I'm on a really tight budget. i have some standard chevy heads on my rebuilt 350. the heads are 74cc heads. would it be cheaper to have the heads port and polished or get some newer heads? i live in rochester ny, who does port and polish jobs around here? if i can pick up 10-30hp from porting the heads for 200-400 bucks that would be nice. anything over 400 and i could just buy some vortecs right.

 

Right.

Those old smogger heads are trash. Don't spend a dime on them.

It's NEVER "cheaper" to "have heads ported". Porting costs by the hour. It takes lots of hours. You want somebody that knows what they're doing, for best results. So you have to pay a high hourly rate for a knowledgeable experienced machinist (lots of $$$$/hr) to work on your heads for lots of hours. Lots of hours times lots of $$$/hour = lots of $$$$$. No way around it. Not worth it unless your cores are worth sinking LOTS of money into in the first place.

If your budget allows Vortecs, and a manifold to match, that'd make a whole lot more sense. Just go to the junkyard and get a set, drop it on what you've got with the right manifold, and ditch those smoggers. You could probably do it for $600 including fluids, gaskets, and a few "might as well"s that you'll probably run into.

 

Yea vortecs are starting to look like the smarter choice. I'm gonna wait to buy those cause i'm just gonna do the cam at the sametime. I just got done buying a bunch of stuff. I bought carb calibration kit, msd 8.5mm wires, kyb gr2 shocks all around, eibach pro kit, sohn lower control arms, sohn pan hard bar, and i'm getting ready to buy some 1.6 roller rockers. probably buy those tomorrow.

 

Probably not worth it, and likely not a good idea with unmodified Vortec heads.

 

Exactly:

HUGE difference between stock rockers and non-rubber roller ones; VERY LITTLE difference between 1.5 rollers and 1.6 rollers, as far as making power.

Plus, with Vortec heads, there's a limit to lift, meaning you can get yourself into trouble by increasing the lift; they don't flow much better at higher lifts anyway, their design promotes good low-lift flow instead. In other words, large risk or expense, small or negligible gains. Not a good plan.

Go with 1.5s. I'd recommend the Comp Pro Magnums. (1300 series) Not aluminum, if it's going to be on the street.

 

i'm getting the 1.6 roller rockers for now just for the mild cam stock head combo. right now i have regular non roller steal rocker arms. i won't be getting the vortecs for a while. right now i'm just doing as many cheap mods as possible.

 

1.6 roller rockers aren't what I'd call a cheap mod, especially in terms of improvement/$.

 

well considering i can get some new roller tip 1.6 rockers for 75 bucks.. i'd call that a cheap mod as opposed to 600 bucks on a set of new vortec heads, 180 bucks for the intake manifold, and another 180 bucks on a cam. I'm not looking for much, just a little at this point.

 

Roller tip rockers are a different matter. Do you know if your stock heads are going to handle the extra lift from the 1.6 ratio though?

 

i don't know for a fact, but the cam if very mild so i'm sure i can handle a little more lift. Think thats a bad way to go about it? theres really no way to know cause i didn't build the motor. which would benefit me more the xtra lift or the less drag from the roller tip?

 

If you don't know for sure, and you're unable or unwilling to check, you're better off sticking with the stock ratio.

 

where do you gain power when purchasing roller tip rockers? Do you make power with the added lift or with the roller tip design? Or is it both? If so which is more benefitial? To be safe i could go with a 1.5.

 

The biggest advantage of roller tip rockers is the reduction in the side-loading of the valve, which reduces valveguide wear.

 

does this free up any horsepower? my question is when ppl go to buy aftermarket rocker arms, what gives them more power from the rocker arms the lift or the decrease in friction from the roller tip? lol

 

Not really; it mostly reduces wear on the guides.Mostly, the improvement in lift, and most especially, the CONSISTENCY. Stock rockers, if you measure them even without load, might measure anywhere from about 1.41 to 1.46 ratio, with the majority being around 1.43-1.44; under load, the "ratio" is quite a bit less, sometimes as low as 1.38, because they bend so bad even with weenie stock springs.

The other SIGNIFICANT advantage of roller-trunnion rockers is lower oil temps. I've never measured it myself, but people claim that on the dyno, oil temp can be between 5 and 10 degrees cooler with rollers, because the ball fulcrum generates SO MUCH heat.

Which is all why going from stock rockers to REAL ones, is where the majority of the benefit is. Going from 1.5 to 1.6 of the same design makes less of a difference, by far.

 

hmm so even if i went with 1.5 roller tip rockers it would be good. more consistant ratio and less friction, which in return you say can lower oil temps. i should just get these cause it's better. even if i don't make more power. I've pretty much reached the limmit on cheap power mods. i guess i'll just have to save and go for the heads and cam next.

 

No, he said roller TRUNION rockers can lower oil temps. Roller tip ones won't.
Roller tip ones just reduce side loading on the valve stem.

The roller trunion ones sofa mentioned are $300. IMHO they don't give $300 worth of benefit, there's better ways to spend your money. I just use $70 roller tip rockers from proform/summit/CNC motorsports. I bought these because the roller tip is a nice benefit, and I needed cheap SA rockers, and CNC motorsports was the only ones I could find with all the features I needed.

Spend your money on heads and cam first, rockers can come later.

 

i know i just want to break into the thirdteens this spring and money is tight. I'll just save. i have a calibration kit, new wires, and some suspention mods. maybe i can tune out a little more power and launch better and get that 13.99...

 

Don't forget to mention that the pushrod slots in the heads have to be modified on most heads to run 1.6's (and sometimes the valve guides as Ape said).
Stock rockers and pushrods at work*.

*everything else ain't stock...

 

why do they have to be modified?

 

The pushrod is located closer to the rocker stud on 1.6's . If the pushrod slot isn't lengthened they rub the head/guide plate. Just ask Sonix.
If the 1.6's increase the lift of the valve enough and the retainers hit the valve seals, the guide must be made "shorter" to prevent this.

 

Yea, I was just about to say, i've had that happen to me. I did elongate the pushrod slots, but not enough it seems. (.530" lift).
They wore a little "slump" into the slot. The pushrod tilted and went into it's little "slump" area, got stuck, and broke in half. Twice. Then I realized "that ain't right!" and fixed it by drilling out the slots and going to SA rockers.