I tried looking some things up but I couldn't find anything on the topic, only people who where trying 1.8 RRs with cams. I was wondering if the lift would clear with a full flowing exhaust and intake with a stock cam or if it would hi-five the piston. I would also like to know some problems I would have trying to implement 1.8 RRs (besides valve cover clearance, pushrods, plates, and springs). I don't plan on going internal and putting in a cam in my LT1 so I'm trying to find different alternatives.Any tips, or suggestions on making this work could be helpful. I have done my research on 1.6 RR and 1.7 RR and would just like to have all of my options layed out before me before I make my choice.

 

Well in my opinion the 1.8's are way over board for stock block/cam....dont even think ( i ) have heard have ppl having 1.8's..1.6's are perfect!

 

bad option, don't do 1.7's either

 

Any reason why I shouldn't go with 1.7s?

 

bad geometry, heavy

 

i say just go with the 1.6's and call it a day!

 

good call

 

Sorry if I'm not totally convinced by your argument. Can anyone else can tell me why I shouldn't go with 1.7 or 1.8 RR?

 

I saw some pretty good reasons. What about your springs? I did not do the math but something to consider. If springs do need to be replaced then why not consider some 1.6 and a cam?

Maybe install the 1.8 on stock springs and cam and give some 2k mile feed back.

 

Stock LT1 heads stall above 0.500" gross lift. They may actually flow less at higher lifts.

http://www.malcams.com/legacy/misc/headflow.htm

 

There have been tons of people with 1.7rr on stock cams. Both of the ones I can recall with 1.8rr I think were aftermarket cams.


Even with 1.8 the lift/duration with the stock cam is nowhere near where you have to worry about p-v clearance.


That pretty much covers it.

 

My 1.7s have been performing great since the install over a year ago. The dyno had me at 285rwhp SAE after the install as well (this was before my headers and tune).

I documented the 1.7 research and install here.

One problem I had was the pushrod bottoming out on the guideplate. I had to open the guideplate up more due to the added angle. One concern I would have on the 1.8s, is if the stock casting is wide enough to accomidate the angle of the pushrod.

Thomas.

 

Higher ratio rockers, while providing signifcantly more lift, serve to increase the duration very little---it's basically a poor man's cam. There is no doubt that increasing the lift and duration can provide rewarded increases in power, however, just like a cam, there is a point at which the gains are outweighed by the possible problems, and in some cases one may experience net losses.

If you are not convinced by others reported experience, then the only alternative is to go ahead and do it and let us kow how it works out. There are engines out there with up to 2.0 ratios (I think that ford's come out of the box with 1.6s and the LS are higher also) I would check with a cam guru and ask their opinion based on the profile of a cam that would match the numbers of the stock cam with the lift and duration of adding the 1.8s or 7s. JMHO

 

if it's a duration problem couldn't I get a custom cam that keeps the same lift as the stock but gives me a longer duration?

I haven't seen anyone trying to put 1.8 RR's in a car with a stock cam, so there isn't others with reported experience. The reason I want bigger RR's is because I don't want to go internal with my motor. At this point I want to know if I'll have problems with the cylinder head hitting the valves.

 

if your going to get a custom grind cam then why even ask about a 1.8 ration rocker?

This is a bad choice in my opinion, for what its worth

I also think a 1.7 is a bad idea....to change the ratio you know where the extra weight goes right? I feel it is just a sloppy way of doing something, just get you some regular rockers and a cam....

If you just want to do it to prove it can be done go for it. If I was you I would do more searching and alot more reading, I have broken lots of stuff and wasted lots of money over the years because I was misinformed or under educated...so do your homework, I'm just trying to help you out