400 hp

iTrader: (19)

ok i bought some afr 1040 heads. and i have the gm hot cam now in my motor with 1.6 rr. so im thinking the comp xfi268 cam. is this a good cam to use or should i use somethink else.... dont want the cam to be to hard to tune..

JakeJr

What's your plan? How will the engine be used and what do you expect from the cam change.

The XFI268 is an excellent cam - received rave reviews from the Forums I visit - but whether it'll meet your expectations depends on what you're looking for.

Jake

400 hp

iTrader: (19)

ya it looks like a very good cam. my car is 80% street car 20% drag car looking to make 360-370 rwhp.. not sure that cam will do it. might have a custom grind done.. by comp cams...comp cams sent me a email they recomnend the 08-306-8 290h-r12 cam 230/244-510/540 112 2000-6000 rpm

JakeJr

WOE! They're recommending a 230/244 for a 355 CID engine that's to be used 80% on the street and with such a reasonable HP goal???

I looked it up and your setup meets the specs in Comp's catalog, except the 290 is intended for Street/Strip. My thinking your use is MORE Street than strip. It just seems too long in the duration department for a 355 at least for ME it is. It'll be roughly two sizes up in duration from the HotCam you're running now; you'll definitely be able to tell the difference.

You can expect a very noticeable idle; I don't know your views on that. That idle may be something you want, I know my 23 year old son does. Based on the specs, it's more oriented toward mid-range (3k-3.5k) and up power range in a 355 engine, even though the catalog says 2k-6k.

It's a great cam but only if it meets your expectations, a personal preference call. For me, I like to keep cam duration on the conservative side - meaning on the short side in the duration department.

In all the years I've changed cams, I was ALWAYS more satisfied with a cam on the short side of the duration spec. For a 350/355 I'd wouldn't go longer than 224/230 in order to keep the low end torque up and improve the idle. Being older (65 years last time I looked) factors into that. Again, a personal preference thing.

These are just my views, trying to keep in mind what YOU expect; YOUR goals. 80% street tells me to keep duration on the short end of the spectrum.

As an example, when I ordered a custom cam from Comp last summer for my son's 96 LT1, I deliberately kept duration on the short side for his 350 (214@ .050) to keep the bottom end response, but tightened the LSA to give him the idle he wanted.

Don't let what I prefer to interfere with what YOU prefer. I'm just trying to give you an over-view. Hope some of this helps you in your decision making.

Jake

400 hp

iTrader: (19)

ya that cam is to much i like the xfi268 but not the 113 lsa if was 112 lsa it would be good to go i will call comp cams.. thanks.

Damon

If it was me, I'd leave the cam alone for now and just do the head swap. I think you're in for a "holy cow" kind of improvement in the upper RPMs from the head swap alone. Unless those Vette heads are seriously worked I don't think they can hold a candle to the AFRs you're about to put on.

You can always do the cam later. The only thing you'd be doing twice would be R&R on the intake manifold and another valve adjustment.

Plus you'll get to see how much improvement from just the heads and then the improvement from the cam swap later.

400 hp

iTrader: (19)

my vette heads are worked over real good... i spent a lot on them to much... but i think your right the afr heads. should be a big improvement..and i relly want to buil a 383 motor. for next year..my hot cam is 525 lift. so i wont max the heads..

400 hp

iTrader: (19)

ok went with 268xfi cam.. next week i will do the top end over. heads and cam..

Burnout91

HSR, XFI268, AFR #1034 195 Eliminators (Chambers milled to 62cc), Dyno Don's
1-3/4" shorties.....

samiam91RS

who tuned the setup for you?

400 hp

iTrader: (19)

i tuned it myself

samiam91RS

I'm dreading that i may have to do mine as well.