Cam questions

[ZackTheImpaler]

Ok so now that I've got a new soon to be DD I can focus on what I've been wanting to do, hotrod out my 720 as much as possible with the existing l20b.

 

If any of you follow my builds you know that I have the pumpkn210 with me on everything so what I don't know (which is alot) he does. But I've still got loads of questions!

 

 

So we are going to build a gnarly intake to mount 2 38/38's on, and possible tranny swap.

 

I lurk alot and have been reading alot on cams but I still am not quite sure what swapping out to a performance will fully do for me?

 

What kind of cams should I be looking at? When my Rosie gets an engine swap, she will be what I drive to work and such. Dottie (the 720) is going to just be for fun out in the secluded mountain roads. I will probably drive her around every once and awhile because she is sweet tits. I don't live in a very populated area so no traffic. I can rev high and it's ok.

 

 

Should I change my valves and rocker arms as well? Is it worth buying the a kit?

 

And what companies should I be looking at?

 

 

I know that I could take my existing one in and get it cut correct? So is it worth it to get a new one?

 

 

Sorry for all the questions. But I need to know these things! I'm very serious about anything I'm doing and put alot of money in my vehicles, so please take me seriously.

 

 

And here is something for taking the time to read

 

[ZackTheImpaler]

So.....was my picture not enough offering to the great Ratsun gods to get help?

 

 

I know you know

 

 

But I don't know

 

 

But I wanna know

 

:unsure:

[datzenmike]

Rule #1

 

Never, never, never, never, never over carb or over cam your engine. The more you do the more it will only run properly at above 5,500 RPMs. If you trailer the truck to the mountain roads then go nuts. If you have to drive there it's better to keep it street able. This is not to say you can't build it up and still have some fun.

 

The stock cam is 0.413" lift at the valves and 248 degrees duration. I believe that if you keep the lift near 0.480 you can still use the stock springs, and that saves a lot. I've been told that some of the Roadster valve springs fit and are stiffer and these will allow higher revving. Increasing the duration to about 270-280 is reasonable and can be driven on the street. By on the street, I mean they idle fairly good, and have enough low speed torque to pull away from stops without revving the shit out of them. Stop and go is no fun in a cammed truck.

[ggzilla]

Changing the cam and adding carbs is not going to give you a 10% power boost.

 

More bang for you buck is putting a lower gear in the rear end along with an overdrive 5-speed. If you've already got a 5-speed, fit a used pumpkin from a 620. It'll rev a bit higher on the freeway, but accelerate faster from a stop. Easy can gain 10%.