44mag

iTrader: (1)

alot of the bigger cams these days like the tsp ms3 and trex are putting down more peak hp numbers than alot of heads and cam cars. i understand that with heads and cam the power will be in a more useable rpm range but what is going to be faster down the quarter mile a cam only set up making say 425 rwhp or a heads and cam set up making the same power? given the proper suspension, gearing, traction, etc. would there be much of a difference in ets?

racrx

VERY GOOD QUESTION!!!!!!!!! experts please!!!

Patrick G

iTrader: (14)

If the rwhp is the same for each car and the gearing and suspension is optimized for each motor's unique power band, they will ET the same. This is purely a racing statement. From a street standpoint, the heads/cam vehicle will make lots more rwhp and torque in the 2,000-4000 rpm range than the cam only car and would most likely make its 425 rwhp at a lower rpm than the cam only car. This would make for a much more enjoyable ride.

Let me put it another way (hypothetically):
425 rwhp Heads/cam car would make peak power at 6000 rpm, peak torque at 4500 rpm.
425 rwhp Cam only car would make peak power at 6300 rpm, peak torque at 4800 rpm.
Heads cam car might make best ET with 4.30 gears.
Cam only car would make best ET with 4.56 gears.
ET should be the SAME! (just two different ways of approaching the same goal).

44mag

iTrader: (1)

thanks patrick g! i kinda figured that was the answer. anyone else wanna chime in?

PBO

I can agree with what Patrick said, but also if you want to go with a head and cam package, I would think that the heads would hold up better. They would be built to run with the cam that you have, and they would hold up a lot better. With the LS1 we have shotty springs, and the pushrods would go for a change as well, thats why im going to go with the SLP head and cam package, and get the chromeoly pushrods while im at it since the heads will be off and i can just yank the others rods out of there. So that way you have the best of everything and you dont have to worry about anything breaking as easily. But the is just my OPINION.

Dracus

I've never really heard of anyone destroying their LS1 heads. Also, you don't need to take the heads off to do a cam swap on the LS1, and pushrods can be swapped easily when you swap springs (add like 2 minutes to your install time to take the old pushrods out and drop the new ones in).

Anyway, back on topic:
Can someone please explain to me why having better heads gives you power earlier? Thanks in advance

Patrick G

iTrader: (14)

Well said, but anyone who makes 425 rwhp with cam-only will have upgraded springs, pushrods, retainers and locks to much higher quality pieces than OEM. The only difference between heads/cam and cam-only would be the more limited airflow of the stock heads. Stock GM heads, valves, and rockers are very robust. The springs, retainers and pushrods are weak links. Same for OEM timing chains and oil pumps. They suck. Cam-only applications making 425 rwhp will usually change these items as well.

Patrick G

iTrader: (14)

More airflow means more power at the same rpm. Said another way, a head that flows 20-30 cfm (across the valve lift range) vs. stock heads will make over 20-30 rwhp at the same rpm. It's simple math. If you make 400 rwhp cam-only at 6000 rpm, you might make 425 rwhp with heads/cam at the same rpm. The heads/cam combo was already at 400 rwhp by 5700 rpm. It's packing in more air for every stroke of the piston, therefore it makes more power...period!

c54fun

iTrader: (-1)

You usually see 20-25 more rwhp with a nice set of ported heads over stock with the same large cam setups ! I have not seen much over 450 RWHP with H/C and 425 with Cam only!

The main key when adding a cam it to get Headers to get the exhaust out more efficiently !

Dracus

Agreed 100%.

Thanks for clearing some things up guys

XTrooper

I see two big advantages of a H/C package over a cam only installation. First, you don't need an insanely big cam to make big power in an H/C car. Second, if you decide you want an insanely big cam at least while putting up with it you'll know you're getting your money's worth. With the cam only, you'll have the same issues to deal with while never realizing the cam's full potential.

TD's z

COULDN'T HAVE SAID IT BETTER

so say you have a car and all of your susp. is done you have a huge cam and make a bunch of power and go fast

now you take the same car throw a set of good heads on there and a tune you will make more power and go faster... no brainer
Tony

Avengeance

iTrader: (4)

Doesnt a H/C car put down more rwtq then a cam only, I thought they did, and that would be a BIG factor.

dug

iTrader: (10)

Yeah ported heads make more torque. Up to 20-30 ft/lbs more. This will make the car funner to drive. Probably feel similar to the change of adding lt headers to a stock engine.

luv2spd

iTrader: (1)

I don't remember what stock felt like anymore! lol Anyways, I think the H/C combo is obviously gonna give you more hp over a huge cam only car, and it will have a much better power range for the street.

dug

iTrader: (10)

Yeah me neither. It was weird, after installing the cam and headers, the car didnt feel that much faster. Now its starting to feel slow again.

Avengeance

iTrader: (4)

LOL.. Im with ya.. RIGHT after my car dynoed the 397rwhp and I was starting to like the power it was making... I went for a ride in my friends turboed firehawk... ruined me.

1Hawk

If you have a big converter or launch high in a six speed then what a motor makes around 3000 rpms shouldnt matter. i made 401.6 cam only through an auto with a SY3500 converter. i have raced some heads cam cars with comparable power and It all boils down to the launch on who wins. Id say converter is the biggest player in Et's. i got beat by a friends car who made 388rwhp with a vig 3800.

XTrooper

Definitely. Stall speed has a huge impact on your 60' times and your final ET even when launching from an idle!

Magred2001vette

iTrader: (2)

Yea, I've road in that car and it is damn quick for a cam only setup in an automatic....now Elie, when are you going to throw a set of stg 2 heads on that with your 90mm LSX setup to finish it off? I think I'll be calling you soon for an apt to put heads on....later bro.