What do you guys suggest for a stock LT1? Will I need new springs? What kind of horsepower gains should I see?

Thanks!

 

Comp Cams Pro Magnum 1.6 ratio rockers.

You can either get Comp Cams springs or LT4 valve springs.

Yes you need them.

17hp at 5700rpm or 22hp at 6100rpm if you raise your redline.

 

ga ga gooo!!! I have to get mine on soon!!!

For the record for the original poster, I have these Crane Gold SA 1.6s that i purchased from this board to install on my relatively stock LT1 - and I was told they were a good match for what you're looking for.

I was also told LT4 spring kit would also be a good idea as well.

Gripenfelter: is there a chance of damage by raising the reline to that level you specified?

 

6100 is fine for stock.

In fact some guys spin their stock bottom ends to 6600 rpm with no problems.

I spin my 383 to 7200 rpm.

 

I'll have to throw in a nod for Scorpions as well. I talked to several head porters and more than one told me they were surprised at the very high build quality of the Scorpions when they disassembled them.

Just because they're a little less $$$, don't think that's a bad thing. They are less known than Comp and Crane, so I think they're a really good deal right now as they try to build their brand name. I'm 100% happy with mine.

 

>I had Crane Cams 1.6 roller rockers 3/8 stud on my 94 (stock) now I run Comp Cams Pro Magnum 1.6 roller rockers 7/16 stud for my 396 supercharged engine .
The problem with the Comp Cams is valve cover clearance , but the Crane Cams had absolutly no problems .

BTW - I use AFR #1031 heads

 

Thanks for the input guys. As far as the comp cams rockers go, are the magnums close to the pro magnums in performance? They are cheaper, so I'd go with those if they are comparable in performance. Also, what about Vortec 1.6 rockers. Are they any good?

 

Scorpion also makes a 1.7 RR that will fit on our cars as well. You will need to use guideplates and new springs with them I believe, but will net you a few more RWHP than the 1.6 RR's.

 

You will need to have the whole geometry of the valvetrain scoped out if you do 1.7's. With any kind of higher lift cam, you could have some issues with the heads. For sure you would need to have that checked out and make sure everybody dealing with your valvetrain knows about 1.7's if you do that. If you don't you might still be OK........or maybe not. Hard way to find out.

For instance, lets say you had a medium aggressive cam with .355 lift at the cam lobes. A more aggressive cam would have even more lift than that, obviously. It's pretty simple math. With .355 at the lobe, you get:

1.5:1 RR = .533 valve lift

1.6:1 RR = .568 valve lift

1.7:1 RR = .604 valve lift


That's a big difference from stock rockers and not all heads are happy, or even flow best, at .600 and higher. Lifters get more stress. Valve velocity goes up. Piston clearance goes down. Some valvetrains won't live long at that lift, just depending on the particulars.

If you will never have a high lift cam and are staying stock or pretty mild, I don't think you'll have trouble, unless your stock lifters give out. I'm just saying, make sure 1.7s are a good idea on your setup, and will be compatible with future mod plans, before you go there.

 

1.7 RR are fine with the stock cam. Of course, a general rule of thumb with hydralic lifters is that you don't want to exceed .600 of lift, but on a stock setup, you will just be putting .506/.520 int/exh. Which is under a hotcam in lift. There is a guy on our local KY F-body board who went from 1.6RR to 1.7RR with a hotcammed C4, just had to use guideplates, and made an addl. 17-18 RWHP.

There are a few people on here using 1.7 RR with their otherwise bolt-on cars also. Do a search, but I believe you just have to use guideplates and upgraded springs with them, I think stock pushrods will be fine, no problem with head clearance.

 

Is this a good mod to do even if you've still got stock exhaust manifolds? Or is it better to do this mod after getting headers?

 

Guys, will I need new spring retainers and locks for my setup? I just got a great deal on LT4 valve springs off of eBay, now I need to decide on the Rocker Arms. I'd rather not get comp cams pro magnums if I'll need to modify the valve covers.

Thanks again!

 

GM makes retainers (GM p/n 12495492) and locks (12495503) that are specific to LT4 springs. That's what I used. You will also need guideplates (14011051).
Any aftermarket rockers besides the narrow body Cranes http://www.thunderracing.com/catalog...vid=4&pcid=108 or narrow body Comp aluminums http://www.compcams.com/Technical/Cu...ML/314-317.asp will require modification to the valve cover bolt tube supports.
Other rockers cost less but Pro Magnums are the best IMO.

 

Will any 1.6 small block chevy rocker arms work on the LT1? I looked at some crane cams rockers, but it didn't specify if they would work on LT1 or not.

 

For stock heads you need self-aligning, if you want to run non-self-alinging then you need to do guideplates. I believe all 1.7s are non-SA, and you might need custom length push rods with them as well. Not saying it is a bad idea just you can't buy a set and expect it tobe a 2 hour swap.