I'm in the very early planning stages of engine work on my 305. The engine size is potentially beside the point though - if you don't think so, related to my question, please say so.

In looking at a replacement cam, what lift/duration specs should I stay under so as to not affect driveability too much? I've read that with TPI set-ups (mine is mas-air) a too radical cam can affect vacuum in a negative way. Bottom line is that I want to maintain a rather smooth idle (a reasonable rumble is ok) and good driveability while maximizing my cam selection as much as possible with these limitations. Probably going to be sticking with the 305 and TPI, has a manal trans. Computer tuning is not out of the picture - in fact I hope to include that in the build-up to help get the max out of any changes I make.

So what do ya think?

K

 

For a 305, I would stay below 220* duration on the intake side. That would also be a pretty big cam for a 305! For what you want look for something in the 212-218* duration @.050. Find one with a FI friendly LSA of 112-114. That will keep your vacuum signal at idle. Actually, since you are running MAS, a little less LSA would give you that lumpy idle so many people love without too much negative side effects. Look at Comp Cams website for cams, then post if you want to verify a good selection. Have fun.

BTW, learn to tune your own PROMs now. That way you will be better off once you start doing engine work...

 

Hey - Thanks. The PROM tuning info here is great - I just need the time to sit down and do some reading - time seems to be at a premium for me lately. I've got a laptop - maybe it'll come in handy for tuning purposes.......

So, anybody else have thought on my cam question? Here's another question - any good way to find out, with some certainty, what cam I curently have in my stock engine?

K