question (bence13_33)
Bence-
My heads are the original 390 hp 3917215 casting small chamber oval port heads. I am going to keep the stock size valves, but go with roller rockers.
The rear end is a 3.36 posi.
My goal is to be streetable, make plenty of vacuum, and sound great at idle. It has to have some umph, but the only action it will see is on the street. It will never go to the track.
Should I push him on the cam for a bigger lift?
My heads are the original 390 hp 3917215 casting small chamber oval port heads. I am going to keep the stock size valves, but go with roller rockers.
The rear end is a 3.36 posi.
My goal is to be streetable, make plenty of vacuum, and sound great at idle. It has to have some umph, but the only action it will see is on the street. It will never go to the track.
Should I push him on the cam for a bigger lift?
Race Director
Joined: Dec 1999
Posts: 11,092
Likes: 990
From: Sierra Foothills CA
Re: Cam recommendation question (hudman)
Hudman,
The choice is obviously yours but I'd like to make a couple of suggestions-
1. Spend a few extra $$$ & up the valve size to 2.19/1.88. Those heads(same as mine) will support alot more flow if you do without suffering any ill effects.
2. Put a bit more cam in to go w/ #1- with compression at 9.5 I've been running a Crower flat tappet hydraulic cam w/ .517/.529 lift & 220/226 duration @ .050. With this combo, a good carb, a stock torque converter, & 3.55 gears I had more torque than I really needed along w/ plenty of vacuum. With track tires I had no problem running mid-high 12's in the 1/4 mile and still had a very docile street motor. Oh yea- it has a definite idle too.
I've made a few small changes since then but trust me- you can reach your goals & have alot more power at the same time w/ this or any similar combo. Good luck. :cheers:
The choice is obviously yours but I'd like to make a couple of suggestions-
1. Spend a few extra $$$ & up the valve size to 2.19/1.88. Those heads(same as mine) will support alot more flow if you do without suffering any ill effects.
2. Put a bit more cam in to go w/ #1- with compression at 9.5 I've been running a Crower flat tappet hydraulic cam w/ .517/.529 lift & 220/226 duration @ .050. With this combo, a good carb, a stock torque converter, & 3.55 gears I had more torque than I really needed along w/ plenty of vacuum. With track tires I had no problem running mid-high 12's in the 1/4 mile and still had a very docile street motor. Oh yea- it has a definite idle too.
I've made a few small changes since then but trust me- you can reach your goals & have alot more power at the same time w/ this or any similar combo. Good luck. :cheers:
