Help me pick a cam!

J-bird

J-bird

Member
Fist off this is not syty related so mods please move if this is not the appropriate section.

I have been helping my brother build a lotus super seven over the past year, using some take off parts my ty and junk yard parts (budget build). We have finished the frame, suspension and brakes, and now have a motor to go into it soon.

The motor is a non balance shaft long block with a set of vortec heads and the edelbrock carb intake manifold and a 500 cfm carb. We are now trying to speck a better cam for this motor, and I haven't been able to find much information. He is trying to use a bigger cam with the stock valve springs and retainers, but I am having a hard time figuring out what lift the stockers will take.

What would you guys suggest in this situation. I was trying to talk him into a comp 415 or 422, but I'm pretty sure that those cams wont work with the stock springs.

any information will be very helpful!!

Thanks,

Jeremy
 
BoostedSUV

BoostedSUV

Active member
Re: Help me pick a cam!

A Crane Compucam was recommended to me when I thought about using stock heads/springs/valves/tune. It's a little steeper than stock but not too aggressive. I never actually checked the specs so I don't have any other info... I don't know how well it would work with vortecs since they flow differently and are good for higher RPMs :dunno:
 
dgoodhue

dgoodhue

BuSTeD 4.3
Re: Help me pick a cam!

J-bird said:
He is trying to use a bigger cam with the stock valve springs and retainers, but I am having a hard time figuring out what lift the stockers will take.
Click to expand...

My memory (usually pretty good) says the max lift is about .480 on stock Vortec Springs.
 
J-bird

J-bird

Member
Re: Help me pick a cam!

Sy#2661 said:
My memory (usually pretty good) says the max lift is about .480 on stock Vortec Springs.
Click to expand...

Can I use an after market spring and get more lift without cutting the heads? or is it necessary to cut the heads on all non stock springs?
 
dgoodhue

dgoodhue

BuSTeD 4.3
Re: Help me pick a cam!

J-bird said:
Can I use an after market spring and get more lift without cutting the heads? or is it necessary to cut the heads on all non stock springs?
Click to expand...

You can use Ls1 behive springs and not have to cut the valve spring seats. I think that you have to clearance the pushrold holes if your using 1.6:1 Roller rocekrs.
 
dgoodhue

dgoodhue

BuSTeD 4.3
Re: Help me pick a cam!

I think that is too much lift for stock springs, I rather error on the side of caution. Stock unport Vortec, don't really flow any better past .450 anyways. Maybe something like this.

http://www.summitracing.com/parts/CCA-18-124-4/

If you really want to get more rev's without a turbo, I would break and get better valve springs.
 
Icarus-54

Icarus-54

Donating Old Member
Re: Help me pick a cam!

Isky cam # 252/257,.450 int. .465 exh. 204 int. 209 exh. @50
good torque--computer friendly
Jack
 
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