TravisMcGill2000

iTrader: (2)

I wouldnt get so caught up on dyno numbers. You could make 400rwhp and still only b in the 12s. How much work is goin into your heads. How hard are u wantin to turn it. The 503 will make power up to 6300 to 6500 if the heads are done right. The 306 could pull up to 6700 or so. Both cams will make good power and proven to work. If your mainly gona drive it on the street i would do the 503 for the low end power and tq. hopes this helps

TravisMcGill2000

iTrader: (2)

Both cams will like compression. So the higher the better. I would run .026 head gaskets.

LSWHO

iTrader: (1)

If your area doesn't have good gas, there's a good chance this could slow you down more than anything. KR will go up with similar gas and more compression. So a tune is pretty important... or 93 octane.

95formulalt1350

not sure how well the heads are orted but im considering taking my other stock lt1 heads n semdimg them to le and have them ported to the le2 but which cam should i go with those le ported heads. n like i said ive got both the 503 and 306 cam?

gatorhead

iTrader: (4)

Seems to me if LE is doing your heads you would want him doing your cam too

camar0corey

iTrader: (22)

If you have both of those cams in front of you, and you are going to have LE do your heads, sell both cams and order one from LE to match your combination then.

mguidry629

iTrader: (6)

He said he has access to both cams, 503 & 306. He's not buying a cam, he's trying to decide between the 2.

OP, I think the answer is in here already. If you want a cam to make power from 2500-6500 then go with the 306. If you don't want to spin quite that high, 2000-6000, then go with the 503. It'll have more low end torque.

Or do what camar0corey says and sell them both to get an LE grind.

LSWHO

iTrader: (1)

306 will need more than 6500rpm.

503 will need more than 6000rpm.

TravisMcGill2000

iTrader: (2)

if le does the heads go with the 306

crazybird

Op i am running the le3 heads on my car along with the 503. I still dont know the full potential of those two together cuz i have not tuned it yet but as soon as i get it tuned ill see what ive been missing. I was going with the gm847 almost same as the 306 but i wanted drivility as my car is a dd and i traded my gm for the 503. Its up to you. Why not try one for some time if you dont like it go for another

95formulalt1350

yea i figured id go with the 503 to because my car is a dd to but thanks everyone for the help and ill prolly end up getting both cams beacause i got a back up lt1 motor laying around lol

chas010

iTrader: (3)

My 503 cammed lt1 likes to rev to 6600 and runs high tens