Danspeed1

iTrader: (1)

I have a GTO with an LS1 that needs some pushrods. I decided to do a few upgrades over the winter. I purchased a torquer V4 cam, dual springs, all the gaskets for the top end, new timing chain and morel lifters. I also picked up a set of 799 heads from a van cheap. It has the stock 241s currently. There aren't really any issues with the heads, they came off a running motor. My plan was to literally clean them up, swap springs, replace head gaskets, and install them with the rest of the parts I picked up. Then it snowed... and I am not able to get the car into the garage at the moment. So I am trying to decide if I should attempt a home port job. Here's the deal, I've rebuilt quite a few engines but I've never ported a set of heads. My goal isn't huge gains or any of that. Just trying to repair the car, make it sound a little better, make it make a little more power. Its shaping up to be a long winter and its only December. I want to attempt this to see how it goes, and to learn. My goal is not to ruin the heads... and by ruin I mean make them unusable. If the gains or slim or at the end of the day, nonexistent I can life with that. With that said, is this something worth attempting at home, or should I just clean everything up and install when the snow melts?

SoCalDave

If you have the tools go for it and port your 799 heads. I went from the stock 241 heads on my '01 Camaro to a set of 243 heads that I ported both the intake and exhaust for as much flow as I can get. It's worth the time if you have it.

Danspeed1

iTrader: (1)

yea lol, I have a lot of time at the moment.

SoCalDave

Then go for it! Here is the exhaust on a set of 243s I'm working for a C5. This should give you an idea of what to do.

Kfxguy

iTrader: (1)

I have an 04 gto also, I ported my own 243 heads. However, I have ported many heads and have access to a flow bench. The way i got started was picking up a couple head porting books. You can now get them online. The original book written by David Vizard is a very good book to have and read. A couple times. I got over 300cfm at .600 lift with stock valves in mine. i picked up like 3-4cfm with ferrea valves. It was like 230 on the exhaust. It took three trips to the flow bench to get it there.
Theres also another book named (iirc) how to port CHEVY SMALL BLOCK CYLINDER HEADS, it honestly wasnt near as good as the DV book tho, but it had some decent info.

SoCalDave

I got a book by David Vizard and also found videos on Youtube. I used the tracks at Irwindale and Fontana to get an idea if my port work helped. I feel the exhaust work makes a huge difference over stock.

LaBLKv6Z

iTrader: (13)

HeadFlowInc on youtube has some great informative vids on the cathedral and rectangle port heads. I used him as reference when porting my 821's.

RB04Av

I usually find that the biggest gains in home porting, are from cleaning up all the steps and angles and whatnot right behind the valve seat, where the factory just jammed their cutter down in there; cleaning up any casting irregularities in that same area; and lightly forming the guides to a "teardrop" or "airfoil" kind of shape. Rounding over and smoothing the "short side" radius on the exhaust, WITHOUT lowering the port floor. Remove as little metal as possible overall. The object of the exercise being to encourage streamlined laminar flow, not turbulence and eddies.

Doing much of anything farther away from the valve has far less overall effect.

This should always be accompanied by a good quality multi-angle valve job, both on the castings, and on the valves. Significant gains in that alone, as compared to a lesser job.

Kfxguy

iTrader: (1)

You have it nailed.

Danspeed1

iTrader: (1)

I've been watching a lot of you tube videos and reading online. Thank you for all the positive encouragement, many of the threads I was reading had a lot of negativity. I think it pretty much goes without saying that, unless you are a professional with a flow bench your results are going to be mediocre; the reality being there really isn't anyway to quantify the work. I am very friendly with my local machine shop, they are really good guys. They have done a lot of work for my family over the years and are very encouraging. I wont waste their time with questions out of respect for their business, but when I bring the heads in for a resurface they will surely explain or repair any of the mistakes I may have made. I am fairly good with a grinder with other fabrication work so I will give this a try and see how it goes.

As mentioned, my expectations are low, I really don't even have any way to quantify my results. We know 243/799 heads are already decent, I was just trying to figure out if it was worth the time realistically.

Thanks!

Utinator

You could practice on the 241 heads first. I recently picked up a set of 706 heads that I don't need. My plan was to practice porting on them. I got them cheap, so I'm not worried about ruining them. I have been busy fishing lately, so I haven't had time to mess around with them. It might be a summer project for me.

SoCalDave

Another name apart from David Vizard is Joe Mondello. Read their stuff to understand the reasons behind port work/modification.

Danspeed1

iTrader: (1)

I wish I could but they are on the car, and we just got 2 feet of snow so, the car isn't going to be making its way into the garage anytime soon.

guessohw

If you can, get your hands on a set of cheap heads or a head and perfect your skills on there. I highly highly highly suggest making sure you have the longer bits to make it a lot easier to get way inside there. I know I see a lot of people also talk about making sure to get the thicker shank bits because the thinner are naturally weaker and or can break etc. Then some people have good luck with them so you know how that goes. But I’m looking to do the same thing myself so well way to find out and just do it! Good luck

Danspeed1

iTrader: (1)

I have been looking at the cost of entry and it doesn't seem horrible. Eastwood sells a nice sanding roll set for like $35 and there are plenty of misc Carbide bits available on flebay. As always I am sure that the right tools make all the difference but Im not looking to make this a business so I think the one time use stuff will work just fine.

Woodylyf767

I believe the David Vizard book talked about being able to quantify flow numbers with a DIY bench. It's really only good for comparisons of other heads on the same bench.

I've yet to build a diy flow bench but the one in is book was very simple and cheap if you want to give it a go

WE TODD DID

iTrader: (2)

Get some 6” long 1/2” egg shaped carbide burrs. They’re all over eBay for around $40. Alumacut will remove material fast, and a double cut will be a little less aggressive.

The sanding and smoothing of the ports is the least of your worries. Size and shape are what you’re going for.

Narrow the guide boss, and open the throats to 89% of the valve size. Then blend that back into the bowl. There is more that you can do, but you can really mess some **** up in a hurry.

Lsbmer

What he said, ^

You want keep the throat (seat %) cd high.. or its cfm per sq in. So 88-89% This head is known to fall dead quick at higher lifts. Can't turn So I would put some thought into the left wall if looking at intake manifold side and the width of area above the short turn And get the short turn right. And knock most of the rocker bump out. You could leave the finish the single cut alum burr finish. I doubt it flow much worse ,if at all worse, than a double cut burr. And you can make time with those burrs.
sanding rolls not needed. 37/45/64/75. .
the vj isn't the magic .its just one thing of many
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00pooterSS

iTrader: (40)

Practice on the 241's first

Then follow the rest of the advice

And absolutely don't skip the valve job (multiangle not just a valve lap)

HAte

Do a little reading of several diff articles about it.. Be confident take your time...and do it , if you have some mechanical ability and kbow how to use tools correctly youll be fine