Vortec heads

[mtnrat]

I am tweaking my engine this winter and am looking at using the comp cams XR264HR-xtream marine and a full roller retrofit.
I have a lead on some New vortec heads with these specs.

-1.940"/1.500" Stainless High Flow Valves
-Hi Performance Springs Good To (.500 lift)
-PC seals
-Hardened Locks,Retainers and Seats
-5 Angle Valve Job
-CBN Finished Deck
-3/8" Studs
-Fully Machined For High Lift Up To .550" lift

Looks good for my application?

 

[Bondo]

Re: Vortec heads

I would Think so,.........For the Heads anyways...........

What's the Specs on your Cam,..??.....

 

[mtnrat]

Re: Vortec heads

something like this:

Camshaft Part # 12-408-8 Designation XR258HR-10
Duration @ 0.006" 258 / 264 Duration @ 0.050" 206 / 212
Max Lift w/ 1.5RR 480 / .487 Lobe Separation 110
Lobe ID#'s 3311 / 3312 Intake Centerline 106

Or this:
Camshaft Part # 12-412-8 Designation XR264HR-10
Duration @ 0.006" 264 / 270 Duration @ 0.050" 212 / 218
Max Lift w/ 1.5RR 487 / .495 Lobe Separation 110
Lobe ID#'s 3312 / 3313 Intake Centerline 106

or even this custom?

The cam was as follows:
Roller, masurements at .050"
lift .450" both
Inake Duration, 202*
Exhaust Duration, 212*
IVO: -8
IVC: 30
EVO: 32
EVC: 0
lobe centerline, 107.5*
intake centerline 109*

 

[Bondo]

Re: Vortec heads

I like the 1st 1 Best,.............

The LSA,.... Should be between 109*,+ 112*......

The 2nd 1 is getting towards the Ragged Edge of Possible reversion issues........
But it'll make Great Power,...... Top End anyways.....

 

[mtnrat]

Re: Vortec heads

This one is a little milder than the 1st.
Camshaft Part # 12-407-8 Designation XR252HR-10
Duration @ 0.006" 252 / 258 Duration @ 0.050" 200 / 206
Max Lift w/ 1.5RR 472 / .480 Lobe Separation 110
Lobe ID#'s 3310 / 3311 Intake Centerline 106

There is also the Xtreme Marine hydraulic roller

Part Number 12-416-8
Engine 1955-1998 Chevrolet
262ci-400ci
8cyl.
Grind Number CS XM 264HR-12
Description
Intake Exhaust
Valve Adjustment 0 0
Gross Valve Lift 0.488 0.495
Duration At 0.006 Tappet Lift 264 270
Valve Timing At 0.006
Open Close
Intake 22 62
Exhaust 69 21
These Specs Are For The Cam Installed At 110 Intake CL
Intake Exhaust
Duration At 0.05 212 218
Lobe Lift 0.325 0.33
Lobe Separation 112
Recommended Valve Springs 986-16

Which is very similar to the XR264HR-10 and is like you say getting close to the edge.
I am leaning toward something like the XR258HR-10 or XR252HR-10.

 

[John_S]

Re: Vortec heads

Mtnrat, I started looking at some roller cams. So far, I am not convinced it is worth switching from the flat hyd cam. Even though I have a '97 block, cost of cam, rollers, roller spider & fastners, pushrods, timing gear set, cam retainer & bolts, fuel pump push rod, and new timing cover pushes the cost above $700. Unless I find a frozen motor special, probably staying with current marine cam. Since I would only be looking at cams slighly more than stock, (+10-15hp), very little bang for the buck, compared to the vortec heads and going to a 4brl. The combined costs would have me looking for a fresh crate motor. Wondering if you found some tidbit I didn't.

 

[mtnrat]

Re: Vortec heads

JohnS, I just like wrenching and modifying stuff and have finished modifying my FZJ80 landcruiser. 6' lift, full armour, supercharged, regeared etc etc etc. I need to keep busy. For me working on toys is the single most relaxing thing I can do. I get huge satisfaction researching and building to create something that performs well when wanted and still has good manners. My landcruiser is my daily driver and tow vehicle and I go to Moab yearly to mtn bike and 4x4 as well as run trails such as the rubicon. It took a lot of fiddling to get it to the point that it drives smoothly at 80+ on the interstate wheels the rubicon and gets me 1100 miles back home with no problems. So out of my boat I want to have good manners, torque to pull skiers, and have a healthy top end. I think I can do that with an engine that puts out 300-325hp. I have a marine 350 that has only 20 hours so I am going to play with that.

 

[John_S]

Re: Vortec heads

I think I understand you, exactly d While I don't mess with cars anymore, the 350 definitly has some nostalga value for me. Had a '70 Nova SS w/350, back in the day.

Its kinda pathetic the 5.7L that came in my boat is only 210hp. Gees, brand new 4.3s have almost the same hp! Ok they don't have same grunt to get on plane. Anyway, I think mine will end up around 280hp. Should be plenty of power to go upto a 21 pitch prop and still perform well, all around. Should be still as reliable, too.

Speaking of mechanical pursuits and stuff, I imported a tractor, FEL, BH, from China a number of years ago. Had allot of fun assembling and learning about them. Even made a website: http://www.johnstractor.com Now, you can find those tractors for sale in about every state. OK, sorry, back to boats.