Vortec Head Modification/Upgrade

[aimlow]

I started a separate thread in the event it wasn't worth the effort........my apologies.
I did check the gasket vs the exhaust manifold..........the openings on the manifold match those on the gasket.
So it would be beneficial to match the exhaust ports of the head to the ports of the manifold?

No. The opening in the head being smaller than the manifold will HELP with anti-reversion of the exhaust. Keep the exhaust ports like they are.

 

[Bt Doctur]

Gasket matching is a lost art nowadays.You start and the carb`s base and the intake manifold matching the carb holes to the intake holes. Then you move on to the intake manifold runners matching the intake runners in the head. From there you match the exaust ports of the head to the manifold or headers your planning to use and making sure the gaskets are also modified to match. I would not be surprised if you found an extra 10-20 horses

 

[Scott Danforth]

for a marine head, make sure the top of the ports match the top of the manifolds.

I like to have the bottom of the ports about 3/32 higher on the heads than the manifolds. I like to blend everything back to the chambers on the exhaust side. I use 120 grit and 180 grit tootsie rolls

for the intake side, I use a carbide and leave it rough. I match everything on the intake side, leaving just about .020 from the gasket to allow for the gasket to move a bit during installation.

bowl blending and knocking off the casting dimples on the combustion side is about 5hp alone. if you want to really get anal, cc'ing the heads is good for about 5-6hp

 

[FreeBeeTony]

From there you match the exaust ports of the head to the manifold or headers your planning to use and making sure the gaskets are also modified to match. I would not be surprised if you found an extra 10-20 horses

WOW............that makes it sound like a worth while effort!
As you can see in the pics the matching is mainly on the bottom.
Guess I will also check the intake side for port matching.
Not going into any bowls............that's outa my wheelhouse!

 

[aimlow]

There's no serious power to be found on the exhaust side.,,too restrictive an exhaust. You also want to eliminate ANY possibility of exhaust reversion. 3 angle valve job, bowl porting, knocking off rough edges is worthwhile.

 

[FreeBeeTony]

Installed the heads today and adjusted the rockers.
See pics below. The one w/ the stamped rocker was the orig Vortec springs, the one w/ the blue roller rocker is w/ the new springs/rocker studs.........you can see the improvement......doesn't look close to binding.

Can't wait till spring!

 

[scoflaw]

Looks loose now. what's the seat/spring pressure valve open and closed ?

 

[FreeBeeTony]

See specs below.....these are the springs recommended by Comp Cams for the Cam I installed.

 

[scoflaw]

So if the install matches the spec. you be good to go. Good luck

 

[FreeBeeTony]

The installed height is actually 1.800"...........it's within specs.

 

[scoflaw]

I would think the valve open spec. would be more important. If there isn't enough pressure on the seat at high rpm's ,the valves will float.

 

[FreeBeeTony]

Both heads installed and valves adjusted. Installed Intake, dist and (1) exhaust manifold this w/e.......should be ready to start when the weather allows........no more freezing temps!

 

[Lou C]

Ahh winter is counting down...gonna be 50* on LI today....saw buds on the trees....went down to Robert Moses to get our 4x4 permits...you're almost there Tony....

 

[FreeBeeTony]

That pic looks like the Sore Thumb!

 

[Lou C]

It is! My favorite 4x4 place here. Lots of variety there...

 

[FreeBeeTony]

. Lots of variety there...

Not much Beach left though!

 

[Lou C]

True you have to be careful driving down there, between the crazy people letting their dogs and kids run all over. Much more beach at Democrat Point. I prefer going in the morning weekdays in the summer if I can. Really nice then. I'm doing a resto on our old '98 Jeep Grand Cherokee so we can use it more there this year. Adding a lift with OME (Old Man Emu) springs and shocks, 30" tires.

 

[FreeBeeTony]

We went there for 10+ years w/ 5-6 other families in the 90's through ~2008..........a lot of great memories, not much fishing, lots of BBQing and volleyball (not enough beach for that anymore). My kids grew-up on that beach, we used to bring play-pens they were so young.

 

[FreeBeeTony]

Well.........got the engine back together.
Yesterday seemed like the weather was OK....here's the 1st starts..........so far so good!
The clicking noise is the exhaust shutters.

 

[Lou C]

Looks great Tony! Good oil pressure and temp. On my OMC the flappers make a totally different noise being rubber coated fiberglass. Sounds like a knocking bearing and damn near drove me crazy till I figured it out with my mechanic's stethoscope.