[mrmark1957]

I have a Comp XE256 cam and lifters that I am thinking of putting in a '73 low compression 400 (6X-8 heads). Car is a 73 LeMans, stock turbo 400 trans and 3.23 rear gears. Has anybody used this cam in a 400 like this.

[25stevem]

This Cam duration wise at .050" is similar to a factory 068 Cam, but with more lift.

Because of lack of compression the factory stopped using the 068 Cam once compression ratios dropped below 8.5 as is the case with your motor with the dash 8 heads.

[Stan Weiss]

I have not run this cam. But while it looks to have around the same 0.050" duration as a 068 it also looks to have less seat-to seat duration which should help it with your 8.0:1 CR. What LSA is your cam?

Stan

[mrmark1957]

The XE256 has a 110* lobe center, and short seat timing at 256/262 degrees. I found some old threads where they were used in 350 motors. I was wondering if anyone had put one in an 8 to 1 compression 400. Thanks.

[Skip Fix]

I used a XE 262 in one(low CR 400) that worked fine mild idle.

[nytrainer]

If you want to go a step bigger I have a Comp Cam XE 262 for sale here

[Stan Weiss]

Originally Posted by mrmark1957

The XE256 has a 110* lobe center, and short seat timing at 256/262 degrees. I found some old threads where they were used in 350 motors. I was wondering if anyone had put one in an 8 to 1 compression 400. Thanks.

Like I said in my other post I have not run this cam.

What are looking for out of this 400? While I see it making good mid range torque, but I see it making peak HP at a lower RPM than a 068 cam.

Stan

[mrmark1957]

I use the car daily driver/ street use, it's got working A/C. I just dont want to put another 066 in it if this one I have will work. I'm not concerned about power over 4500 RPM

[mrmark1957]

I use the car daily driver/ street use, it's got working A/C. I just dont want to put another 066 in it if this one I have will work. i'm not concerned about power above 4500 RPM.

[b-man]

212/218 @ .050 isn’t too bad on the cam you have available but if I had to put up with a low compression 400 as my daily with A/C I’d much prefer something like the Summit 2800 with 204/214 @ .050.

Don’t use a cam that might be okay and might not, it’s the heart of your engine.

I ran the 2800 cam in a 400 with 6X-4 heads with around 8.2:1 and it was a great cam, the car was a 1969 GP with factory A/C, a TH400 and 3.23 gears.

[Skip Fix]

Different low CR 400 in the 81 now has the Summit 2801 a mild cam also. 3.08s A/C etc.

[geeteeohguy]

The XE cams seem to work well with lower compression. Helped build a 389 with 8-8.5 CR ten or 12 years ago with an XE268 cam and it'll rip your head off, and do it with 89 octane fuel, too.

[mrmark1957]

I'm looking to get a little more power out of the engine and keep the idle smooth.I had this cam in a 9.5 to 1 455 and it idled dead smooth and was done by 3500/4000 rpm.

[Cliff R]

That cam is going to be a "turd" in a 400 build at any compression ratio....IMHO

I've had quite a few Pontiac 400's, and a few Olds 400's brought in here for "custom tuning" using the larger XE262 cam in them. A stock 067 cam would do better, at least from my basic impressions of how those 400 Pontiac engines ran. They idled OK, deep/heavy sound, thru a little power at you then fizzled away past 4500rpm's or so.

Not enough seat timing and those "fast ramps" work against you with 30 degree intake seats as they thrive on low lift flow numbers, longer duration, and wider LSA.

The best cam I've found for low compression 400's is the Crower 60240, it's 270/276 seat timing, 210/222 @ .050" and 112 LSA. Runs best with the ICL around 108-109 degrees.......

[78w72]

Originally Posted by geeteeohguy

The XE cams seem to work well with lower compression. Helped build a 389 with 8-8.5 CR ten or 12 years ago with an XE268 cam and it'll rip your head off, and do it with 89 octane fuel, too.

i have the xe268 in a W72 406, 6x-4 heads shaved a little, trw pistons, probably 8.75ish comp, 3.42 gears. its runs very good in all areas, smooth idle but has a nice lope, pulls hard to ~5000 rpm, never really pushed it further, zero detonation, no issues after 12+ years. car runs upper mid 13s at 103mph, taking it easy on launch (first time with a manual at the track) with old hard BFG radial t/a tires. it also runs fine on 89 or even 87 on occasion.

i dont have any other cam to compare it to & im sure there might be a "better" cam but in my experience i dont see what all the xe bashing over the years is about on low compression engines, they seem to run great from majority of user reviews & butler has pushed the xe cams in FT or hyd for a long time. mid 13's @ 103mph is pretty decent for a mostly stock engine.

being the OP doesnt care about power over 4500 it doesnt really matter if the cam is a turd above that rpm if it runs good for his low rpm street cruising with the a/c on.

[Stan Weiss]

Originally Posted by 78w72

i have the xe268 in a W72 406, 6x-4 heads shaved a little, trw pistons, probably 8.75ish comp, 3.42 gears. its runs very good in all areas, smooth idle but has a nice lope, pulls hard to ~5000 rpm, never really pushed it further, zero detonation, no issues after 12+ years. car runs upper mid 13s at 103mph, taking it easy on launch (first time with a manual at the track) with old hard BFG radial t/a tires. it also runs fine on 89 or even 87 on occasion.

i dont have any other cam to compare it to & im sure there might be a "better" cam but in my experience i dont see what all the xe bashing over the years is about on low compression engines, they seem to run great from majority of user reviews & butler has pushed the xe cams in FT or hyd for a long time. mid 13's @ 103mph is pretty decent for a mostly stock engine.

being the OP doesnt care about power over 4500 it doesnt really matter if the cam is a turd above that rpm if it runs good for his low rpm street cruising with the a/c on.

I agree 100%.

Stan

[Cliff R]

A reality check is in order here. The OP is asking about the tiny XE256 here, not the larger ones. The XE268, and XE274 start to have enough seat timing in a 400 build to make decent power. The XE256 camshaft isn't big enough for a 350 build at 8 to 1 compression IMHO. It will still probably make enough power to do a decent burnout in a hard right hand turn leaving Dairy Queen, so all is well in the big scheme of things.......

[Stan Weiss]

Note I have not run this cam and so this is a JMO.

The XE256 in a 400 ci engine even installed on a 110 ICL will have about 155 PSI cranking compression. IMHO I see the XE256 making more lower RPM and peak torque (at a lower RPM) than a 066 cam.

Where the short seat_to_seat duration will play out is in where the engine makes peak HP and is done pulling, IMHO around 4300 RPM.

Stan

[Skip Fix]

I agree with Cliff . I did run an XE 262 in my original 78 180 HP 400-I think specs are below 8:1. It was very mild -a step smaller will make less power and be done even sooner.

[Steve C.]

" The OP is asking about the tiny XE256"
"That cam is going to be a "turd" in a 400 build at any compression ratio"

My old Comp book states that cam has 212 degrees on the intake. My Crower book says the 60240 is even smaller... MORE tiny at 210 degrees on the intake.

Both are tiny. Won't both be turds !

.