Porting Vortecs???

[88bluestar]

Have a set of 062 vortecs, keeping the 1.94/1.50 valves, need info on how much porting to do, and what not to mess with. Here's my combo, not with an ideal cam but it's what I have until I can get a much better engine put together.

750 Holley with 850 base, 1" spacer allowed.....I have an open one and 4 hole one to use if needed. 70/30 mix of 91 octane and 110 race fuel.
2716 Edelbrock intake, porting not allowed
elgin pro stock 1133 cam, 246/246 .050 106/110 -108/advance 4 degrees. 1.5 rockers
.040 2256L forged sealed power piston 5/64. 5/64. 3/16 rings
5.7 stock rod, arp bolts. 10/10 cast crank 3.480 stroke
dirt oval, 1/4-3/8 , on american racer kk704 tires.
.025 below the deck, likely running .039 stock head gasket with a roughly 67-68cc head chamber. 9.3-9.4 comp,
3000-6800 range, with a 7000 limiter

[zums]

Most of your porting work will be negated by that unported intake
Tom

[David Vizard]

Go to this thread :- High convenience low buck 383 Chevy truck motor.

There are pages on porting Vortecs with results and graphs.
DV

[Carnut1]

https://www.speed-talk.com/forum/viewtopic.php?f=1&t=49797 link address DV wrote of.

[RCJ]

We raced in a class with very similar engine rules.What I found was installing a 1.6 exhaust valve and opening it up to 88% .Then we didn't do any thing to the intake, gave the most bang for the buck.I also angle milled them .120 and used a .040 cometic with zero deck.Had to recut all the valve pockets.

[randy331]

Have a set of 062 vortecs, keeping the 1.94/1.50 valves, need info on how much porting to do, and what not to mess with.

Do you have a flow bench, or are you looking for ways to help the ports without the use of a bench ?

Randy

[88bluestar]

No flow bench. Stuck with 194/150 valves. Honestly the heads already have a 5 angle job, and I gather the intake ports are well enough alone, albeit I'd like to squeeze what I can out of this tiny turnip what I can. Sounds like I may look at the exhaust and just do a light burr and sand rolls to it, just hesitant since the valve job has already been done.

[F-BIRD'88]

A light polish of the vortec intake ports and or even just a "pocket port" effort will net you
0 result. No gain. But they will look pretty.
You will not get a real gain until you fully port the intake port
and then really only if you also increase the intake valve size too.

Leave the vortec intake port as is, as cast with the 1.94 valve.
(you, yourself are more likely to make it worse overall and make LESS power)
The exhaust side will respond to typical hand porting and streamlining the valve guide boss.
Do not make the ex port exit huge. all this does is create a leaky header gasket.

With that cam compression is your friend. You can mill the heads a bit and use a thin head gasket (.015") Use high octane gas if you do that.
Move that 246 deg cam to a 102deg 103deg intake C/L.

These heads make great power. pay attention to the guide guide boss/seal clearance with high lift. The pressed in rocker studs are fine for what you are doing.
Use a vortec intake manifold not a cobbled up shoe maker 55-95 intake pattern old manifold.

[F-BIRD'88]

Nice Isky oval cam for this. No machining req
isky 201278.

[tt 383]

Here is a thread I followed a few years ago...
http://www.speedtalk.com/forum/viewtopi ... =1&t=20012

[user-612937456]

I did one very similar a few years ago. Here is a cam that I got from Mike Jones Torque came on above 2500 and pulled to 7000 over flat all the way up with over 400 ft lbs the whole range average ft lbs 414 for the whole pull. (Flat Hydraulic)

Cam# SBCH, H71330-72334-108
228/232 @ .050"
.330"/.334" Lobe Lift
.528"/.501" Valve Lift w/1.6Int and 1.5Exh rockers
108 LSA"

The valves will limit your peak power numbers but pocket porting and cleaning up the exhaust can't hurt probably will helt a little at over .450 .

BTW all 5 angle valve jobs are not equal.

[user-17438]

A light polish of the vortec intake ports and or even just a "pocket port" effort will net you
0 result. No gain. But they will look pretty.
You will not get a real gain until you fully port the intake port
and then really only if you also increase the intake valve size too.

Leave the vortec intake port as is, as cast with the 1.94 valve.
(you, yourself are more likely to make it worse overall and make LESS power)

out of the dozens of sets I have done, yes you can improve them a ton, and I thin if you are putting an oversized valve in just a 2.00" is plenty big.
you can get some big numbers out of the 1.94 valve.

for a beginner, set the throat, blend it into the existing bowl and blend into the short turn. next you can thin the guide boss. that right there can net you some big flow increase.

just don't lay back the short turn too much. you can ruin the heads for what you are after if you get too aggressive there.

I will disagree that they need to be fully ported to see any gain.
you could always find a COMPETENT porter that will charge you minimally to do this work, port a runner for you so you can copy.

good luck

[Carnut1]

I need to know how someone can pick a competent porter from a hack?

[tt 383]

For starters ask them to add 2+2...

[user-17438]

I need to know how someone can pick a competent porter from a hack?

Simple one would be ask the local dyno operators or drag racers.
If the guy says ill gasket match it to a 1205 and use a 30 45 60 run away..
Ask to look at some of their work. If they make a straight line or looks like someone with parkinsons was drawing an oval or rectangle.. Run away no offense to parkinsons victims here.
Listen for key words like i will shape it or give it adequate cross section for your goal you are in.. Tell them what you want to do. If they want cam specs, compression, cubic inch, intake manifold choice, converter.. Chances are the person wants to sell you the right job.
If they just spew out.. Well i can get them to flow xxx cfm.. Run away..

Bottom line is it is hard to find someone competent, but there are always a few in each state that are really good.. No sense in sending a head 5 statesaway, when someone nearby can do the same quality work or better. I could go on for days.. But in the end a happy customer is more important to a local guy. Start local and look from there. You may be surprised.