[performerrpm]

anyone still running this cam, or has it pretty much been abandon?

i actually yanked out a xe274 from my 11.5 cr 455 just to use the 290b which at the time was the way to go...i didnt get there tho...everything got shelved for years...anyhows im there again with another motor but with the roller version xr276.

if the 290b6 is still available, which one wins?

455 block/428 crank/ 433 ci Icon forged pistons, will most likely use the 78cc speedmaster heads. should be just a smidge under 10.1 cr could go 72cc to get 10.5, either way im not so sure the xr276 will like the compression. not sure i got the cubes for the 290b. either was planning to use an rpm with 276hr but not 100 if thats the way to go on the 290b-6

[performerrpm]

btw....i have a 800cfm quadrajet in the sales section here, if it dont sale, with any luck at all i will run it....altho i may have to send it to cliff to make it happen.

[mysticmissle]

i have the xr276 in a 40 over 455 with iron ported 1970 #15s so about 9.8 to 1. i am running 1.5s it is a great combo on the street. i think with your added flow and compression, i would run 1.65s on yours, it would be a torque monster and still run on 93.

[performerrpm]

im glad to hear someones happy with this cam, makes me feel a lil better about putting it in now.

[mysticmissle]

I actually got the cam
From my buddy he went 11.6ish in a full
Bodied 3600poundish 5 speed 406 Kaufman d ports 389 gear 65 gto
He
Took it
Out for a couple
Sizes bigger and picked up a bit but he also had the heads taken out to 315-320
Or so

[Steve C.]

Setting aside performance obtained for a moment with this for conversation....

It seems odd comparing the specs of the XE276 hydraulic roller lobe and the 290b-6 flat tappet lobe. A big mismatch, one has 224 at .050" and the other has 255 at .050".

I don't have numbers for the XE276 Hyd roller lobe. However as an example, from their Spintron research the engineers at Comp Cams found their XE hyd roller lobe rated with 282 degrees seat duration and 230 @.050" under running conditions at .006" tappet lift had about 277 degrees duration. These numbers are based on a 1.5 rocker ratio and the loss follows right up the lift curve.

Under similar testing their XE solid flat tappet lobe with 236 at .050" with .016" lash under running had 274 degrees tappet duration. Noting here they added only 6 additional degrees of duration for the solid cam over the hydraulic cam.
It has been said mechanical cams usually need about 8-10 degrees more duration to have a comparable power band to a hydraulic lifter cam in the same engine.


.

[Steve C.]

From a post made by steve25 ......

"I have had the 290b go 10.80 in .030" over 455 with ported 260 cfm iron heads, 1.65 rockers, reworked T2 , 850 Carb , 12 to 1 comp , 4.11 gears in a early bird at near 3500 with driver." (shifting at 6200 rpm )

"The thing makes so much torque even with 11 to 1 in that size motor that even on the street with 3.55 gears I would find no drivability issues! "

Comp Cams 290B-6 Solid Flat Tappet Camshaft CCA-51-659-5
https://butlerperformance.com/i-2445...xC8L0gMQhm0aAI


( Information provided in this post does not represent any endorsement. And unless specified it is not based on personal experience and is offered for general interest only )


.

[performerrpm]

Originally Posted by Steve C.

Setting aside performance obtained for a moment with this for conversation....

It seems odd comparing the specs of the XE276 hydraulic roller lobe and the 290b-6 flat tappet lobe. A big mismatch, one has 224 at .050" and the other has 255 at .050".

I don't have numbers for the XE276 Hyd roller lobe. However as an example, from their Spintron research the engineers at Comp Cams found their XE hyd roller lobe rated with 282 degrees seat duration and 230 @.050" under running conditions at .006" tappet lift had about 277 degrees duration. These numbers are based on a 1.5 rocker ratio and the loss follows right up the lift curve.

Under similar testing their XE solid flat tappet lobe with 236 at .050" with .016" lash under running had 274 degrees tappet duration. Noting here they added only 6 additional degrees of duration for the solid cam over the hydraulic cam.
It has been said mechanical cams usually need about 8-10 degrees more duration to have a comparable power band to a hydraulic lifter cam in the same engine.


.

i wasnt really comparing specs of the 2 cams, just when i was debating if i had the right cam for the current motor for whatever reason the 290b came to mind. sounds like i might should give the xr276 a shot since i do have it already.

theres a couple youtube videos, one of a 65 gto at a burnout contest, he used to be a member here i think his name was phil or something...that car is pretty much what got the 290b stuck in my head. watched that video numerous times back in early 2000s.

[Steve C.]

Sorry for any misunderstanding. I was posing regarding the thread title "290 b6 vs xr276hr" and the comment "if the 290b6 is still available, which one wins?"


.

[performerrpm]

Originally Posted by Steve C.

Sorry for any misunderstanding. I was posing regarding the thread title "290 b6 vs xr276hr" and the comment "if the 290b6 is still available, which one wins?"


.

thats just my horrible typing skills lol


no i posted this actually in wrong section too, i thought i was in the street section an not the race but the 290b is racey cam so maybe the mods will be cool with it lol.what happens when you go reading post from 10 years ago at midnigbt lol.


anyhow, i was just seeing which one wins out as the one that woukd work best with the combo of parts i got.

in an

[PAUL K]

If set up properly the 290b would whale the crap out of that HR cam.

[performerrpm]

Originally Posted by PAUL K

If set up properly the 290b would whale the crap out of that HR cam.

at 9.9 cr and only 433 cu in' you think it would?

[performerrpm]

Originally Posted by PAUL K

If set up properly the 290b would whale the crap out of that HR cam.

and what intake would you say it needed?

[Jack Ferris]

One of my customers still runs the 290B in a 4.180x4.250 engine, a set of Dave's cnc Eheads, perf RPM and a 950. it will run 10.80's at 3700# at the 2000' tracks.

[PAUL K]

Originally Posted by performerrpm

and what intake would you say it needed?

Most likely a single plane

[performerrpm]

i think ill order the 290b if its available and set it to the side for my other block/eheads ive been kinda hoarding.

with the current state of resale value in pontiac parts, i maybee ahead just to finish this one with the hr.

[performerrpm]

i did end up getting a 290b6 -used- but in my ad Johnny 406 posted his cam card, which read the same as alot of pics on here or pisted specs, but on comps site, it reads a lil different. i robbed Johnnys image

[Steve C.]

Specs are slightly different than listed at Butler.....

https://butlerperformance.com/i-2445...eeZ2CO3m38w2gw



.

[jamaca85]

it looks like they used the 1.65 rocker specs on the lift on the cam card that was posted and not the 1.52

[performerrpm]

well that would take care of gross lift, but shoukdnt affect the duration at .050?
how can it be the same cam, same timing events, but at different lifts.....015 vs .020