So I am looking to redo my topend and need some help chosing the right parts that will match well. I want to use either the XFI 268 or the XFI 280 in a non roller. I want to bring back some of the low end I lost with the hsr swap. so I think the 268 will be a better choice for that. Now I need some heads and have 3 that I narrowed down from. I have a 350 bottom end and would like to be able to be around 400hp mark. I would like to use the blueprint heads for cost but if they don't flow enough ill step up.

http://www.summitracing.com/parts/tf...make/chevrolet
http://www.summitracing.com/parts/dr...make/chevrolet
http://www.summitracing.com/parts/ml...make/chevrolet

268 will have much more low end and midrange than the 280. The 280 is strong from 4000-6500. 268 should be strong from 3000-5800

Any of those heads would work well as long as you put in the right springs. The xfi stuff is hard on valvetrain components and requires a stiff double spring or good beehive. Most heads do not come out the box with these springs.

Also look at jegs brand 195's.

The blueprint heads say they come with duel springs. Would that be enough for the cam or should they still be upgraded?

Means little.
Need to know what max lift they are rated for ?

Find out the spring pressures at seat and open height or the spring rate. Generally the xfi stuff i would venture under 145 lbs seat and 375 lbs open. Most dual springs for lsx motors are near these specs so i would use them with correct retainers

right from the blueprint website. Do you think they will do? I will upgrade them if necessary. I am also going to use 1.6 rockers.

Max lift is .575

Springs

Valve Springs Included: Yes
Spring Pressure Open: 295-305 @ 1.225
Spring Pressure Closed: 115-125 @ 1.800
Outside Diameter of Outer Spring (in): 1.437 in.
Damper Spring Included: Yes
Number of Springs per Valve: Dual
Retainers Included: Yes
Retainer Material: Chromemoly Steel
Locks Included: Yes
Lock Style: 7 Degree

They will work to about 5300-5400 rpm with the xfi. Not stiff enough to see full rpm range of either 268 or 280 cams.

You want more like 135-150 seat and 350-400 open atleast

will these do? summit only had 2 sets with the 350 open. I am a novice when it comes to this stuff. I just want to make sure it all will work well together. Thanks..

http://www.summitracing.com/parts/hrs-98433/overview/

No need more open pressure.

Trickflow 1.460" springs can work for the 268 cam
http://www.summitracing.com/parts/tf...make/chevrolet
Alittle more money than other version you posted

Let me look up specs on the others

Jegs brand 195's with 1.44" springs are borderline for 268 xfi. Should support 5800-6000 shift but it likely will start to float by then.

Else back down to a xe grind or softer lobe.

Talk to pro-filer directly, they can likely setup the heads with a killer 1.26-1.29 diameter double that will like the xfi grinds

maybe a different cam suggestion that will go well with the heads and HSR. I am looking for lopey midrange power.