377Z

iTrader: (1)

They are the 67cc chambered S/R's with 1.94/1.50 valves. My guess is that they would currently flow about like the 305 torquers (same valve size--around 213cfm @ 0.500")?

What I have--stock bore 350 with 3.75 stroke, forged TRW flat top pistons, 5.7 rods. Cam is a Comp XE274H. If I new what I know now, I'd have skipped the stroker stuff and put that money towards better heads (and a roller block, plus maybe pistons with a slight dish, but mostly concerned with the heads). 3" cat back.

What I plan to still get--I will either get coated Hooker shorties or SLP stainless & a 3" cat for exhaust. Intake will be either converted LT1 or HSR. Rear gear will be 3.27, torque conv. stall speed I'll pick w.r.t. the motor (and I'll prolly end up choosing another cam to match the head flow).

Bottom line--I really goofed on the heads (and cam)--what can I expect from working the bowls, valve guides, and gasket matching? Could such basic work on these castings get me to around the 240 cfm @ 0.500" ballpark? I know its been done, but I've never done any porting before.

Won't be racing, this is just supposed to be a hot street car so the combo can be a bit less than ideal as long as its not as horribly mismatched as it is now. Am I wasting my time with these heads?

Damon

Probably. I don't trust custom port work unless the shop will provide flow bensh readouts both before and after. Anything else is just educated guessowrk. I had a 400 that went low 13s @ 104 on street radials or thereabouts with those exact same heads, no port work, and a very mild cam (Carbureted intake, headers, the usual bolt-ons). They're not junk. And they're what you've got right now.

Match the valve springs correctly with the cam and you'll still get decent results- maybe even surprise yourself. Don't bother lifting the valves to the moon (.500 or higher) becuase you just won't get much increase in flow from them (unported) over about .450" lift.

You can get better heads later as money permits and learn a BOATLOAD about tuning your combo in the meantime.

When I switch from the S/Rs to a set of Iron Eagles (both box-stock) I immeditely went a full 3 tenths and 4 MPH quicker with no other changes, by way of comparison.

five7kid

iTrader: (14)

S/R Torquers, might be worth the effort.

S/R's, probably not.

But, since it's only intended for street, they may be okay anyway.

377Z

iTrader: (1)

Thanks for the replies guys.
Damon, glad to hear from someone that has used them; question, what were the specs on the cam, and what intake did you use?

My current cam's lift is 0.480/0.490 int./exh. (with 1.5 ratio) and I don't think any cam I will use will go to deep into the 0.500's." (hydraulic).

five7kid, when I did a search I noticed you have experience with the Torquer 305's. What flow (@0.500" lift) do you think would be reasonable to expect with an average-guy home port job?

Is there any difference between the S/R's and the S/R torquer besides valve size? I am under the impression that ports & chambers are the same, no?

five7kid

iTrader: (14)

I assumed 10% over as-advertised.

I was under the impression that the S/R Torquers had different chamber/port shapes vs. "regular" S/R's. I haven't seen them side-by-side. I had a set of S/R's in '97, but they were gone at least 3 years before I got the 305's. So, I can't say how they compare.

F-BIRD'88

Go ahead and port them your self. yes you should be able to hit 240cfm with the 1.94 valve.

Se Rhuarc31's recent post in the TPI board for a full
write up.

AllGoNoShow

The s/r are s/r torquers with the smaller valves, same ports and such.

I have a set of stock Dart s/r heads on my 355(Same heads as World just Dart use to put their name on em)...with a 205/216@.050 cam I got a 14.7@97mph with a 2.3 60ft time in an 81 z28...the horsepower is there with the 97 mph trap speed which is pretty good for such a small cam, with slicks I could probably squeech out a 13 second pass. I really like these heads, sure beat stock heads. I'm not sure I would buy these heads now(previous owner did) since there are other great deals out there but i've been happy with them.

You could always put in some 2.02s/1.6s espically if you end up nicking a valve seat. Everything I have heard and read say these heads respond great to even mild porting....the valve guide bosses are pretty big I'm sure theres a good amount of air...and there is a noticable ridge in the bowls under the seats.

377Z

iTrader: (1)

Thank you all for your responses.

I saw Rhuarc30/31's posts about the L98 heads, but he sounds like he has considerable skill (260+ cfm from factory heads...I wonder if his real name is Smokey Yunick), I've never done this; but you've got to start somewhere so I'll give it a go.

I'll try porting these heads since they are not a dead end as I thought. It feels good to avoid another $1000 bill, especially when I still have so much stuff to get still.

Thanks again.

Damon

My cam in the back-to-back testing was a very mild Crane Energizer 266 cam. 210/210* duration, .440/.440 lift (.470/.470 with the 1.6 rockers I used on both heads). It was quite a difference considering the very mild engine specs. On a more aggressive motor the difference would probably have been even greater.

five7kid

iTrader: (14)

Are you completely sure about that? I am not, and given what you say below, I'm not sure that you're not operating from faulty data.

Actually, World had Dart cast their (World's) design for them (World) in the early days. They (World) have their own casting facilities now, and have ended their relationship with Dart.

AllGoNoShow

I am 90% certain that the s/r are the same heads except with smaller valves...I emailed one of the techs from world castings to figure it out so we'll know in a day or two...hopefully I won't end up putting my foot in my mouth!

While I was somewhat unsure of the exact relationship between World and Dart alls I know is that my heads say Dart s/r on them(not world) and the previous owner's recipet says Dart s/r heads and everyone has told me these are the same exact castings as the World S/Rs except with Darts name on em....my comparision and experience with the s/r's still holds true regardless of the exact affiliation that use to exist between World and Dart.

AllGoNoShow

mike@worldcastings.com says "hey Nick, yes you are right valve size is different & the rest is basically the same. Corvette Mike"

If you know what your doing with a grinder I'll bet you'll see a solid 25hp increase, take pictures if you do too cuase I will be prorting my heads latter in the summer!

five7kid

iTrader: (14)

"...basically the same."

Okay, that's good enough for me.

Now, Jeg's says the S/R Torquer 305's are "not Torquer style". Meaning, they're S/R style. I guess that means they have 1.94/1.50" valves (as well as smaller chambers).

At any rate, I agree with the statement that they need help in the bowl and guide areas. I can't believe they let them leave like that.