Okay guys - here's my cam with 1.5 rocker arms

112' lobe sep
.440 / .454 lift
210/216 duration


here it is after 1.6 roller rockers

.470 / .484 lift
212/218 duration
112' lobe sep

I've already got a custom chip that works quite well with the car using 1.5 rocker arms, but i'm worried that i might be running more than the car will like. Could you guys throw me some input? The parts are in the mail already, but I could still return the 1.6s and get 1.5s.


Ty

 

what is it going in?

if you have non-stock heads, and an aftermarket intake, you should be fine with the 1.6's, just be prepared for the tuning to get her running good. that cam is pretty healthy, but not too big, in fact is is smaller than the cam that i ordered with 1.5 rockers my cam is 212/220 .492 .492 112

now if you are doing this on factory swirl-ports that is WAY too much cam.

 

Why would you say that? Because of lift limitations, or flow?

The flow limitations of those heads are OK for that cam. That cam isn't very aggressive but neither are those heads. A friend of mine has a similar cam (214*/224* w/112* LSA) in his 89 350 TBI (truck), and it pulls strong to 5000 RPM. I think it falls off after that from both the heads and the stock TBI combined.

So I'd have to agree on one point, that cam IS pushing the limits of the stock heads.

The lift might also be a problem. The seat-to-retainer clearance probably won't be enough, if there is any at all. Even with the 1.5 rockers, you're pushing the limits enough that you should check the clearance.

 

i say that because the factory heads are designed to be better suited for a lower torque curve, and that cam on a 305, puts your power band higher than where the factory stuff is going to want it, yes it will work, but it won't work to its potential. on a 305 (not a 350) that cam will make power clear to 6k, by 6k, the swirl ports are way out of where they are efficiant. on a 350, that is a whole diffrent cam.

 

Right. But if it is a 305 (since he hasn't said what it is), the same heads will "flow more" to feed a 305 than it will a 350 because (of course) a 305 needs less air/fuel.

Plus, if you notice, I said the cam that's in my friend's truck is more aggressive than the cam TP355Z is talking about. 4* more duration on the intake, and 8* more on the exhaust.

You said
It isn't "WAY too much". It is, however, pushing the limits.

 

are the head on the 350 TBI trucks identical to the 305 heads?

 

my mistake gentlemen. lol. the heads are off a 1987 boat motor, which translate into a truck head. I had the wide-stem exhaust valves replaced with narrow ones, gasket matched, ported and polished the heads, so they flow ok. I've got guide plates and rocker arm studs too, with the stock rocker guides in the heads drilled out. My concern was regarding the computer primarily, thats all. They're not a swirl-port or vortec head, so i shouldn't have clearance problems. *i think*

Ty

 

Are you going to be running guided rocker arms ? If so lose the guide plates or you'll be tearing into the engine again to replace some valvetrain componets.

Steve