8/71 blower build, cam help?

[Johnny Blaze]

After years of dreaming, we are building a blower motor for our Pro Street 55 Bel Air. Starting with a GEN 6 454.

Looking for cam advice.

The car will be a cruiser, and we want it to have that nasty lpey / surging idle you see the nostalgia fuel cars have at the Hot Rod reunions.


I sent a request to Howards, and they came back witha pretty healty came with 243/255 duration @ .050" but with an LSA of 114.

I would think a tigher LSA would give me the idle we want more so then the wide. Am I right or wrong?

Thoughts?

I've never built a blower engine before, and have been trying to do some research, but not really finding anything discussing this.

[Johnny Blaze]

I might have found the answer.

I read that the surging idle is caused by the engine fighting boost at idle. So an overdrive set up as apposed to underdrive would give this idle, regardless of cam.

Does that sound correct?

[maritimemafia]

Go here, these guys have real input. http://www.performanceboats.com/v-drives/9260-want-blower-surge.html

[sam 74]

you want the wider lobe sep for boost, the surging idle is from an over driven blower, if thats what you're after figure what you need pulley wise and over drive it a little.

[maritimemafia]

Hey JohnnyB, are you satisfied with Your answer? How you gonna' get that surge? tell us!

[Johnny Blaze]

Well like I stated above, I quickly found out the surge was from an overdrive set up.

After talking with thr blower supplier, we decided to stay underdriven for drivability.

So, no surge.

As far as lsa, BDS suggests 110, Dyers says 112, lunati, howards and comp all say 114.

I decided on a cam with 114. Decent amount of duration, I'm looking forward to hearing it run.