I'm looking at the COMP xtreme fuel injected cam http://store.summitracing.com/partde...4&autoview=sku 216/223 @.50 .499"/.493", COMP says it uses beehive springs, which I dont have the money for and they also say they require machining to the heads which I really dont have the money for. So I was wondering if regular springs that are good to .550" will work? I dont see it beeing a problem but better safe than sorry. Thanks. James

 

Just use an appropriate spring. One that has the right open and closed pressure, and can handle the lift of the cam. Forget about the extra money they want from your pocket buying another one of their products.

 

stock springs will not handle .550 lift, if that's what your using...the springs are designed to work with those xfi cams...they have a new design that allows them to run less spring pressure without valve float (that's my understanding anyways)..but a reg. spring should work if you have correct installed height....also the xfi series cams require 1.6 rockers instead of 1.5's...trust me I went through all of this myself...I own an xfi cam now.

 

Doesnt matter what rockers you use, all that does is affect the lift at the valve. The specs he posted are with 1.5 rockers anyway.

 

I disagree....rocker arm ratio is very important...when it say .499/.493 lift, that is at the valve using a 1.6 rocker....check the link he has (or check with compcams.com)...as the bottom it says "Xtreme camshafts are engineered for 1.6 ratio rocker arms and beehive valve spring.." ALL of those Xtreme fuel cams use a 1.6 rocker ratio and are designed for such. If you use a 1.5 ratio on this cam the lift will be .468/.462

 

I guess Summit doesnt know what the factory ratio is then, which is where I looked. You didnt notice it either. Not surprised though, Summit makes mistakes a lot. Only thing I missed was the part about it being a flat tappet version, so its probably not the right cam for him anyway unless he's running an older block or wants to ditch his roller lifters.

I'm not aware of any factory SBC's running 1.6.

I already know about the XFI cams, I've been using one for 4 years now. You can run 1.6 rockers on a cam designed for 1.5 rockers so like I said it doesnt matter. The cam does not care what the rockers are, its a piece of steel with no brain. For some, it might be better to stick with 1.5's because their head or spring or both may not be able to handle that extra lift. The XFI line is about the most radical ramp profiles for off the shelf cams short of solid lifter racing cams that Comp sells, and they are very abusive to springs. Comp also sells a whole line of cams that came before these called Xtreme that have similar valve lift characteristics and open times, and people I know run 1.6 rockers all the time on those to get the extra lift because they want it. Those also got a lot of complaints about valve springs because of ramp speeds so using a 1.5 instead of 1.6 is only going to help for those that dont want to run a really crazy spring. But the rockers are a secondary issue to the cam, you run whatever rockers you choose to. Nothing in the cam requires a specific rocker.

 

okay I missed the part about it say "intake with factory rocker arm" so I'm mistaken according to that web page, it's a misprint in summit web page. I called comp cams....it is the same lift number using a 1.6...so I still could be correct..the lift would be smaller using a 1.5:1 rocker.....also there are no small blocks running factory 1.6's I was just saying the cam is designed for a 1.6 rocker.. they said that the cam will work with 1.5 but is actually specifically designed for 1.6 ratio, and it decreases the advertised lift....here is the link for the same came grind number but in a roller...I agree it should be a roller...so did comp cams...
http://www.compcams.com/Cam_Specs/Ca...?csid=207&sb=0
and yes I have too much time on my hands..bored at work here.

 

1-800-999-0853 if you don't believe me.....

 

Yes, I am running an older flat tappet block and dont have the $300 for the retro-fit cam, then another $400+ for the retro-fit lifters. I already have a set of springs, and like I stated before they are good to 550". I also already have a set of 1.6 rollers laying around to. Just wanted to make absolute sure they didnt require the $300 valve springs.

 

Not as long as the seat and open pressure are ok. Any idea what they are?
I'd make sure once its mocked up you actually have some clearance from max lift to coil bind, doesnt always work that way when things are assembled and various factors fall into place.

 

I dont remember off the top of my head, I'm still tossing around this cam and the cam I already have depending on which heads I choose. But I'm really liking how those XFI cams look. One other question, in the application section it says 87-98, but its a flat tappet cam so it should still work, correct?

 

It should. Might want to check Comp's website and info since Summit still doesnt understand the specs on the XFI cams. Who knows what else they have wrong.

I looked anyway
Comp says:
Chevrolet 262-400 c.i. 8 cyl. 1955-1998

Strike two for Summit.

 

Ok thanks, I always forget summit is horrible with there info.

 

I never usually go off summits info...they have so many parts to list I think they mess up often......I didn't know you needed a flat tappet...but looks like you have it figured out, that motor should run out good when your done.....