Hey, I am trying to decide if doing a cam in my car makes any sense. My car is an 85 Z with a T5 and '89 MAF. Since my car was originally a TPI auto, it has a relatively good cam stock. (no peanut cam in '85) (202/206 Int/exh, .403/.415 Int/exh) I also have 1.6 rocker arms making my specs (215/220 , .430/.443) 114.5 LSA

My TPI is ported with SLP runners. I also just got a set of 081 heads that had 1.94" intake valves installed along with screw in studs and guide plates. Basically, I was planning on doing a little porting to the heads and slapping them on. I just would like to know if getting a bigger cam would be worth the money? I think the hardware on the heads that I bought is LT4 stuff, so I shouldn't need to upgrade that. That means the costs should be limited to a timing chain set, and the cam itself. Computer tuning it not really a huge issue since I have prom burning equipment.

All opinions are welcome! The bottom line is that I do not want to spend money that won't make a reasonable difference on a 305.

 

I know the 305 doesn't get much respect, but in my book a V8 is a V8 is a V8. With all that done, should be at least 3-4 tenths being on the conservative side. Is that worth it to you?

What are your goals for the car?

 

Could you be more specific? 3-4 tenths would be good, but I already have 215/220 int/exh duration. While More lift may help me, I am getting the feeling that more duration is probably not a good idea on a 305 with ported stock heads.

that said... I noticed this cam: Comp Xtreme Fuel Injection 260XFI has these specs w/ 1.6 rockers : 216/223 , and .499/.493

Seems like a good one, but I don't want to drop a couple hundred bucks on something wont make much of a difference.

 

How much TPI porting are you talking here? Just the runners and plenum or are you planning on siamesing the base as well and getting it all to match up with out any steps or obstructions?

What I would do is, get that all nice and ported and then take it to a dyno. There you can see how much more rpm you now have, so you can see how much more duration you can get away with.

Now with the heads, are you doing it yourself or a having a shop do them? Personally, if it were me, I'd look for a set of 113 aluminum vette heads and have them ported out instead. If a shop is doing the work regardless, it might come out cheaper for the aluminum heads (easier and faster to port) plus the advantages of having the lighter heads. Have them flowtested and with your dyno, that will give you an even better idea of the cam to get.

 

On a side note, if you had your automatic and good stall, you'd be 2-3 tenths ahead of your 5spd with the same mods. I think manuals are fun, but a properly stalled/geared/H/C car is even more fun as you blow the doors off the other guy with a manual with a big gulp in your hand.

 

A modern cam profile will make more power than the one you are running.

 

I ported the plenum, slp runners. I got a few millimeters off of the stock base, but I do not plan on fully siamesing it.

The head porting will be done by me, and probably only minor since I do not want to screw anything up. I dont have to deal w/ machine work since I bought the heads after they already had some work done to them. No go on the aluminum... too much $$$.

As for the Auto.... BLAH! Dumping the slush box was the best mod I have done. The car is 1,000,000,000 more fun to drive and I get higher mph at the track than 350 auto cars. if only I could launch the beast without fraging the T5 or the 10 bolt I would be golden.