Why do the XFI grinds how much higher lift numbers than their other cams? Are these for cars with ported heads? I notice that the XE (500, 502 etc.) have lift around .500 and say they are best for stock lt1. Would there be much benefit with putting an XFI cam in my car that has more lift than an XE with the same specs but less lift?

Is there much of a benefit with going over .500 lift in a stock headed lt1?

 

Yes, there is always a benefit of going with more lift even if the heads do not flow more. Valve lift is not a function of flow, it's a function of area.

Bret

 

I believe the difference you are referring to is because the XFI cams are advertised with lift numbers using 1.6 rockers, as that's what they're meant to be used with, while most other cams advertise lift with the stock 1.5.

 

I’m getting ready to install a 396 LT stroker, w/ AFR 195 LT4 heads and 12.1-1 compression in my 97, Z28 which is primarily a bracket car and only driven on the street occasionally (emissions are not an issue). So, now I’m looking for the “best cam” for my application (2200-6200 RPM range w/ 3200 stall and 3.73s) and was looking over the newer Comp XFI 292/300 deg, .584/.579 lift (the largest XFI cam for the LT w/ 1.6s), as opposed to the older Comp 306. And, wanted to get some opinions here on the forum about the XFI cam. Basically, how many people are running the XFI cam in a stroker and how well it performs! Also, the comparison to the Comp 306 performance, or other LT cams.

 

I was looking at that cam too for my 396 before I decided to go solid roller. I'll bet it would be a killer cam.

 

for an off the shelf cam ...the 468 will work fine in your application

 

My suggestion on this is run Comp Cams 3100 Lobe Similiar to the XFI Lobes but more aggresive. They also have more Lift per degree of duration, ex Small duration and high lift. For springs I would check out the new Single Beehive 986 Spring that comp just came out with and it can hadle .650 Lift andhas a 1.412 O.D.

 

I really am happy with my xif cam. Its only in a 355 but makes really good power. Its the 236-242 at 580-585 lift 1.6 rockers on 111 lsa

 

I can attest that nonosvt's car runs well, he was the 1st person I know with a XFI grind.

 

I'll be using the 280XFI with 1.65rr (230/236 .596/.591 113 LSA) in my 350 with 10.6:1 CR. When I have results I'll let you know.

 

Ben,

The 986-16 aren't beehives and they aren't new. They also are not enough spring for a hyd roller if you want to do anything with it.


With your 396, you need to make sure you balance out the 12:1 compression with the rest of your specs and RPM range of the motor. 6200rpm is not very much RPM, but you still need to be aware of how much curtian area a stroker needs to feed the motor enough air up to that RPM. The XFI lobes are nice lobes but you might need something larger just to deal with the cubes.

The 3200stall basically makes your minimum RPM in terms of WOT performance but by the sounds of it you also want the car to be driveable below that down 2200rpm. That means the part throttle characteristics of the cam/motor have to be what you are looking for as well.

Bret

 

Something I forgot to mention with the Comp XFI cam. And that is the rod bolt, cam lobe clearance issue with a 396 stroker. This could be a problem with a 396 stroker and it would be a real PITA to buy the cam, install it then discover the rod bolt clearance issue and have to start over looking for another cam.

http://www.cardomain.com/ride/2189634

 

Can you go into more detail? I have a 383 (3.75" stroke with 5.7" rods) and I plan on using an XFI cam. Any issues you can see?

 

Brett I think T/A kid was refering to the 26986-16 spring....

 

With the 396 stroker and possibly the 383 as well, rod bolt clearance with the cam lobes can be an issue. To overcome this problem (as I understand), cam lobes are ground on a small base lobe circle to provide the necessary clearance with the rod bolts. The cam will have the exact same duration and lift, but on a smaller base lobe. With an LT stroker, or any SBC stroker this always needs to be checked. I've been taking with Comp Cams today and they can custon grind the PN 07-468-8 XFI cam with a small base lobe circle and hopefully it will clear the rod bolts in the 396.

http://www.cardomain.com/ride/2189634