Aaron-74

I called compcams today in school..told them my combo and what I wanted. With my 3.70's and tires and given compression, head work etc..The STRONGLY sugested the XE-268 and said i'd be happier with it than the Magnum 270...I think I will be happier too. More lift...not a whole lot more duration.

Metal Wulf

good cam :thumbs:

GTR1999

Aaron did comp say to use the Xe268 with lower CR then 9.5? Just interested because that's what they told me last year.
Gary

Ryan77

I'm running the 268XE in my stock compression L48 and I like it. I'm sure it would be even better with more 9-9.5:1 compression. And Comp Cams does say to use the XE series cams with 9.5:1 or less, becuase they are more prone to causing detonation on anything higher than that. For 9.5:1+ they recommend the Magnum cams, as they do a better job of bleeding of cylinder pressure. Good Luck with the motor rebuild.

GTR1999

Thanks Ryan,that's what I thought I was told.
gary

Aaron-74

Yes. Well. They told me my 9.7:1 would be okay. I just have to make sure I run premium. They said I would like it a lot more than the XE-268 more than the Magnum 270 because the XE is a dual pattern cam and the extra beef on the exhuast is going to help my low-end power and torque more than a Magnum 270.

With my rockers the lift is going to be right at .508/.512 which is pretty good for a street motor.

Anyways..I'll keep everyone posted. The motor is going to machine shop tomorrow. They're going to aline hone the block, hot tank and magnaflux, deck it, install cam bearings, micro polish the cank, deck the heads, intsal the pistons and align hone the rods. :steering:

no_radio

Comp told me the same thing...'cept I am running aluminum heads and have a nearby airport for 100+ octane so I may put the XE268 in one of these days just for grins.

Jeff

Aaron-74

Yeah Jeff, but your compression is probably some where near 10.5-10.7:1. So you're going to need a high octane to run an XE-268 or XE-274.

Anyways, Since my compression will be a maximum of 9.7:1 I should be okay.

Crash Dummy

Jeff...

It' been awhile since I heard someone running aviation fuel. I used to have some friends in south Louisiana who mixed their own racing fuel with the aviation stuff. For those of you who have never been around a drag strip and racing gas(106-112 octane) it doesn't even burn your eyes from the fumes in an enclosed area and actually has a sweet smell to it.

Out of curiousity... I wonder what racing gas goes for now? Back in 1992 I was paying something like $5.75/gallon for 106 octane. And 5 gallons would make it a little over 4 burnouts and 4 quarter mile passes.

Aaron-74

I think Jeff said it's 20-30 more cents more than normal gas. But you have to know how many gallons you need ahead of time..or something. I think that's what Jeff said.

no_radio

At the local airport it's about $2.15 a gallon I think...been a month or so since I filled up, but need to get back over there as I'm on empty. I mixed it with 93 octane about 50/50. At this particular airport you have to pay by credit card, and have to select the $$$ you want before pumping, then pump yourself. Not a big deal...this time I will put about $ 20 in it, then go straight to Shell and top off with 93 octane.
Does smell nice, and keeps the detonation demons away!
My buddy Tom actually discovered this...his '67 Firebird pings like a bee-atch if he doesn't run 50/50.
Jeff

Aaron-74

Me you and tom need to get to sealy Jeff....

gdh

They recommended the 274 XE for my stroker last year (10.5:1)

no_radio

THat't the cam I was thinking of when I called them. They suggested no XE cams due to high cylinder pressure and risk of detonation. They recommended the 270H. Nice cam, but I have a 268H and am not going through all the trouble for such a small bump. When I install the electric fans I will consider some kind of cam swap, just not sure which. May try the XE274.

tersian

It smells nice to me to. Especially when I am flying! AvFuel is $2.20/gal at my airport, but it's a rural area. In the city they are getting $2.60 and up. I don't use it in the vette, but it works nicely in the Cessna.

To check where to get AVgas in your area, use http://www.airnav.com

Ryan77

There is a guy who goes to my local cruise-in every week and has Hemi Challenger R/T that he runs 100+ octane fuel in, within a few seconds of him going by you get that "sweet" smell :cheers:


[Modified by Ryan77, 8:20 PM 4/4/2003]

Jvette73

Thats a good choice. It will work much better with a 2500 stall. You'll see one you get it in. Try it with the stock convertor. Youll notice the sluggish bottom end. Then you'll want a looser vertor im sure.

Aaron-74

Yeah. I'm pretty sure of that. But I can't afford 300.00$ for one right now. It will have to wait until summer.

The motor is at the machine shop right now. It will be done wednesday.

gkull

Screw Comp Cams. With 9.7 you need something that would make more static pressure Like the Crane power Max 272. with 1.6's or it's even bigger brother the PM 278.


Many years ago i did my 355 ci just like a hot rod mag test motor. the 272 Crane made just about 376 hp with 9.5 The 278 made 412 In the test motor dyno sessions. I went bigger and used single plane and 10.7 CR with each of those cams with larger heads than the hot rod test motors. My best 1/4 time was 12.38 with 10 inch slicks

Sigforty

I have a bunch of friends that mix there own version of race fuel. Down here alot of us tend to use Xylene, Toluene and Benzene combined with 93 octane to make a better fuel. I do not think I know of anyone who uses aviation fuel to mix.