SBC Head Porting ?

[70GMCer]

Are there any sources online that explains how to port sbc Heads?

thanks.........

[ureckme]

Heres some
http://www.chevyhiperformance.com/techarticles/95518/
http://www.sa-motorsports.com/diyport.shtm
Matt

[wolfthing2000]

Keep in mind that all the porting /polishing doesn't help a whole bunch for engines below, say ,5500 RPM. It is a lot of work and needs to be done carefully, so talk to your engine guy about it. Usualy an increase in valve size and a good cam will gain you what you are looking for. Headers help a bunch, especialy long tube for torque.

[ureckme]

He wasn't talk'n porting a 400 so dont hijack this post too. Matt

[wolfthing2000]

Back off you reek!! You are out there hunting me down for no reason and as a member of this board I have a right to post as I choose!!

If you don't have anything constructive to add, then move over or get out of the way, because I am a gonna be postin!!!!!!

[wolfthing2000]

Sorry about that GMCer. There are a few guys here who hate me evidently and are trying to black ball me
apparently.

I am just trying to help out and I keep getting bashed!!

All I can say is do your research.
Happy Chevrolet to ya!
Wolfthing

[chevy72blu]

good information there Ureckme.


Please keep comments like this in PM's.

[dropped_71chevy]

If you want to port your heads have at it but just keep it in mind when you put the rest of your combo together.

When I ported my heads it was fun, interesting, and a great learning experience

[70GMCer]

I've heard from others elsewhere, that just by knocking down the casting flash in the runners and doing mild pocket porting is all that's needed for HP and mileage gain. I'm not planning on doing an all out porting and polishing on a mild built 350 engine.

Just wanted directions on where not too take too much off in the pocket area. I am not going to do anything in the combustion area. Just looking for some free HP....

I'm also wondering if port matching the intake and heads are worth the extra effort. I will be install a Weiand Action+ and Edelbrock #1406 onto 1972 Z28, 194 heads. Also using a Crane 272H Energizer cam and lifters along with Headman Headers, & conected to a 350 Turbo with shift kit and stock stall. Also have 411's in the tailend. Planning on swapping over to a 700r later down the road.......

thanks, steve

[neonlarry]

If you are going to do some mild porting like you say, gasket matching is definitely worthwhile.

[wolfthing2000]

Talk to your engine machinist. This polishing porting and gasket matching only affects performance at higher RPM where you need all of that flow.
Do other things for the street.

If this is a race application, yes do it. If not be practical about it.

Unless you are drag racing from stop light to stop light that is!

[ureckme]

If you do 1/2 inch under the valve face on the intake on some head castings there will be a lot more flow. Matt

[70GMCer]

thanks to all that replied.......I'll be starting on this next week.........

[funky3821]

Cool get some pics on here of your process! I do porting for heads on the 3400 and I will only do port matching! Seeing that there is a difference you might need to do some work to make sure that the ports are the same from the intake to the heads! But I might be wrong! SO wait till someone agrees or disputes what I said!

[Liz]

Originally Posted by ureckme

He wasn't talk'n porting a 400 so dont hijack this post too. Matt

Originally Posted by wolfthing2000

Back off you reek!! You are out there hunting me down for no reason and as a member of this board I have a right to post as I choose!!

If you don't have anything constructive to add, then move over or get out of the way, because I am a gonna be postin!!!!!!

Both of ya'll need to reread the rules posted at the top of every forum and follow them... enough.. last warning.

[badone07]

Besides "mostly" what's stated above, this was a start to finish on 305 heads, but a good read anyway...Sitting Bull on Thirdgen

Use of Dremel tool will be a waste of time. Use an electric or pneumatic die grinder, speed regulated. That sa-motorsports kit in Matt's link, is a good read but the kit isn't really all that necessary if only going to do 1 set. Some double cut carbide cutters for the cast iron. For aluminum I use single cut cutters with penetrating oil. I use duct tape to protect the seats, doing bowl work. If doing clean up and/or polishing work in the combustion chamber, use an old set of properly sized valves to protect the seats. I would also suggest gloves, eye protection and good light source. Below is a borrowed pic of probably the most commonly used cutters. Wouldn't really bother with using any stones. Yes, I would also do the gasket match and do. Don't go crazy moving metal and if you have a junk set of heads laying around, practice removing metal on them. What casting numbers are you doing?

[70GMCer]

Thanks Badone07 and the rest of you for the info. The heads I've got are off a 72 Z28 and have already have a valve job done to them and shaved. It's the way I got them. I'll get the castings numbers later, as that's how I found out about what they came off of. The one thing I really don't want to do, is port match the intake. It's a new Weiand Action+ and I may change it later, and would make it hard to sell if any grinding had been done to it. I can still port match the intake gaskets to the runners thou, right? I'll do the picture thing as I progress on this venture......

[funky3821]

BTW,
http://www.widgetsupply.com/page/WS/...ing-flap-wheel
Look at the flapwheels! that is wha t I use to finish off the heads I do! Gives a real smooth finish! (aluminum 3400sfi heads) Again not sure if it is helpful but..............
Good luck

[badone07]

Originally Posted by 70GMCer

The one thing I really don't want to do, is port match the intake. It's a new Weiand Action+ and I may change it later, and would make it hard to sell if any grinding had been done to it. I can still port match the intake gaskets to the runners thou, right? I'll do the picture thing as I progress on this venture......

Yeah, you can and later if you decide to change intakes, you can match the new intake to the same gasket number. Flap wheels work nice to polish the exhaust, however a super high polish isn't really necessary although looking nice. The kit isn't really a bad investment. Really only used to polish, since the cutters finish is fine for the intakes and really not that bad for the exhaust. Shafts are 1/4" and not 1/8" like a dremel tool's. I like to radius and funnel the the oil return holes. Depending on cam choice, not a bad idea to yank the press in studs and tap for screw ins yourself. For mild street I also like to use the Mr. Gasket 1075 studs. Below is a pretty good "how to" from "Vader" on Thirdgen. I also like using poly locks or crane's kool nuts , even on stock rockers. Might seem like overkill to some, but having press in studs dislodge a few times, sucks. Just take your time.

http://216.121.161.76/files/RockerStudReplacement.pdf

[ureckme]

Badone07 that was a great link, it's kind'a like how I ported my 305 heads ( #081 ) for my 406. Porting that set of heads made a very big dif/ over not porting them. Now keep in mind I started porting 20 years ago and I screwed up the first set of heads I did but I didn't have good information like you can get from this site. Matt