So if scorpion 1.7s give 10 more rwhp than pro mag 1.6s, whats the total over stock stamped 1.5s? This is starting to sound like the best bang for the buck mod for these engines, even more so than LTs.

 

No ratio rockers will give you nearly as much benefit as LTs.

Stock manifolds choke the hell out of these engines.

 

I'm still on stock rockers myself, but I think he's right about them not out-performing LT's. Besides, the headers are probably a key ingredient to the rockers adding the power. There is no use opening either valve more than stock if you can't flow the exhaust out good enough.

I don't know about them being worth another 10 rwhp over 1.6's on the stock camshaft.....I'd guess 5-10 with results varying alot from one car to the next. I don't honestly think I will pick up 20-30 rwhp with 1.7's and a spring upgrade alone vs stamped 1.5's. That would be AWESOME, but I doubt it is that big of a gain.

 

Well LTs give about 30rwhp once you have a tune, these could give about the same (after you already have headers), and cost less.

 

You understand there is not a snowballs chance in hell the LT4 springs will handle a 503 like this right? They wont handle it with 1.5 rockers.

 

The LT4 HotCam springs are marginal even for the HotCam. So, yes, a spring swap will definitely be called for. All you need to do is crunch the coil bind numbers and you'll see what I mean.

I've been running Scorpion NSA 1.7s since 2006 and like them so much I installed them on my son's 96 LT1 Vette last year, except his are 1.7/1.65s do to my ordering error.

I HIGHLY recommend them. High quality pieces, nicely packaged, attractive in appearance, run quietly, not a single problem.

Jake

 

there is more to it than that though....Your heads also have to be able to flow at that much lift...

If you have a cam with .600 lift and the heads quit flowing at .550 then you will not make power and will slow the car down....

 

For myself, I was really talking about gains with the stock cam/heads for now. So the flow would be enough to support the extra lift fine. If I put the 1.7's on with the cc503 later, it will be with ported heads so again the flow should be enough to compliment the added lift.

 

Yep you should be golden then.....what springs are you running?

 

why do most of the 1.7 RR's i see advertised say "BBC" ..is that even going to matter,..as in they will work just like an advertised "lt1" kit for us?

 

Not necessarily.

 

No if you want to run 1.7's you need something that will work on an LT1....scorpion 1026 seems to be what most of the 1.7 guys run...

With that said there are not a lot of guys on here that run 1.7s because when you decide to cam the car MOST lt1 grinds will end up with too much lift for the 1.7 rockers as they are designed for a 1.6 ...

Also if you upgrade to a 1.7 rocker with a stock cam you will need new springs too....and if you ever upgrade cams you will need to find a small enough lift cam to work with your 1.7s or spend another $350-$400 to buy 1.6s at that time

 

duh,on the springs ...i wouldn't do the 1.6's without em'
and with a custom grind LE cam I'm sure its doable to accommodate the 1.7's...and not necessary to replace them to 1.6's i would think.....

 

well you had some questions about some really simple valvetrain issues in your other thread so based on that I felt it was worth mentioning the springs....

Also I am sure Lloyd can do about anything with a cam but more than likely he would recommended going back to 1.6 rocker...as 1.7s not only change total lift they change ramp rates and more....

 

if 1.7 rr's add 30+hp im miles davis

 

make sure you get the patriot extreme dual springs... my brother bolted up 1.7's to that cam in my ol car without checking coil bind and it broke a valve spring and bent two pushrods. The old springs were comp single 130# @ 1.8 installed height.

 

Don't assume... Its not all about lift when you increase rocker ratio... the type of cam lobe is just as important. Some of the newer lobe designs are to agressive for higher ratio rockers. From the research I did the comp xe 230/236 is about the cutoff for 1.7's. My brother had to install patriot extreme .675 lft spring to accomodate 1.7's with the xe 230/236 .510 .520. Best bet is to talk to a professional such as lloyd himself and go with his recommendation.

 

I toyed with the idea of switching to 1.7's at the last minute with my 383 build project. I'm running the comp XFI 280 cam which (small base circle) has 230/236 duration, .577/.573 lift (w/ 1.6) and a 113 LSA. My AFR heads would have LOVED the added lift from a 1.7 rocker. I already had strong enough valve springs (with current cam they measured 150+lbs closed and 420lbs open pressure). I even had the AFR Hydra Rev kit installed in the engine waiting for the 7000 RPM exercise I had in store for her... needless to say but I also had all new & top notch comp lifters, pushrods, and 1.6 (steel) NSA 7/16 rockers.

I did not do the switch, primarily because of the aggressive XFI lobe profile (steep ramps). Even with all my strong pieces the advice I got (Lloyd Elliott was very influential) was I'd be significantly sacrificing valve train stability by throwing in a set of 1.7's. The extra lift may have helped me find 5-10 hp but ultimately could have ended up costing me 10-30 hp from valve train stability problems. Now that's not to say others are not using 1.7's with this same XFI 280 cam - I've noticed at least two guys online who are. I only drive me car once a week at the most and probably could have gotten away with it. But considering how hard the XFI lobes are on valve train components even with a 1.6, AND considering doing the switch to 1.7's would have taken away a lot of the comfortable piston to valve clearance that my engine builder was really happy with, I stayed with 1.6 rockers.

But IF I had made the swtich I can say that I would have invested the $400+ on a set of comp High Tech 7/16" NSA steel 1.7 roller rockers. I would not have cheaped out or gone with any aluminum rocker.

Best be sure you do homework and talk to people who KNOW before doing a switch. I remember I had originally decided to order comp's recommended bee hive spring "upgrade" for the XFI a while ago. FYI this was a few years ago before everyone was raving about Patriot springs. Luckly when I got talking to the guys at AFR in CA about my head order and build info they saw the comp bee hive PN and specs and said no freakin way with that cam. I ended up going with THEIR recommened double spring upgrade which after talking with a few cam experts gave me a lot of piece of mind.

 

I have the Patriot 8401-BSBC dual spring kit...think they will work fine?

Tech specs:
Install Height: 1.800"
Max. Valve Spring Lift: 0.650"
Spring Pressure Closed: 135 lbs. @ 1.800"
Spring Pressure Open: 375 lbs. @ 1.150"
Coil Bind: 1.090"
Retainer Material: Titanium

 

Thunder racing recommended the extreme golds... good to .675 lift, closed seat pressure of 155. The issue is not the lift capacity, its being able to control the valve events with the incresed ramp rates that the 1.7's create on the xe lobe. I would contact lloyd E or Thunder racing and verify with them that the regular golds are enough spring!! Also make sure you get the right valve seals with the spring kit! when my bro ordered the gold extremes, they came with stock size valve seals with the springs... So instead of sending them back and getting the right ones, he opted not to change them... Guess what a couple months down the road one side of the engine lost all the retention springs around the valve seals into the motor... Were not sure how bad its hurt yet.

Since my financial situation has gotten better over the last year, I might buy the ol lt1 back and get it back to dialed again. Im thinkin ls1 pcm/coil swap, bigs/ skinnies, swap the dish pistons for a set of flat tops, new custom grind cam, and a set of 4;30's for the 9"